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USMLE Physiology Step 1 MCQ
There are 5 different classes of immunoglobulins. What part of
the immunoglobulin determines it class:
a. light chains
b. Fab fraction
c. Fc fraction
d. the constant region of the heavy chain
e. the variable region of the heavy chain
f. reaction to antigen
g. how fast the antibody moves in blood
h. both light and heavy chains
According to differences in their heavy chain constant domains,
immunoglobulins are grouped into five classes or isotypes: IgG, IgA, IgM,
IgD, and IgE. D
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Labels: class, IgA, IgE, IgG, IgM, Immunoglobulins
T U E S D A Y , F E B R U A R Y 1 7 , 2 0 0 9
USMLE MCQ Step 1 & 2- MCQ
A 7 month old infant with multiple medical problems required
intravenous access. The medical student asked the radiology
resident to help place the long peripheral line in the left arm.
Once the line was placed, a chest x ray was obtained. please see
the attached link. The next step in the management of the infant
is?
a. fire the medical student
b. fire the resident
c. remove the line
d. hide the x ray
e. hide the infant
f. leave the line alone
g. put a new line in the right arm
h. pull the line until it is just at the tip of the heart
ANS: The chest x ray shows a PICC line placed in the arm and entering the
left axillary and subclavian vein. Then the line enters the heart
through the LEFT SUPERIOR VENA CAVA, goes through the coronary
sinus and comes out of the inferior vena cava. This is not abnormal. All of
us have one superior vena cava on the RIGHT. Some infants born with
congenital heart disorders also have a left superior vena cava. The left
superior vena cava then connects to the coronary sinus in the right
atrium. THE LEFT SUPERIOR VENA CAVA IS NORMAL. Sometimes it may
open into the left atrium and this is known as an unroofed coronary sinus
and acts like an atrial septal defect. In general, the shunting is minimal
and nothing needs to be done.
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W E D N E S D A Y , F E B R U A R Y 1 1 , 2 0 0 9
USMLE step 1 & 2, Microbiology MCQ
A 5 yo presented to the ER with stridor and drooling in a child.
The mother says the child has not been able to eat and is crying.
He is febrile and irritable. He has no past medical history of any
significance, nor does he have any allergies. He is barely able to
open his mouth. A lateral head and neck x ray is obtained. Follow
this link for the x ray- ( a-5-yo-) What should not be done to this
patient?
a. give oxygen
b. start antibiotics
c. have tracheostomy set at bed side
d. oral examination and obtain swabs for culture
e. observe closely in ICU
Epiglottitis is a medical emergency that may result in death if not treated
quickly. The epiglottis is a small flap of tissue that is located at the tongue
base. It's function is to prevent food from going down the trachea during
swallowing
When the epiglottitis is infected or inflamed it can quickly obstruct the
large ariways and prevent air from going down the trachea. The posterior
throat is tender and one is not able to swallow- thus most individuals
drool.
The infection often spreads to the surrounding areas. With continued
inflammation and swelling of epiglottis, complete blockage of the airway
may occur. Death is not unheard of. when a patient presents with such a
scenario, the last thing one should do is inspect the mouth. the slightest
irritation can lead to complete shutdown of the airways. all precautions for
an emergency airway must be made available at the patient's bedside.
Epiglottitis is an infection of children and almost never seen in adults.
Today, vaccination against Haemophilus influenzae type b (has
significantly decreased the incidence of epiglottitis in children.
Epiglottitis caused by Hib is most common in children aged 2-7 years but
for some unknown reason has not been reported among Navajo Indians
and Alaskan Eskimos.
X ray show a V Shaped air density and then no more air going into the
trachea. The rapid tapering of air entry (V sign) is often seen in children
who have epiglottitis. This tells you that the trachea is blocked from the
excess swelling and any manipulation of the mouth can immediately
cause respiratory arrest. Always have an emergency tracheostomy kit at
the bedside incase you need access to the airways.
Make no attempt at home to inspect the throat of a person suspected of
having epiglottitis.
Manipulation of the oral cavity may result in sudden airway closure. Even
oral intubation is considered dangerous and thus a tracehostomy set
should always be placed at the bedsite.
Primary treatment of epiglottitis is relieving stress, giving oxygen, have a
quiet environment and close monitoring. IV fluids and antibiotics should
be administered.
For more pictorial based questions for the USMLE, step 1 and 2, write
to Nirihs01@hotmail.com
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Labels: USMLE Microbiology MCQ
USMLE ECG Review MCQ
A 43 yo female with a dilated cardiomyopathy suddenly
developed this rhythm (see link). The patient has a BP of 50/10
and the pulse is non existent. You are on call to the Medical Floor
and the nurse asks you to do something quick. Please look at the
attached link and decide what the best treatment is?
a. beta blocker
b. quinidine
c. amiodarone
d. digoxin
e. Defibrillation
Amiodarone is an anti arrhythmic drug used for various types of
tachyarrhythmias, both ventricular and supraventricular (atrial)
arrhythmias. it is a superb drug which can immediately reverse atrial
fibrillation and is also helpful for ventricular tachycardias. However, in any
patient with low blood pressure and a rhythm which is shown (VF), urgent
defibrillation is required. The first treatment of choice in a patient with
ventricular fibrillation is defibrillation at 360 joules. E
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Labels: USMLE ECG
T U E S D A Y , F E B R U A R Y 1 0 , 2 0 0 9
USMLE Step 1 Review -Pharmacology
please select the one correct answer
1. A 19 yo with no symptoms had this ECG before a work out. He
did have abnormal palpitations a year ago but required no
therapy. He was not given any medical therapy but did try some
over the counter herbal medications. His ECG is shown here. hb-
11 . He most likely has?
a.first degree HB
b.atrial flutter
c.Normal sinus rhythm
d.atrial fibrillation
e.ventricular arrhythmia
f.Torsades de pointes
First degree heart block is fairly common. It can sometimes be found in
teenagers, young adults and in well-trained athletes. The condition may
be caused by rheumatic fever, some types of heart disease and by some
drugs. First-degree heart block causes no symptoms. When the PR
interval is > 0.2 ms, the diagnosis of first degree HB is made. This type of
HB is fairly common in young teenagers and in athletes. It can be caused
by congenital heart disease and some drugs like digoxin. The disorder is
asymptomatic and requires no treatment. C
2. A 43 yo with mitral stenosis is found to have a dilated left
atrium. She is asymptomatic and had a BP of 90/50. You are
unable to feel her pulse. The chest x ray reveals a large heart. As
a precaution, your chief resident decides to place her on warfarin.
Of all the below ECG rhythms, she most likely has?
a. atrial flutter
b. premature atrial beats
c. first degree heart block
d. atrial fibrillation
e. ventricular tachycardia
f. sinus tachycardia
Atrial fibrillation is common with advancing age; however other causes
include uncontrolled hypertension, coronary disease, CHF, valvular heart
disease, acute pulmonary processes, hyperthyroidism, and acute alcohol
intoxication. Patients having undergone cardiac, pulmonary, or
esophageal surgery have a 20-40% postoperative incidence of atrial
fibrillation (AF). Patients with congenital heart disease are at higher risk
for developing AF. The most common arrhythmia seen in patients with
mitral stenosis is atrial fibrillation. The dilated atrium also has a tendency
to form a clot which frequently embolizes. D
3. The most common type of immune deficiency in children is?
a. AIDs
b. DiGeorge
c. Selective IgA
d. SCID
e. CGD
The most common congenital immune deficiency is selective IgA. There
also exists selective IgM and IgG deficiencies, but they are less common.
IgA deficiency may be due to a failure of heavy-chain gene switching. C
4. Deficiency of the enzyme adenosine deaminase (in RBCs) is
seen in?
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. Jobs
Autosomal Recessive. Adenosine Deaminase deficiency leads to
accumulation of dATP. This leads to a decrease in DNA precursors
molecules. Severe deficiency in both humoral and cellular immunity
occurs due to impaired DNA synthesis. Bone marrow transplant may be
helpful in treatment. B
5. Fibrinolytic therapy can be used in all medical disorders
except:
a. a recent hemorrhagic brain injury
b. recent head trauma
c. closed head or facial injury
d. presence of a brain tumor
e. presence of a brain AV malformation or a hemangioma
f. presence of an aortic dissection
g. embolic occlusion of the femoral artery
h. DIC
i. Active GI bleed
Fibrinolytic therapy should never be used if there in any condition where
bleeding has occurred or can occur. The majority of embolic occlusions of
arteries are from blood clots. In such cases, fibrinolytic therapy can be
used to dissolve the blood clot. G
6. After starting a patient on a heparin drip for a pulmonary
embolus, the earliest time to monitor the first set of PTT is:
a. 4-6 hrs
b. 12 hrs
c. 24 hrs
d. 1 hr
e. 4 hrs
After starting Heparin, the PTT is monitored every 4-6 hrs for the first 24
hours. When the PTT is therapeutic between 55-70 s, the PTT can be
monitored on a daily basis. A
7. The lytic agent which acts directly on plasminogen is:
a.Streptokinase
b.Urokinase
c.Hirudin
d.Warfarin
e.Heparin
f.Plavix
g.Ticlodipine
h.Aspirin
Urokinase is a serine protease which acts directly on plasminogen.
Urokinase is also found in physiological amounts in the blood and
prostate. It has the ability to directly act on plasminogen and breaking it
into plasmin. The activated plasmin then breakdowns the blood clot or
thrombin. A
8. A 49 year old female is admitted with pain her left calf. You
suspect she may have a DVT and order a Doppler ultrasound. The
test indicates that she has a 3 cm blood clot in the proximal
popliteal vein. You decide to start her on an anti coagulant.
Which is false about Heparin?
a. It is a mucopolysaccharide
b. It is often administered two – three times daily
c. It binds to anti-thrombin 111 for its mode of action
d. It can be used as an oral dose when treating DVT
e. A PTT times should be monitored in patients receiving Heparin
f. It occurs naturally in the body
Heparin is a mucopolysaccharide, which is normally found in the basophils
and mast cells. It acts as an anti coagulant and helps prevent the
formation of blood clots. Unlike fibrinolytics, heparin does not break down
the already formed clots. Heparin is used to treat a variety of medical
disorders including acute myocardial infarction, atrial fibrillation, deep
vein thrombosis, pulmonary embolism; Heparin can never be used as an
oral agent and is ether administered subcutaneously or intravenously. Its
activity needs to be monitored by measuring PTT levels. D
9. The following patient is started on heparin. During the 3rd day,
you are asked which of the following is not a complication of
Heparin therapy.
a.Thrombocytopenia
b.osteoporosis
c.alopecia
d.urticaria
e.skin necrosis
Heparin is generally a safe drug but does have a few side effects. The
most serious is heparin induced thrombocytopenia (HIT) which presents
with occlusion of the arteries. The heparin should be stopped immediately
and the platelet count should be monitored. The condition can be
reversed and heparin use should be avoided. Other rare side effects of
heparin include osteoporosis, alopecia, uritcaria, skin necrosis commonly
occurs with Warfarin. E
10. Which of the anti coagulants has been associated with skin
necrosis?
a. aspirin
b. Ticlodipine
c. Warfarin
d. Urokinase
e. streptokinase
Rarely, Warfarin has been known to cause a severe type of skin necrosis.
This adverse side effect generally tends to occur early after initiation of
treatment and has been linked to protein C or S deficiency. Protein C is an
innate anticoagulant that, like the procoagulant factors that Warfarin
inhibits, requires vitamin K-dependent carboxylation for its activity. Since
Warfarin initially decreases protein C levels faster than the coagulation
factors, it can paradoxically increase the blood's tendency to coagulate
when treatment is first begun. This is the reason why many patients are
fist given heparin prior to starting Warfarin. Occasionally, large blood clots
may form all over the body, esp. the extremities. C
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Labels: USMLE Review Step 1
USMLE Step 1 Respiratory Pharmacology
Please choose one correct answer
1. The anti-asthmatic drug that can cause convulsions and
arrhythmias is?
a.Prednisone
b.Salmeterol
c.Zafirlukast
d.Theophylline
e.Ipratropium
Symptoms of toxicity of Theophylline include Abdominal pain, continuing
or severe; confusion or change in behavior; convulsions (seizures) ; dark
or bloody vomit; diarrhea; dizziness or lightheadedness; fast and/or
irregular heartbeat; nervousness or restlessness, continuing; trembling,
continuing. D
2. The mode of action of the Methylxanthines is?
a.inhibit Choline esterase
b.inhibit Phosphodiesterase
c.stimulate c-GMP
d.stimulate Beta-1 receptors
e.inhibit MAO
Methylxanthines inhibit Phosphodiesterase and increased CAMP. These
agents increase the contraction of the diaphragm. The most common
adverse side effects of these agents is nausea, but cardiac arrhythmias,
convulsion may also result. Beta blockers are useful agents to prevent the
side effects of theophylline. B
3. The methylxathnine that has been used to treat intermittent
claudication is?
a. Pentoxifylline
b. aspirin
c. theopylline
d. warfarin
e. ticlodipine
Pentoxifylline is said to improve symptoms of intermittent claudication by
decreasing blood viscosity A
4. The longest acting B2 bronchodilator is?
a. Ipratropium
b. Albuterol
c. Salmeterol
d. Theophylline
Salmeterol is long acting beta 2 agonists. C
5. The prophylactic agent of choice for treatment of asthma is?
a. Cromolyn acetate
b. Prednisone
c. Ipratropium
d. Salbutamol
e. Theophylline
Cromolyn and nedocromil are given as aerosols for asthma. These
prophylactic agents inhibit the release of mediators form the mast cells.
They have no bronchodilator action but are capable of preventing early
and late responses to antigens. A
6. Bronchodilators which are first line agents in COPD are?
a. Ipratropium
b. Prednisone
c. Salmeterol
d. Ephedrine
e. Zafirkulast
Ipratropium is an antimuscarinic agent and prevents bronchoconstriction.
It is used also in asthmatic and is an effective first line drug. A
7. Anti-asthmatic drug that inhibit the leukotrienes receptor is?
a.Zafirlukast
b.Salbutamol
c.Ipratropium
d.Prednisone
e.Epinephrine
Zafirkulast is an oral leukotriene receptor antagonist used for treating
asthma. Leukotrienes are a group of chemicals manufactured in the body
from arachidonic acid. Release of leukotrienes within the body, for
example, by allergic reactions, promotes inflammation in many diseases
such as asthma, a disease in which inflammation occurs in the lungs.
Zafirlukast blocks the binding of leukotriene types D4 (LTD4), and E4
(LTE4). The drugs are orally active and have been shown to be effective in
preventing exercise and antigen asthmatic attacks. A
8. An asthmatic has been prescribed oral steroids for 2 weeks. He
later presents with a sore throat and pain on eating food. He
claims that his food does not taste right. The best treatment for
him is?
a.oral Nystatin
b.increase dose of steroids
c.decrease dose
d.start Acyclovir
e.start proton pump inhibitor
Oropharyngeal candidiasis is common with use of steroids. When steroids
are prescribed for any length of time, oral Nystatin should be prescribed.
A
9. Aspirin allergy is related to?
a.Arachidonic acid
b.Bradykinin
c.Leukotrienes
d.Histamine
e.Serotonin
Aspirin allergy results from the formation of leukotrienes. The leukotrienes
are known to cause bronchoconstriction. C
10. The slow releasing substance of anaphylaxis is?a. Histamine
b. Bradykinin
c. Serotonin
d. Leukotrienes
e. Acetylcholine
The leukotrienes comprise the important mediators of
bronchoconstriction. D
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Labels: USMLE Respiratory Pharmacology MCQs
USMLE Pharmacology- Heart Failure
Please select the one correct answer
1. For a 65 year old male with shortness of breath, diaphoresis
and basilar rales on auscultation, the least likely drug of choice
is:
a.Captopril
b.Furosemide
c.Atenolol
d.Digoxin
e.Minoxidil
Minoxidil is an alpha antagonist and has no role in the treatment of CHF. It
is used in the treatment of hypertension and has an odd side effect of
excess hair growth. E
2. A 59 year old female is placed on digoxin for atrial fibrillation.
He is seen in the medical clinic and you decide to add another
drug to his therapy. Which of the following drugs can increase the
toxicity of digoxin?
a.Potassium supplements
b.Vasotec
c.Vitamin D
d.Quinidine
e.Atenolol
Quinidine is known to enhance the toxicity of digoxin by displacing digoxin
from the protein binding sites . D
3. A 71 year old female is admitted to the ICU with shortness of
breath and diaphoresis. She has been unable to lie down flat in
the bed. Auscultation reveals basilar rales and the presence of an
S3. She is unable to eat and you decide to start her on
intravenous therapy. The medication which can only be
administered intravenously is:
a.Digoxin
b.Captopril
c.Quinidine
d.Dobutamine
e.Amiodarone
Dobutamine is an inotropic agent with Beta 1 receptor agonist activity.
Besides increasing the force of contraction of the heart, it can also be a
vasodilator to the pulmonary arteries. D
4. A 71 year old has uncontrolled atrial fibrillation. He is
cardioverted and then started on oral digoxin therapy. He is later
seen in the ER with complaints of diarrhea, yellow vision and first
degree heart block. His condition has most likely been worsened
by?
a. hyperkalemia
b. hyponatremia
c. hypocalcemia
d. hypercalcemia
e. hypermagnesemia
Digoxin toxicity is worsened by hypokalemia, hypomagnesemia and
hypercalcemia. The toxicity is also worsened by Quinidine toxicity C
5. You have decided to admit a patient with a heart attack to the
ICU. Four hours later, he is very dyspenic and the chest x ray
reveals an enlarged cardiac silhouette with Kerley B lines. Echo
reveals an ejection fraction of 20% and you start him on an agent
which inhibits the enzyme phosphodiesterase. The drug is?
a.Digoxin
b.Quinidine
c.Amrinone
d.Dobutamine
e.Amiodarone
Amrinone and milrinone are inotropic agents which act by inhibiting
phosphodiesterase. These agents increase the levels of cyclic AMP. C
6. A 71 year old with congestive heart failure is admitted to the
ICU. He is treated with diuretics, oxygen and a nitroglycerine
drip. Over the nest few days he improves and is transferred to
the floor. You decide to place him on a drug class that has been
shown to reduce mortality in patients with CHF. Your drug of
choice is
a.Beta blockers
b.Calcium channel blockers
c.Diuretics
d.ACE inhibitors
e.Phosphodiesterase inhibitors
ACE Inhibitors have been shown to reduce mortality and morbidity in CHF.
These agents reduce aldosterone secretion, salt and water retention and
decrease afterload. These agents are now considered first line drugs for
CHF D
7. Which of the following is false about digitalis?
a. increased PR interval is an early effect of digoxin
b. increase automaticity is caused by intracellular calcium overload
c. decrease in conduction occurs at the AV node
d. the electrical effects of digoxin are mediated by the sympathetic
system
e. premature ventricular beats can occur with digoxin
The major electrical effects of digoxin are mediated by a parasympathetic
response which causes the slowing of the heart. These effects can be
reversed by Atropine. The basic effect of digoxin is to slow the ventricular
rate. D
8. Digoxin is used for all the below conditions EXCEPT:
a.atrial flutter
b.atrial fibrillation
c.CHF
d.ventricular tachycardia
Digoxin is the classic drug for CHF. However, it is now being replaced with
better and safer drugs. The drug has a tendency to cause toxicity which
can be aggravated by the use of diuretics and Qunidine. Digoxin has also
been used in the treatment of atrial fibrillation and flutter D
9. Which of the following statements is false about class 1
antiarrhythmic agents?
a.Quinidine can be used to treat both atrial and ventricular arrhythmias
b.Procainamide can cause a lupus like syndrome
c.Cinchonism can occur with the prolonged use of Quinidine
d.orally administered Lidocaine is effective for ventricular arrhythmias
e.Quinidine worsens digoxin toxicity
Lidocaine is useful for treatment of ventricular arrhythmias; especially
those occurring after an MI. Lidocaine can be administered intravenously,
intramuscular and even placed down the oral endotracheal tube. It is
never given orally as it is rapidly hydrolyzed. D
10. The toxicity of class 1 antiarrhythmic agents can be treated
with?
a.Lidocaine
b.Digoxin
c.Sodium lactate
d.diuretics
e.steroids
All class 1 antiarrhythmic agents have the potential to cause arrhythmias.
Torsades can occur with quinidine. Hyperkalemia can worsen the toxicity
of these agents. Treatment of overdose is with sodium lactate to reverse
the hypotension and arrhythmias. C
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Labels: USMLE Heart Failure MCQs
USMLE Step 1 Pharmacology- Anti Arrhythmics
Please Select one correct answer.
1. A 55 year old previously healthy male has been complaining of
chest palpitations for the past 3 months. He is seen in the
cardiology clinic. After a quick physical exam, the ECG reveals
that he has atrial fibrillation. Five minutes later, you noticed that
the patient is not responsive and has a Blood Pressure of 60/20.
The next step in his management is?
a. Amiodarone
b. Quinidine
c. Lidocaine
d. Cardioversion
e. Digoxin
In any hypotensive patient with an arrhythmia, Cardioversion should be
the first step. D
2. Which of the following is false about Amiodarone?
a. is used for both atrial and ventricular arrhythmias
b. blocks sodium, calcium and potassium channels
c. can cause corneal deposits
d. pulmonary fibrosis is common
e. has a very short half life
Amiodarone is very effective for all arrhythmias but is limited in its used
by its toxicity. It acts by blocking the sodium calcium and potassium
channels. It has a number of toxicities including pulmonary fibrosis,
corneal deposits, hypothyroidism and tremor. The drug has a very long
half life. E
3. Which of the following is false about beta blockers?
a. Metoprolol is useful in the treatment of patients after an MI
b. Metoprolol can depress the cardiac output
c. Beta blockers reduce arrhythmias
d. Timolol can be used to treat glaucoma
e. oral Esmolol is effective for outpatient treatment of hypertension
Esmolol is a very short acting beta blocker for intravenous administration
of atrial arrhythmias and hypertension. The majority of beta blockers are
commonly used as prophylactic agents in patients who have had an MI.
these agents can also decrease atrial arrhythmias. Use should be
cautioned in patients with poor ejection fraction as these agents are
negatively inotropic. E
4. Which of the following is false about Adenosine?
a. Adenosine is a normal component of body tissues
b. the drug is effective is treating atrial arrhythmias
c. it has a very short duration of action
d. hypotension can occur
e. it depolarizes the AV node to decrease the nodal arrhythmias
Adenosine is normal component of the body and when given
intravenously it is very effective for abolishing nodal arrhythmias. It acts
by hyperpolarizing the tissues. It has a very short duration of action and
can cause flushing and hypotension. E
5. Which of the following is false about calcium channel blockers?
a. can be used to treat hypertension and arrhythmias
b. block L calcium type channels
c. PR interval is typically shortened by these agents
d. Effective in patients with congestive heart failure
e. can be used to treat coronary artery spasm
Calcium channel blockers are widely used in the treatment of atrial
arrhythmias, hypertension and in the treatment of Prinzmetal’s angina.
These agents act by blocking the type calcium channels. They are
negative inotropes and should be used with caution in patients with heart
failure. D
6. Digoxin induced arrhythmias can be decreased by?
a.Calcium
b.Sodium
c.Magnesium
d.Uranium
e.Chromium
Magnesium is now felt to be an important ion in the genesis of
arrhythmias induced by digoxin. Magnesium is also used to treat
Torsades. Occasionally potassium depletion may not be reversed until the
magnesium deficiency has first been corrected. C
7. The beta blocker which is classified as a class 3 anti-arrhythmic
agent is?
a.Metoprolol
b.Atenolol
c.Esmolol
d.Sotalol
e.Pindolol
Sotalol is in the same anti arrhythmic class drug as Amiodarone. It is used
in the treatment of ventricular arrhythmias. D
8. The major mechanism of class 3 anti arrhythmic agents is?
a.inhibition of Sodium influx
b.inhibition of l type Calcium channels
c.reducing outward phase of Potassium current
d.inhibiting Na K ATPase
e.inhibiting Phosphodiesterase
The hallmark of class 3 drugs is prolongation of the action potential
duration. The action potential prolongation is caused by blockade of the
potassium channels that are responsible for repolarization of the action
potential C
9. The agent which can sometimes be used to treat digoxin
induced arrhythmias is?
a.Quinidine
b.Amiodarone
c.Phenytoin
d.Sotalol
e.Fleicanide
Phenytoin is an anticonvulsant and is sometime used to treat digoxin
induced arrhythmias. C
10. The diuretic used in the treatment of mountain sickness is?
a. Acetozolamide
b. Furosemide
c. Thiazide
d. Spironolactone
e. Mannitol
Acetozolamide is used principally in veterinary medicine for its effects on
aqueous humor production in the treatment of glaucoma. It has also been
used for its diuretic action and in the treatment of metabolic alkalosis. In
humans, the drug has been used as adjunctive therapy for epilepsy and
for acute high-altitude sickness. A
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Labels: USMLE Anti Arrhythmics MCQs
USMLE Step 1- Surgical Anatomy MCQs
Please Select the one correct answer
1. You are in the anatomy laboratory and dissecting the heart and
lung. Suddenly you wonder what the first branch of the aorta is?
a. right brachiocephalic artery
b. left common carotid
c. left subclavian artery
d. right coronary artery
e. right common carotid artery
The right coronary is the first branch of the aorta. D
2. A patient has been involved in a MVA. He presents to the
emergency room with severe pain in his right chest. The chest x
ray reveals numerous rib fractures and pulmonary contusion.
Which finding on the physical examination would make you
suspect that would make you suspect flail chest is?
a. difficulty breathing
b. increased stridor
c. paradoxical breathing
d. low oxygen saturation
e. pain
f. hyperventilation
Paradoxical breathing is a sin que non of flail chest. These patients need
arterial blood gas monitoring, pain control and pulmonary care. C
3. The main reason a tracheostomy is not performed on the first
cartilage ring is because:
a. trachea is too narrowb
b. a high chance of subglottic stenosis
c. a high chance of tracheo-innominate artery fistula
d. inability to access it
e. technically impossible
f. chance of damaging esophagus
Tracheostomy performed in the first cartilage ring can result in subglottic
stenosis, which is almost impossible to repair. B
4. The most common mass in the anterior mediastinum in an
adult is?
a. thymoma
b. thyroid
c. teratoma
d. lymphoma
e. leukemia
f. seminoma
Thymoma is the most common mass of the anterior mediastinum. A
5. The left lateral border and apex of the cardiac silhouette is
made up by the
a. right atrium
b. right ventricle
c. left atrium
d. left ventricle
The left ventricle makes up the major border of the left cardiac silhouette.
D
6. An angiogram reveals stenosis of the right innominate artery.
The surgeon asks you to get the patient ready for surgery. You
tell him that your anatomy knowledge is excellent. The artery can
best be exposed by a?
a. right thoracotomy
b. right supraclavicular incision
c. median sternotomy
d. neck incision
Innominate artery is best exposed by a median sternotomy. C
7. A patient with a traumatic aortic rupture undergoes aortic
repair. The patient presents with hoarseness after surgery. The
most likely cause of hoarseness is?
a. postoperative viral infection
b. damage to phrenic nerve
c. trauma to recurrent laryngeal nerve
d. injury to sympathetic chain
e. damage to vocal cords during intubation
Hoarseness is due to injury to the recurrent laryngeal nerve. The recurrent
nerve runs in between the left common carotid and the left subclavian
and can easily be injured by placing a clamp in that region. C
8. A 35 year old male is involved in a head on motor vehicle
accident. On arrival to the emergency room, he has severe
bruises to his chest but is otherwise stable. The chest X ray
reveals a widen mediastinum. An angiogram is ordered which
reveals a traumatic aortic rupture. The most common site of
aortic rupture after severe blunt trauma to the chest is ?
a. ascending aorta
b. abdominal aorta
c. aortic arch
d. descending aorta distal to left subclavian artery
e. femoral artery
f. left common carotid artery
Following blunt trauma, the descending aorta just distal to the left
subclavian artery is most prone to injury. A chest x ray will reveal a widen
mediastinum and a CT scan is required for diagnosis. D
9. A new born is seen in the infectious disease clinic due to
repeated Candida infections. Blood work reveals that he has very
low levels of calcium and has suffered from numerous tetany
spells. He most likely has:
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. Jobs
f. renal failure
T-Cell deficiency from no thymus. Hypocalcemic tetany from primary
parathyroid deficiency. C
10. Failure to develop the 3 and 4th pharyngeal pouches are
linked to what immune disorder?
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. Job’s
Failure of development of the 3rd and 4th Pharyngeal Pouches leads to
agenesis of the thymus and parathyroid glands. C
For a complete set of USMLE Review Questions, write to
Nirihs01@hotmail.com
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Labels: USMLE Anatomy MCQs
M O N D A Y , F E B R U A R Y 9 , 2 0 0 9
USMLE Trauma MCQs
1. A 71 year old is admitted to the CCU and needs invasive
monitoring. It is decided to place a swan Ganz catheter and
measure the pulmonary catheter wedge pressure. This will allow
one to assess the pressure in the?
a. Right atrium
b. Left atrium
c. Left ventricle
d. Right ventricle
e. Aorta
f. Inferior vena cava
Pulmonary capillary wedge pressure (PCWP) provides an indirect estimate
of left atrial pressure (LAP). Although left ventricular pressure can be
directly measured by placing a catheter into the left ventricle by feeding it
through a peripheral artery, into the aorta, and then into the ventricle, it is
not possible to place the catheter into the left atrium unless there was an
atrial septal defect present. The swan Ganz catheter is usually inserted at
the bedside under sterile conditions. It is frequently used to monitor
patients in the CCU and ICU. B
2. A 64 year old male in the ICU needs quick IV access. The
resident decides to insert a central venous line. Which is not a
complication of right internal jugular puncture?
a. pneumothorax
b. hemomediastinum
c. thoracic duct injury
d. tracheal puncture
e. phrenic nerve injury
f. carotid artery dissection
g. injury to esophagus
Central line insertion can be associated with a number of complications.
However, the benefits derived from their benefits far over-ride the risks of
potential complications. The most common complication of central line
insertion is pneumothorax. There is a belief that the incidence of
pneumothorax is higher if the central line is attempted via the subclavian
vein. Many physicians utilize ultrasound to help identify the neck veins
before cannulation. The reported incidence of pneumothorax is about 1%
but this is under reported.
Other complications of central lines include infection chiefly from
Staphylococcus aureus and Staphylococcus epidermidis. The risk of
infection are high when the individual is diabetic, immunocompromised
and obese. When a central line infection is suspected, the line should be
removed and the tip sent for culture. If the individual is febrile, blood
cultures should be obtained. No new line should be re inserted until the
cultures are negative or the fever has subsided.
Other rare complications of central lines include injury to the carotid
artery, air embolism, arrhythmias, pericardial tamponade and pain. G
3. A 45 year old obese female undergoes a laparotomy. The best
way to manage her post operative pain is?
a. over the counter pain pill
b. pain medication PRN
c. patient controlled analgesia
d. Epidural anesthesia
e. acupuncture
Patient controlled analgesia is best for most individuals esp. children and
obese individuals. C
4. A 57 year old has been told that he has a mass behind the left
knee. Ultrasound reveals that it is a vascular mass. In general,
the most common presentation of a popliteal artery aneurysm
begins with?
a. pain
b. mass behind knee
c. decreased pulses
d. claudication
e. sudden onset of left cold leg
Popliteal artery aneurysms are the most common peripheral arterial
aneurysms and the second most common aneurysm after abdominal
aortic aneurysms. In the past, popliteal aneurysms have been associated
with a high rate of limb loss. When the aneurysm ruptures, there is a
sudden loss of blood supply to the distal leg. In many cases, embolization
to the distal blood vessels of the foot is also common.
Because of this awareness, all individuals with either asymptomatic or
symptomatic aneurysms of ≥ 2 cm in diameter should be considered for
elective pass surgery. While surgery was the standard of care in the past,
this has no changed with the availability of endovascular therapy.
Endovascular stenting is also an excellent option in the presence of a
ruptured aneurysm. Once a stent has been placed it is important that the
patient be placed in anticoagulation medications like ticlodipine. E
5. A 35 yo female has just delivered a baby and 2 days later is
found to have a swollen left leg. Ultrasound shows a deep vein
thrombus just beneath the popliteal vein. The next step in her
management is?
a. coumadin
b. heparin loading then infusion
c. low molecular weight heparin
d. Aspirin
e. Green field filter
The primary aim for the treatment of DVT is to prevent pulmonary
embolism, reduce morbidity, and prevent or minimize the risk of
developing the postphlebitic syndrome. Anticoagulation is the mainstay of
the initial treatment for DVT. One may use either unfractionated heparin
or low molecular weight heparins to treat the DVT. Heparin does not lyse
the thrombus but prevents extension of thrombus. Heparin has been
shown to significantly reduce (but not eliminate) the incidence of fatal and
nonfatal pulmonary emboli as well as recurrent thrombosis. The chief
reason for the continuing risk of PE is mainly because heparin does not
affect the preexisting nonadherent thrombus. Heparin does not affect the
size of existing thrombus nor does it have any intrinsic thrombolytic
activity.
In less than 10% of patients is heparin therapy associated with complete
lysis. Heparin therapy has little effect on the risk of developing the
postphlebitic syndrome. The deep vein thrombus usually causes
destruction of the valves which almost always results in a high incidence
of chronic venous insufficiency and postphlebitic syndrome.
Warfarin therapy is usually started 3-5 days after heparin. The INR is
maintained anywhere between 2-2.5. Heparin must be overlapped with
oral warfarin because of the initial transient hypercoagulable state
induced by warfarin. This effect is related to the differential half-lives of
protein C, protein S, and the vitamin K–dependent clotting factors II, VII,
IX, and X. Long-term anticoagulation is definitely indicated for patients
with recurrent venous thrombosis and/or persistent or irreversible risk
factors. B
6. A 20 year old was involved in a motor vehicle accident. He had
severe blunt chest trauma to the chest. In the ER he received 8
units of packed red blood cells. Soon after he became short of
breath and his PO2 was 55 on 100% oxygen. His chest x ray
revealed a complete white out and he had a Central venous
pressure of 11. At 48 hours after the injury, the nature of his lung
injury was most likely due to?
a. pulmonary contusion
b. ARDs
c. Pneumonia
d. PE
e. heart failure
f. lung fibrosis
Bruising or contusion of the lug is common after chest trauma. The
condition results in lung injury which is often marked by fluid and blood
accumulation in the lung parenchyma. This results in difficulty in
oxygenation and hyperventilation. In lung contusion the lung tissue
structure is intact and there is no frank tear or rupture. Pulmonary lung
contusion rarely occurs in isolation and is often associated with rib
fractures or soft tissue injury. The typical signs of lung contusion include
chest pain, fever, tachypnea and hemoptysis. The chest x ray may reveal
signs of a lung contusion, but a CT scan is definitive. A
7. A 43 yo is involved in a car accident and breaks both femurs.
There is concern that he may develop fat embolism syndrome.
The radiographic findings of fat embolus are most typically
evidenced at?
a. 0-12 hrs
b. 12-24 hrs
c. 24-48 hrs
d. 48-72 hrs
There is no radiological feature which is diagnostic of fat embolism
syndrome. Infact in the first few hours after injury, the chest x ray may be
completely normal. Over the next 48 hours, some patients may develop
bilateral fluffy shadows which are associated with a decline in the
respiratory status. Some individuals may develop diffuse or patchy air
space consolidation, due to edema or alveolar hemorrhage; this is most
prominent in the periphery and bases. Radiological studies like the
Ventilation/perfusion scans may demonstrate a mottled pattern of sub-
segmental perfusion defects with a normal ventilator pattern. In most
cases, the earliest features on x ray may be seen around 48-72 hours.
CT may identify ill defined areas of centrilobular and sub pleural nodules
representing alveolar edema, microhemorrhage, and inflammatory
response secondary to ischemia and cytotoxic emboli may be seen. MRI of
the brain may reveal high-intensity T2 signals; this correlates with the
degree of neurological impairment found clinically.
Fat particles are not present in more than 50% of individuals with fat
embolism syndrome. There are some who advocate the use of
bronchoscopy with bronchoalveolar lavage to detect fat droplets in
alveolar macrophages as a means to diagnose fat embolism has been
described in trauma patients and patients with the acute chest syndrome
of sickle cell disease. However, diagnostic criteria vary and the sensitivity
and specificity are unknown. D
Posted by sbmedex at 8:38 PM 0 comments Links to this post
Labels: USMLE Trauma MCQs
USMLE Step 1 Review No 2
Please select one correct answer
1.A 67 year old male presents with pain and a throbbing right
sided headache. Examination reveals a tender temporal artery
and a biopsy is immediately done. The classic findings on
pathology will reveal?
a. granulomas in internal elastic lamina
b. granulomas in the adventitia
c. granulomas in endothelium
d. hemorrhagic infarct
e. liquefactive necrosis
f. caseating granulomas
g. inclusion bodies
Histopathology in temporal arteritis will reveal an inflammatory infiltrate
surrounding a fragmented internal elastic lamina within the media of an
vessel wall. Predominantly mononuclear cells with giant cell formation are
seen, indicating the presence of a chronic inflammatory process.
Temporal arteritis is often known as giant cell arteritis and is a disorder of
the medium sized arteries, esp in the head and neck area. the temporal
artery is a branch of the external carotid artery and is often involved in
the disease process.
The disorder may occur in association with polymyalgia rheumatica in
about 25% of cases, which is characterized by the sudden onset of muscle
pain, fever and fatigue. the disorder usually occurs in the elderly. When
the temporal artery biopsy is positive for inflammation, the patient needs
to be urgently treated with corticosteroids to prevent blindness. A
2. A 4 year old child is seen in the hematology clinic with a large
discolored lesion on his trunk and left thigh. The mother says that
he has had the lesion since birth but it has grown over the past 3
months. She denies any other problems. The blood work reveals a
PT of 12.3, PTT of 38, CBC of 5, WBC of 11.2 and platelets of 25.
Examination reveals a large hemangioma which is non tender and
there is no evidence of bleeding. The most likely diagnosis is?
a. hemophilia
b. von willebrands disease
c. Kassebach merit syndrome
d. cherry red spot
e. Mongolian spot
In 1940, Kassebach and Merritt described a male infant with a discolored
raised lesion on the extremity which rapidly grew and invaded the entire
left leg, scrotum, abdomen, and thorax. The infant also had a
consumptive thrombocytopenia resulting in low platelets. This disorder is
now known as Kassebach-Merritt syndrome. The disorder is known to be
associated with Kaposi hemangioendothelioma and thrombocytopenia . it
is believed that the hemangioma triggers a cycle of activation of the
coagulation cascade followed by the consumption of the clotting factors
and platelets. the activation of platelets and the release of the mediators
also causes growth of the vascular defect. C
3. A 22 yo has sea sickness and asks you for some medication.
You prescribe her a transdermal patch of?
a. Hismanal
b. chlorpromazine
c. metoclopramide
d. scopolamine
e. atropine
Scopolamine is a decent anti emetic agent and also prevents dizziness.
Sometimes is has also been used to treat abdominal cramps. In the past it
was frequently used as pre anesthetic agent and for prevention of motion
sickness. Today. Scopolamine is available as a patch which can be placed
behind the ear. It is useful in preventing travel and sea sickness. Many
scuba divers use scopolamine patches. There is evidence that
scopolamine may also have anti depressant effects. Individuals who have
glaucoma should be careful with scopolamine as it can precipitate attacks.
D
4. In which of the following cancer is the myc gene amplified?
a. small cell lung cancer
b. squamous cell of skin
c. actinic keratosis
d. carcinoid of small bowel
e. melanoma
The myc protein acts like a transcription factor and is known to control
several other genes. Mutations the myc gene have been founding several
cancers including lung, Burkett’s and B cell leukemia. The myc oncogenes
are known to become activated by may become activated by either an
arrangement or amplification process. Breakage and re sealing of the
chromosomes is part of the process and may affect many genes.
Translocation of gene is a process of rearrangement and can occur
between chromosomes, such as between chromosome 8 and 14. This
arrangement results in expression of the myc gene and eventually into a
B cell lymphoma. A
5. A 15 year old is seen in the hematology clinic with complaints
of fatigue. Examination reveals mild jaundice and splenomegaly.
Blood work reveals a CBC of 2.9, Hct of 22 and Hb of 8. The mean
corpuscular hemoglobin concentration is markedly increased. The
most likely cause is?
a. sickle cell anemia
b. Thalassemia
c. hereditary spherocytosis
d. iron deficiency anemia
e. macrocytic anemia
An increased MCHC obtained from an electronic cell counter is a
characteristic feature of red cells in HS. MCHC values greater than the
upper limit of normal (35-36%) are common. This increased MCHC is a
result of mild cellular dehydration. The mean cell volume (MCV) in
patients with HS actually is low. This relatively low MCV may reflect
membrane loss and cell dehydration.
Hereditary spherocytosis is a genetic disorder with autosomal dominance,
and is common in individuals from Northern Europe and Japan. Today,
estimates indicate that at least 25% of cases are due to spontaneous
mutations. With an autosomal dominant trait, there is chance that an
individual has a 50% chance of passing the disorder onto his/her offspring-
assuming that the partner does not carry the spontaneously mutated
gene. Hereditary spherocytosis causes defects in the genes that code for
proteins such as spectrin and ankyrin. These proteins are involved in the
formation and stabilization of red cell membranes. These proteins play a
major role in the maintenance of the shape of the RBC. In HS, it is ankyrin
which appears to be defective. The red cells formed are abnormal and
removed by the spleen. C
6. A 16 year old is admitted to the hematology clinic with
complaints of fatigue and joint pains. He has had RUQ pain on
numerous occasions which has subsided with pain medications.
Blood work reveals a hypochromic mild anemia and a blood smear
reveals intraerythrocytic crystals. Laboratory studies reveal that
these intraerythrocytic crystals disappear in the absence of
oxygen and appear when a slat solution (e.g. vinegar) is added.
He may have?
a. Thalassemia
b. Hemophilia
c. Von Willebrand disease
d. Idiopathic thrombocytopenic purpura
e. Hemoglobin C
f. Sickle cell anemia
g. Leukemia
The hemoglobin C cell forms circulating intraerythrocytic crystals
(tactoids) in the oxy state and has reduced solubility. In a deoxygenated
state, virtually all hemoglobin C cells have crystalloid inclusions.
Deoxygenation further reduces cell solubility and increases blood
viscosity. Add 3% salt solution to a drop of blood smear, and then the
crystals appear. Sickle-cell anemia is due to a mutation in the beta globin
chain of hemoglobin and the amino acid glutamic acid is replaced with
valine in the 6thposition. This lead to a mutation of the chain which
polymerizes under low oxygen tension causes the red cells to be distorted
and lose their elasticity. In fact the newer RBC are quite elastic and this
allows them to pass through the small size capillaries. However, with time
and low oxygen concentration, this elasticity is lost and the red cells
maintain the deformed shape- sickle cell. These deformed cells are then
removed by the spleen. When the deformed cells plug up a blood vessel,
ischemic episodes (sickle cell crises) occur. F
7. A 22 year old male presents with a history of discolored urine
and vague abdominal pain. He says he has had these symptoms
for more than a year. It is decided that a Ham test should be done
to rule out?
a. Thalassemia
b. sickle cell
c. aplastic anemia
d. paroxysmal nocturnal hemoglobinuria
e. hemophilia
f. iron deficiency anemia
g. leukemia
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disorder which is
typically presents with aplastic anemia, thrombosis and discolored urine
(red). The diagnosis in the past was done with the so called HAM test.
Today, advances in flow cytometry can help assess presence of CD55,
CD16 and CD59 on both the white and red blood cells. PNH is then
subclassifed depending on the presence of these CD markers. D
8. In 22 year old with a prolonged labor stage, the obstetrician
decides to use a drug to thin, dilate and ripen the cervix. The
agent is
a. Finasteride
b. oxytocin
c. ergonovine
d. progesterone
e. dinoprostone
f. aspirin
g. nitroglycerine
Dinoprostone works by causing the cervix to thin and dilate (open) and
the uterus to contract (cramp) the way it does during labor. E
9. A 65 yo female was seen in the clinic and brought her
abdominal x ray with her. She says that she has had a number of
episodic pain episodes in the RUQ associated with nausea and
vomiting. She kept on a fat free diet and subsequently she did
improve. She also has a radiology report which claims that she
has a rim of calcification around the entire gall bladder. You think
she may be at risk for?
a. Acalculous cholecystitis
b. Gall stone ileus
c. Cancer
d. Pancreatitis
e. Gall bladder fistula
f. Peptic ulcer disease
g. Duodenal perforation
h. Hepatitis
In some rare, the gall balder will form a calcified rim around it. This is
what is known as a porcelain gall bladder. There is some evidence that
porcelain gall gladder is a risk for cancer. Gall balder cancer is almost
spread before it is diagnosed. It generally spreads spread to nearby
organs and tissues such as the liver or small intestine. It also spreads
through the lymph system to lymph nodes in the region of the liver (portal
hepatis). Ultimately, other lymph nodes and organs can become involved.
The risk factors for gall bladder cancer are unknown. Although it occurs
most often in people with calcified or porcelain gall bladder-where
repeated inflammation from passing gallstones leads to hardening
(calcification) of the gall bladder, it is extremely rare even in such
patients. Since the gallbladder isn't essential, people with a calcified gall
bladder may consider having it removed as a preventative measure. C
10. A 2 year old thin male who smokes presents to the ER with
complaints of left sided chest pain. The pain came on suddenly
and he acutely became short of breath. In the ER his pulse
oximetry is 94% at room air. He most likely may have developed?
a.Gastric perforation
b.Pneumothorax
c.CHF
d.Pneumonia
e.Asthma
f.Emphysema
Spontaneous pneumothorax: Although some view primary spontaneous
pneumothorax as more of a nuisance than a major health threat, deaths
have been reported. Secondary spontaneous pneumothorax can be life
threatening, depending on the severity of the underlying disease and the
size of the pneumothorax. Compared with similar patients without
pneumothorax, age-matched patients with chronic obstructive pulmonary
disease have a 3.5-fold increase in relative mortality when a spontaneous
pneumothorax occurs. Mortality percentages in patients with chronic
obstructive pulmonary disease and spontaneous pneumothorax vary from
1-17%.
For a complete review on MCQs on USMLE, contact
nirihs01@hotmail.com
Posted by sbmedex at 8:31 PM 0 comments Links to this post
USMLE Step 1 Medicine & Surgery part 3
Please select one correct answer
1. A 35 yo is about to undergo an invasive medical procedure. She
tells you that she has Mitral valve prolapse. Which of the
following procedures does not require endocarditis prophylaxis?
a.elective C-section
b.upper endoscopy
c.cardiac catheterization
d.dental extraction
e.appendectomy
f.Congenital valve surgery
Antibiotic prophylaxis is recommended for all invasive respiratory tract
procedures that involve incision or biopsy of the respiratory mucosa (e.g.,
tonsillectomy, adenoidectomy). Antibiotic prophylaxis is not
recommended for bronchoscopy unless the procedure involves a biopsy.
When anti biotic prophylaxis is used, it should cover Streptococcus
viridians.
Patients who are about to undergo a surgical procedure that involves
infected skin, skin structure, or musculoskeletal tissue, should receive an
agent active against staphylococci and beta-hemolytic streptococci (e.g.,
antistaphylococcal penicillin, cephalosporin).
If the causative organism of respiratory, skin, skin structure, or
musculoskeletal infection is known or suspected to be Staphylococcus
aureus, one should start a antistaphylococcal penicillin or cephalosporin,
or vancomycin (if patient unable to tolerate beta-lactam antibiotics).
Vancomycin is recommended for known or suspected Methicillin-resistant
strains of S aureus.
Antibiotics are no longer recommended for endocarditis prophylaxis for
patients undergoing genitourinary or gastrointestinal tract procedures.
2. A 59 yo is involved in a car wreck is brought to the ER
intubated. He is resuscitated and admitted to the ICU because of
severe brain injury. His chest x ray reveals that he has bilateral
fluffy infiltrates. Which of the following is the earliest finding of
ARDs within 12-24 hours after the onset of the disorder?
a.Fluffy infiltrates on chest x-ray
b.Hypercapnia
c.Extreme hypoxia
d.Increased TV
e.Tachypnea
f.Fever
There are many physical signs that reflect lung pathology and other organ
injury associated with ARDS. However, the first physical sign of the
disorder is tachypnea. As pulmonary edema develops, the lung
compliance decreases and the tidal volume decreases towards the FRC
and the work of breathing increases. Patients will also become blue and
pale with time with increasing hypoxemia. Fever may be due to a ongoing
pneumonia, sepsis or may reflect a massive inflammatory process. All
patients with ARDs develop crackles in the lung fields. Other physical
signs may include the presence of an air leak, pneumothoraces,
pneumomediastinum, pneumopericardium, and subcutaneous
emphysema. As PEEP is increased the heart sounds will be muffled and
there will be signs of decreased cardiac output. E
3. A 71 yo requires mechanical ventilation because of respiratory
failure. Over the ensuing few days it is noticed that his
oxygenation is poor. The critical care physician decides to
increase the PEEP to 20 mmH20. The major effect of increasing
PEEP to such levels is?
a.Increasing venous return
b.Decreasing intracranial pressure
c.Increasing CO2 excretion
d.Decreasing PO2 levels
e.Decreasing cardiac output
The problem with PEEP is how much to give: insufficient PEEP is of little
benefit, excessive PEEP can cause three distinct problems:
Alveolar over distention in the upper part of the lungs is common.
Continued used of high PEEP can lead to barotrauma. Excessively high
alveolar pressures may narrow the capillaries which surround the
airspaces, causing an increase in dead space (wasted ventilation) and an
unnecessary increase in the work of breathing.
Increased intrathoracic pressure as a result of PEEP will reduce the
pressure gradient along which blood returns to the heart (flow is always
from zones of high pressure to those of low pressure, the negative
intrathoracic pressure associated with inspiration enhances this effect).
This reduces right ventricular preload, right ventricular output and
ultimately cardiac output. This may lead to a reduction in blood pressure
and pooling of blood in the abdomen and peripheries. Conversely, in
severe heart failure this may be beneficial. E
4. The revised trauma score incorporates which of the following:
a.Patient age and chronic medical conditions
b.Glasgow coma scale, respiration rate and blood pressure
c.Physiologic and metabolism problems
d.Number of fractures
e.Co morbidity conditions
f.Eye, motor and visual problems
The Revised Trauma Score is made up of a combination of results from
three categories: Glasgow Coma Scale, Systolic Blood Pressure, and
respiratory rate. All of these results can be quickly assessed with minimal
equipment: a flashlight, a watch and a sphygmomanometer since systolic
pressure can be obtained through arterial palpation. The score range is 0-
12. with a score of 12, the patient is stable, 11 reflects urgent
(intervention is required but the patient can wait a short time), and 10-3 is
IMMEDIATE (immediate intervention is necessary). The last possible label
is MORGUE, which is given to seriously injured people with an RTS score of
3 or lower. B
5. A female has first degree burns to her entire left arm, second
degree burn to the front of the chest, abdomen and third degree
circumferential burn to her left thigh and lower leg. The fluid
requirements are what percent of the total body?
a.36%
b.12%
c.72%
d.54%
e. 8%
Burns are judged by the size of the burn in relation to the whole body and
by the depth of the burn injury. Different methods exist to calculate the
extent or size of a burn injury. The most common method, which provides
a quick estimate of burn size, uses the "Rule of Nines," where the body is
divided into areas equaling multiples of 9% of the total body surface area.
The palm of your hand, for example, is equal to about 1% of your body's
surface area. The head and arms are each equal to 9% of the body
surface. The chest and back are each 18% (2 x 9%). Each leg is 18% (2 x
9%). This totals eleven nines, or 99%. The heads of infants and small
children are in relatively larger proportion to the total body surface area,
and the limbs are in relatively smaller proportion than adults limbs. The
total body surface area of a burn is referred to as TBSA, or total body
surface area. A patient might have the diagnoses of a 45% TBSA thermal
burn, for example. The TBSA and burn depth analysis are recorded on a
hospital chart known as a "burn diagram." Determining the percent of
body surface area burned is important for correct fluid resuscitation. A
6. A postoperative patient is given morphine for pain. Later he
develops nausea and is given an anti emetic. Soon he becomes
drowsy and has a respiration rate of 7/min. the next step in his
management is?
a. Send the patient to ICU
b. Observation
c. Dialysis to remove the anti emetic agent
d. Intubate and mechanically ventilation
e. Administer naloxone
f. Give 100% oxygen
g. Order arterial blood gas
h. Give an antidote to the anti emetic
Naloxone is a drug used to counter the effects of opioid overdose, for
example heroin or morphine overdose. Naloxone is specifically used to
counteract life-threatening depression of the central nervous system and
respiratory system. It is marketed under various trademarks including
Narcan, Nalone, and Narcanti, and has sometimes been mistakenly called
"naltrexate." No time should be wasted ordering redundant chest x rays or
blood gas. E
7. An 18 yo steps on a dirty nail and develops pain in his forefoot.
In the ER, he is examined and it is suspected that he may have
acquired tetanus. The first sign of a tetanus infection is?
a.Dysphagia
b.Stiff neck
c.Convulsions
d.Muscle pain
e.Redness
f.Pain
g.Fever
The first signs of tetanus infection are usually a headache and spasms of
the jaw muscles. The victim may become irritable. As the poison spreads,
it causes muscle spasms in the neck, arms, legs, and stomach. The victim
may get painful convulsions, which can be severe enough to cause broken
bones. People with tetanus may have to spend several weeks in the
hospital under intensive care. In the United States, a tetanus infection
carries a mortality of 30%. B
Posted by sbmedex at 8:23 PM 0 comments Links to this post
Labels: USMLE Medicine
USMLE step 1: Anti TB drugs/Pharmacology
Please select the one correct answer
1. The principal first line drugs for Mycobacterium tuberculosis
include all except:
a.Isoniazid
b.Ethambutol
c.Rifampin
d.Gentamycin
e.Pyrazinamide
All except Gentamycin are first line agents for tuberculosis because of
their efficacy and acceptable degrees of toxicity. D
2. Which of the following statement about Tuberculosis drugs is
false?
a.multi drug resistance is common
b.duration of treatment may range from 4-9 months
c.single drug therapy is effective for the majority of cases
d.side effects should be monitored
e.poor patient compliance also affects treatment
A minimum of two drugs should always be used for treatment and
sometimes even 3. This multi drug regimen is designed to prevent the
emergence of resistant strains. The regimen is continued until the clinical
disease has disappeared.
3. A 43 year old Asian is placed on Isoniazid for 4 months to treat
his TB. He comes to you with complains of painful tingling in his
arms and legs. The tingling has been getting intense on a daily
basis. The side effects of Isoniazid can be reversed with:
a.vitamin C
b.Niacin
c.Pyridoxine
d.Thiamine
e.Phenytoin
Peripheral neuritis is the most common adverse effect which is related to
a relative pyridoxine deficiency. Most of the toxic reactions are corrected
by pyridoxine (vitamin B6) supplementation.
4. A patient with TB is treated on a multi-drug regimen. Four
weeks later he presents with complaints of red colored tears. The
most likely agent causing this is:
a. Isoniazid
b. Gentamycin
c. Rifampin
d. Ethambutol
e. Pyrazinamide
Urine and feces as well as tears can be orange colored when taking
Rifampin. C
5. A 43 year old patient is seen in the eye clinic with complaints
of eye pain. His vision is blurred and the retinal exam does reveal
mild neuritis. Because the patient is an immigrant, you suspect
that the cause of his Optic neuritis is due to:
a.Ethambutol
b.Pyrazinamide
c.Rifampin
d.Isoniazid
e.Gentamycin
Ethambutol can cause optic neuritis, which results in decreased visual
acuity and loss of ability to discriminate between red and green. Visual
acuity should be periodically examined. A
6. The drug of choice to treat (Leprosy) Hansen’s disease is:
a.Dapsone
b.Erythromycin
c.Isoniazid
d.Gentamicin
Dapsone is structurally related to Sulfonamides. It is used also to treat
PCP. A
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Labels: USMLE Pharmacology
USMLE Step 1 & 2- Trauma and Medicine MCQs
Please select one correct answer
1.A 71 year old is admitted to the CCU and needs invasive
monitoring. It is decided to place a swan Ganz catheter and
measure the pulmonary catheter wedge pressure. This will allow
one to assess the pressure in the?
a. Right atrium
b. Left atrium
c. Left ventricle
d. Right ventricle
e. Aorta
f. Inferior vena cava
Pulmonary capillary wedge pressure (PCWP) provides an indirect estimate
of left atrial pressure (LAP). Although left ventricular pressure can be
directly measured by placing a catheter into the left ventricle by feeding it
through a peripheral artery, into the aorta, and then into the ventricle, it is
not possible to place the catheter into the left atrium unless there was an
atrial septal defect present. The swan Ganz catheter is usually inserted at
the bedside under sterile conditions. It is frequently used to monitor
patients in the CCU and ICU. B
2. A 64 year old male in the ICU needs quick IV access. The
resident decides to insert a central venous line. Which is not a
complication of right internal jugular puncture?
a. pneumothorax
b. hemomediastinum
c. thoracic duct injury
d. tracheal puncture
e. phrenic nerve injury
f. carotid artery dissection
g. injury to esophagus
Central line insertion can be associated with a number of complications.
However, the benefits derived from their benefits far overide the risks of
potential complications. The most common complication of central line
insertion is pneumothorax. There is a belief that the incidence of
pneumothorax is higher if the central line is attempted via the subclavain
vein. Many physicians utilize ultrasound to help identify the neck veins
before cannualtion. The reported incidece of penumothorax is about 1%
but this is unreported.
Other complications of central lines include infection chiefly from
Staphylococcus aureus and Staphylococcus epidermidis. The risk of
infection are high when the individual is diabetic, immunocomprmised and
obese. When a central line infection is suspected, the line should be
removed and the tip sent for culture. If the individual is febrile, blood
cultures should be obtained. No new line should be re inserted until the
cultures are negative or the fever has subsided. Other rare complications
of central lines include injury to the carotid artery, air embolism,
arrhythmias, pericardial tamponande and pain G
3.A 45 year old obese female undergoes a laparotomy for bowel
obstruction. The best way to manage her post operative pain is?
a. nurse controlled analgesia
b. pain medication prn
c. patient controlled analgesia
d. Epidural anesthesia
e. acupuncture
Patient controlled analgesia is best for most individuals esp. children and
obese individuals. C
4. A 57 year old has been told that he has a mass behind the left
knee. Ultrasound reveals that it is a vascular mass. In general,
the most common presentation of a popliteal artery aneurysm
begins with?
a. pain
b. mass behind knee
c. decreased pulses
d. claudication
e. sudden onset of left cold leg
Popliteal artery aneurysms (PAAs) are the most common peripheral
arterial aneurysms and the second most common aneurysm after
abdominal aortic aneurysms. In the past, popliteal aneurysms have been
associated with a high rate of limb loss. When the aneurysm ruptures,
there is a sudden loss of blood supply to the distal leg. In many cases,
embolization to the distal blood vessels of the foot is also common.
Because of this awareness, all individuals with either asymptomatic or
symptomatic aneurysms of ≥ 2 cm in diameter should be considered for
elective pass surgery. While surgery was the standard of care in the past,
this has no changed with the availability of endovascular therapy.
Endovascular stenting is also an excellent option in the presence of a
ruptured aneurysm. Once a stent has been placed it is important that the
patient be placed in anticoagulation medications like ticlodipine. E
5. A 35 yo female has just delivered a baby and 2 days later is
found to have a swollen left leg. Ultrasound shows a deep vein
thrombus just beneath the popliteal vein. The next step in her
management is?
a. coumadin
b. heparin loading then infusion
c. low molecular weight heparin
d. Aspirin
e. Green field filter
f. Compression stockings
g. ambulation
The primary aim for the treatment of DVT is to prevent pulmonary
embolism, reduce morbidity, and prevent or minimize the risk of
developing the postphlebitic syndrome. Anticoagulation is the mainstay of
the initial treatment for DVT. One may use either unfractionated heparin
or low molecular weight heparins to treat the DVT. Heparin does not lyse
the thrombus but prevents extension of thrombus. Heparin has been
shown to significantly reduce (but not eliminate) the incidence of fatal and
nonfatal pulmonary emboli as well as recurrent thrombosis. The chief
reason for the continuing risk of PE is mainly because heparin does not
affect the preexisting nonadherent thrombus. Heparin does not affect the
size of existing thrombus nor does it have any intrinsic thrombolytic
activity.
In less than 10% of patients is heparin therapy associated with complete
lysis. Heparin therapy has little effect on the risk of developing the
postphlebitic syndrome. The deep vein thrombus usually causes
destruction of the valves which almost always results in a high incidence
of chronic venous insufficiency and postphlebitic syndrome.
Warfarin therapy is usually started 3-5 days after heparin. The INR is
maintained anywhere between 2-2.5. Heparin must be overlapped with
oral warfarin because of the initial transient hypercoagulable state
induced by warfarin. This effect is related to the differential half-lives of
protein C, protein S, and the vitamin K–dependent clotting factors II, VII,
IX, and X. Long-term anticoagulation is definitely indicated for patients
with recurrent venous thrombosis and/or persistent or irreversible risk
factors. B
6. A 20 year old was involved in a motor vehicle accident. He had
severe blunt chest trauma to the chest. In the ER he received 8
units of packed red blood cells. Soon after he became short of
breath and his PO2 was 55 on 100% oxygen. His chest x ray
revealed a complete white out and he had a Central venous
pressure of 11. At 48 hours after the injury, the nature of his lung
injury was most likely due to?
a. pulmonary contusion
b. ARDs
c. Pneumonia
d. PE
e. heart failure
f. lung fibrosis
Brusing or contusion of the lug is common after chest trauma. The
condition results in lng unjury hwhcih is often marked by fluid and blood
sccumualtion in th elung parenchyma. This results in difficutly in
oxygenation and hyperventilation. In lung contuison the lung tissue
structure is intact and there is no franck terar or rupture. Pulmonary lung
contuion rarely occurs in isolation iand is often associated with rib
fractures or soft tissue injury. The typical signs of lun contusion incldue
chest pain, fever, tachyonea and hemoptysis. The chest x ray may reveal
signs of a lung contuison, but a CT scan is required for a definitive
diagnosis. A
7. A 43 yo is involved in a car accident and breaks both femurs.
There is concern that he may develop fat embolism syndrome.
The radiographic findings of fat embolus are most typically
evidenced at what time period?
a. 0-12 hrs
b. 12-24 hrs
c. 24-48 hrs
d. 48-72 hrs
e. immediately
There is no radiological feature which is diagnostic of fat embolism
syndrome. Infact in the first few hours after injury, the chest x ray may be
completely normal. Over the next 48 hours, some patients may develop
bilateral fluffy shadows which are associated with a decline in the
respiratory status. Some individuals may develop diffuse or patchy air
space consolidation, due to edema or alveolar hemorrhage; this is most
prominent in the periphery and bases. Radiological studies like the
Ventilation/perfusion scans may demonstrate a mottled pattern of sub-
segmental perfusion defects with a normal ventilator pattern. In most
cases, the earliest features on x ray may be seen around 48-72 hours.
CT may identify ill defined areas of centrilobular and sub pleural nodules
representing alveolar edema, microhemorrhage, and inflammatory
response secondary to ischemia and cytotoxic emboli may be seen. MRI of
the brain may reveal high-intensity T2 signals; this correlates with the
degree of neurological impairment found clinically.
Fat particles are not present in more than 50% of individuals with fat
embolism syndrome. There are some who advocate the use of
bronchoscopy with bronchoalveolar lavage to detect fat droplets in
alveolar macrophages as a means to diagnose fat embolism has been
described in trauma patients and patients with the acute chest syndrome
of sickle cell disease. However, diagnostic criteria vary and the sensitivity
and specificity are unknown. D
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Labels: USMLE Trauma
USMLE Step 1 and 2, Medicine and Pharmacology
Please select one correct answer
1.A 30 yo black female presents with a 4 month history of a dry
cough and general malaise. She does not smoke and her TB skin
test was negative. She did have an episode of renal colic 2 weeks
ago. Her x ray shows some mediastinal widening near the hilum
area. She may have?
a.HIV
b.Lobar pneumonia
c.Churg Strauss
d.Sarcoidosis
e.Pericardial tamponade
f.Pneumothorax
g.PCP
h.Aortic dissection
Sarcoidosis is a disorder of unknown etiology. It tends to occur more
commonly in black females and is characterized by non-caseating
granulomas. The disease may only affect the lung but can be widespread
and affect the entire body. Most people have no symptoms. Sarcoid
typically presents on X ray as mediastinal adenopathy and needs to be
differentiated from TB. The classic symptoms of sarcoid include loss of
energy, lethargy, generalized myalgias and arthralgia, dry and burning
eyes, shortness of breath, a dry cough etc. some individuals may develop
erythema nodosum or a skin rash. Blood work in individuals with
sarcoidosis will reveal hypercalcemia and elevated vitamin D levels. When
sarcoidosis presents with erythema nodosum, bilateral hilar adenopathy
and arthralgia, this is known as Lofgren syndrome. Most patients have a
good prognosis after the diagnosis. Sarcoid is essentially a systemic
disorder and can affect the eye which can cause blindness. When the
parotid gland and eye are affected in individuals with sarcoidosis, this is
known as Heerfordt-Waldenstrom syndrome.
2. A 22 year old is admitted because of a coagulopathy. He says
he has a tendency to bleed and his brother died from the
disorder. Blood work reveals a PT of 12.4 s, PTT of 38 s, INR 1.2,
platelets 311 and a normal bleeding time. The platelet
aggregation test reveals lack of GP2B/3A. Of the following
disorders he most likely has
a.Bernard Soulier
b.hemophilia
c.protein C deficiency
d.glanzmann’s thrombasthenia
e.von willebrand’s
Glanzmann's thrombasthenia is a very rare disorder and acquired via an
autosomal recessive trait. The platelets formed lack the GP2B/3A
receptor, thus preventing the platelet from aggregating together. Despite
normal level of platelets the bleeding time is prolonged. D
3. In which coagulopathy will one see a significant level of d
dimers?
a.hypothermia
b.DIC
c.MI
d.Bernard soulier
e.use of Ticlid
Disseminated intravascular coagulation (DIC) is a pathological process
where by the blood coagulation system goes havoc. The coagulation
cascade is activated continuously and the platelets are used up. The
disorder typically occurs in sick and critically ill patients. The usual cause
is an infection- particular gram negative sepsis. The blood work usually
reveals low levels of platelets, and elevated levels of fibrin degradation
products and D dimer. The bleeding time is prolonged. DIC- d dimers B
4. A 55 year old is found to have the translocation of the Bcr/abl
gene. The most likely defect he has is
a.Hodgkin’s
b.CML
c.CLL
d.burkitt’s
e.non Hodgkin’s
The Philadelphia chromosome involves translocation between
chromosome 9 and 22. The Bcr/abl gene is involved in this translocation.
The Philadelphia chromosome is commonly seen in chronic myelogenous
leukemia. The complete absence of the Philadelphia chromosome
indicates a very poor prognosis. The Philadelphia chromosome is also
seen in ALL and AML but to a lower degree. B
5. A 59 yo is admitted with chest pains. He is started in an IV NTG
drip. The rapid heart rate sometimes seen after nitroglycerin
administration is best explained by:
a. direct effect on the heart
b. reflex sympathetic discharge due to a fall in systemic blood pressure
c. due to release of norepinephrine from sympathetic nerve endings
d. inhibition of cholinergic activity on the heart
Nitroglycerine decreases blood pressure and causes a reflex tachycardia.
B
6 Digoxin is useful in atrial fibrillation because it:
a. slows the sinus node activity
b. stimulates cholinergic activity
c. slow conduction through the A-V node
d. blocks the norepinephrine response to the heart
e. decreases the rate of conduction through atrial muscle
Digoxin acts at the AV node. C
7. When digitalis therapy is initiated, serious cardiac arrhythmias
may be caused by a deficiency of:
a. Sodium
b. Potassium
c. Chloride
d. Bicarbonate
e. Uranium
Potassium and magnesium deficiency are both known to worsen digoxin
toxicity. B
8 Digitalis toxicity manifested by premature ventricular
contractions may
be treated with all of the following EXCEPT:
a. Lidocaine
b. Digitalis-specific immune FAB antibody
c. Phenytoin
d. Quinidine
e. Potassium replacement
Lidocaine is of no benefit in treatment of digoxin toxicity.
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Labels: USMLE Step 1 Review 1
USMLE Step 1- Physiology
Please select the one correct answer
1. Which of the following is false about bombesin?
a. it is an autocrine growth factor
b. it is found in the gi tract
c. contracts gall bladder
d. releases pancreatic enzymes
e. functions as an endocrine hormone
A peptide that is found in the intrinsic nerves of the gastrointestinal tract,
bombesin stimulates the release of gastrin and pancreatic enzymes and
causes contraction of the gallbladder. These functions may be secondary,
however, to the release of cholecystokinin, a hormone secreted by the
mucosa of the intestine that has similar effects. E
2. Which lung cancer is commonly associated with hypercalcemia?
a. small cell
b. squamous cell
c. adenocarcinoma
d. carcinoid
e. bronchoalveolar
Humoral hypercalcemia of malignancy, resulting from the production of
parathyroid hormone-related protein by the tumor, is most commonly
associated with squamous cell carcinoma. B
3. Which lung cancer is most commonly associated with the
SIADH SYNDROME?
a. Squamous cell
b. Carcinoid
c. Small cell
d. Adenocarcinoma
The SIADH is also more common in small cell carcinoma, occurring in 7%
to 11% of patients. The manifestations of hyponatremia (mental status
changes, lethargy, or seizures) are often absent despite very low sodium
levels, as the rate of decline is typically prolonged. C
4. In ethanol drinking, the typical enzymatic pattern of liver
enzymes is?
a. AST> ALT
b. ALT> AST
c. elevated alkaline phosphatase
d. elevated bilirubin
Diagnosing ALD is a challenge. A history of heavy alcohol use along with
certain physical signs and positive laboratory tests for liver disease are
the best indicators of disease. Alcohol dependence is not necessarily a
prerequisite for ALD, and ALD can be difficult to diagnose because
patients often minimize or deny their alcohol abuse. Even more
confounding is the fact that physical exams and lab findings may not
specifically point to ALD. Diagnosis typically relies on laboratory tests of
three liver enzymes: gamma–glutamyltransferase (GGT), aspartate
aminotransferase (AST), and alanine aminotransferase (ALT). Liver
disease is the most likely diagnosis if the AST level is more than twice that
of ALT, a ratio some studies have found in more than 80 percent of
alcoholic liver disease patients. An elevated level of the liver enzyme GGT
is another gauge of heavy alcohol use and liver injury. Of the three
enzymes, GGT is the best indicator of excessive alcohol consumption, but
GGT is present in many organs and is increased by other drugs as well, so
high GGT levels do not necessarily mean the patient is abusing alcohol. A
5. Parafollicular cells of the thyroid secrete:
a. Calcitonin
b. Amyloid
c. Thryoglobulin
d. Parathyroid hormone
e. Iodine
Parafollicular cells also called C cells, are cells in the thyroid which
produce and secrete calcitonin. A
For more USMLE Questions, write to nirihs01@hotmail.com.
500 questions for $10.
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Labels: USMLE MCQs Physiology
S U N D A Y , F E B R U A R Y 8 , 2 0 0 9
USMLE Review step 1 MCQs
1. A 10 year old girl is seen in the neurology clinic with
complaints of severe burning pain in her extremities and ongoing
fever that has been going on for years. Her mother says that the
physician told her it was a congenital problem. Examination also
reveals the presence of numerous dark skin lesions over the
lower trunk. Biopsy of the lesions reveals an excess of ceramide.
She most likely has:
a. gaucher’s
b. tay sachs
c. lesch nynn
d. fabrys
e. hurler’s
X-Linked Recessive. alpha-Galactosidase A deficiency leads to a buildup of
ceramide trihexoside in body tissues.. Angiokeratomas (skin lesions) occur
in the lower trunk, fever, severe burning pain in extremities. Fabry's
disease is also be associated with involvement of the cardiac and brain
organs. Other symptoms include decreased sweating, tiredness and
angiokeratomas.
Angiokeratomas are small, painless skin lesions that may appear on any
region of the body, but are most common on the legs, abdomen and groin
area. Often the eyes are involved and causes keratopathy. other eye
lesions include cataracts, papilledema, optic atrophy and mecualr
swelling. D
2. Deficiency of adenosine deaminase is seen in?
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. Jobs
Autosomal Recessive. Adenosine Deaminase deficiency leads to
accumulation of dATP. This leads to a decrease in DNA precursors
molecules. Severe deficiency in both humoral and cellular immunity
occurs due to impaired DNA synthesis. Bone marrow transplant may be
helpful in treatment. B
3. The most common type of immune deficiency in children is?
a. AIDs
b. DiGeorge
c. Selective IgA
d. SCID
e. CGD
The most common congenital immune deficiency is selective IgA. There
also exists selective IgM and IgG deficiencies, but they are less common.
IgA deficiency may be due to a failure of heavy-chain gene switching.
4. A 43 yo female with a dilated cardiomyopathy suddenly
developed this rhythm. The patient has a BP of 50/10 and the
pulse is very weak. You are on call to the Medical Floor and the
nurse asks you to do something quick. Please look at the
attached link and decide that the best treatment is?
a. beta blocker
b. quinidine
c. amiodarone
d. digoxin
e. Defibrillation
Amiodarone is an anti arrhythmic drug used for various types of
tachyarrhythmias, both ventricular and supraventricular (atrial)
arrhythmias. it is a superb drug which can immediately reverse atrial
fibrillation and is also helpful for ventricular tachycardias. However, in any
patient with low blood pressure and a rhythm which is shown (VF), urgent
defibrillation is required. The first treatment of choice in a patient with
ventricular tachycardia is defibrillation at 360 joules. E
5. A 19 yo with no symptoms had this ECG before a work out. He
most likely has:
a. first degree HBb.
b. atrial flutter
c. Normal sinus rhythm
d. atrial fibrillation
e. ventricular arrhythmia
f. torsades de pointes
This is normal sinus rhythm. C
6. A 43 yo with mitral stenosis is found to have a dilated left
atrium. His rhythm strip is shown below. He most likely has?
a. atrial flutter
b. premature atrial beats
c. first degree heart block
d. atrial fibrillation
e. ventricular tachycardia
f. sinus tachycardia
Atrial fibrillation is common with advancing age; however other causes
include uncontrolled hypertension, coronary disease, CHF, valvular heart
disease, acute pulmonary processes, hyperthyroidism, acute alcohol
intoxication . Patients having undergone cardiac, pulmonary, or
esophageal surgery have a 20-40% postoperative incidence of atrial
fibrillation (AF). Patients with congenital heart disease are at higher risk
for developing AF. The most common arrhythmia seen in patients with
mitral stenosis is atrial fibrillation. The dilated atrium also has a tendency
to form a clot which frequently embolizes. if you see an ECG without any P
waves, irregular heart rate with narrow QRS, it is Atrial fibrillation until
proven otherwise. D
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Labels: Medicine, Pharmacology, Physiology, USMLE MCQs
S A T U R D A Y , F E B R U A R Y 7 , 2 0 0 9
USMLE Step 1 Review (a)
1. An angiogram reveals stenosis of the right innominate artery.
The artery can best be exposed by a?
a. right thoracotomy
b. right supraclavicular incision
c. median sternotomy
d. neck incision
Innominate artery is best exposed by a median sternotomy. the right
innominate artery gives off the right subclavian and the right common
carotid artery. C
2. A patient with a traumatic aortic rupture undergoes aortic
repair. The patient presents with hoarseness after surgery. The
most likely cause of hoarseness is?
a. postoperative viral infection
b. damage to phrenic nerve
c. trauma to recurrent laryngeal nerve
d. injury to sympathetic chain
e. damage to vocal cords during intubation
Hoarseness is due to injury to the recurrent laryngeal nerve. The recurrent
nerve runs in between the left common carotid and the left subclavian
and can easily be injured by placing a clamp in that region. C
3. A 35 year old male is involved in a head on motor vehicle
accident. On arrival to the emergency room, he has severe
bruises to his chest but is otherwise stable. The chest X ray
reveals a widen mediastinum. An angiogram is ordered which
reveals a traumatic aortic rupture. The most common site of
aortic rupture after severe blunt trauma to the chest is ?
a. ascending aorta
b. abdominal aorta
c. aortic arch
d. descending aorta distal to left subclavian artery
e. femoral artery
f. left common carotid artery
Following blunt trauma, the descending aorta just distal to the left
subclavian artery is most prone to injury. A chest x ray will reveal a widen
mediastinum and a CT scan is required for diagnosis. D
4. A new born is seen in the infectious disease clinic due to
repeated candida infections. Blood work reveals that he has very
low levels of calcium and has suffered from numerous tetany
spells. He most likely has:
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. renal failure
T-Cell deficiency occurs when the thymus is absent. Hypocalcemic tetany
occurs from primary parathyroid deficiency. In Digeorge syndrome, the
parathyroid and thymus glands are missing. C
5. Failure to develop the 3 and 4th pharyngeal pouches are linked
to what immune disorder?
a. AIDs
b. SCIDs
c. DiGeorge
d. CGD
e. Job’s
Failure of development of the 3rd and 4th Pharyngeal Pouches leads to
agenesis of the thymus and parathyroid glands. C
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Labels: AIDs, DiGeorge syndrome, parathyroid, SCIDs, thymus
USMLE Step 1 Review
1. The first branch of the aorta is?
a. right brachiocephalic artery
b. left common carotid
c. left subclavian artery
d. right coronary artery
e. right common carotid artery
The right coronary is the first branch of the aorta. D
2. A patient has been involved in a MVA. He presents to the
emergency room with severe pain in his right chest. The chest x
ray reveals numerous rib fractures and pulmonary contusion.
Which finding on the physical examination would make you
suspect that would make you suspect flail chest is?
a. difficulty breathing
b. increased stridor
c. paradoxical breathing
d. low oxygen saturation
e. pain
f. hyperventilation
Paradoxical breathing is a sin que non of flail chest. These patients need
arterial blood gas monitoring, pain control and pulmonary care. C
3. The main reason a tracheostomy is not performed on the first
cartilage ring is because:
a. trachea is too narrow
b. a high chance of subglottic stenosis
c. a high chance of tracheo-innominate artery fistula
d. inability to access it
e. technically impossible
f. chance of damaging esophagus
Tracheostomy performed in the first cartilage ring can result in subglottic
stenosis, which is almost impossible to repair. B
4. The most common mass in the anterior mediastinum is ?
a. thymoma
b. thyroid
c. Teratoma
d. lymphoma
e. leukemia
f. seminoma
Thymoma is the most common mass of the anterior mediastinum. A
5. The left lateral border and apex of the cardiac silhouette is
made up by the
a. right atrium
b. right ventricle
c. left atrium
d. left ventricle
The left ventricle makes up the major border of the left cardiac silhouette.
D
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Labels: USMLE Step 1 Review 1
PASS the USMLE: USMLE Surgery MCQs Step 1 & 2 (1)
PASS the USMLE: USMLE Surgery MCQs Step 1 & 2 (1)
Posted by sbmedex at 12:43 PM 0 comments Links to this post
USMLE Surgery MCQs Step 1 & 2 (1)
1. A postoperative patient is given morphine for pain. Later he
develops nausea and is given an anti emetic. Soon he becomes
drowsy and has a respiration rate of 7/min. the next step in his
management is?
a. send the patient to ICU
b. observation
c. dialysis to remove the anti emetic agent
d. intubate and mechanically ventilation
e. administer naloxone
f. give 100% oxygen
g. order arterial blood gas
i. give an antidote to the anti emetic
Naloxone is a drug used to counter the effects of opioid overdose, for
example heroin or morphine overdose. Naloxone is specifically used to
counteract life-threatening depression of the central nervous system and
respiratory system. It is marketed under various trademarks including
Narcan, Nalone, and Narcanti, and has sometimes been mistakenly called
"naltrexate." No time should be wasted ordering redundant chest x rays or
blood gas. E
2. An 18 yo steps on a dirty nail and develops pain in his forefoot.
In the ER, he is examined and it is suspected that he may have
acquired tetanus. The first sign of a tetanus infection is?
a. dysphagia
b. stiff neck
c. convulsions
d. muscle pain
e. redness
f. pain
g. fever
The first signs of tetanus infection are usually a headache and spasms of
the jaw muscles. The victim may become irritable. As the poison spreads,
it causes muscle spasms in the neck, arms, legs, and stomach. The victim
may get painful convulsions, which can be severe enough to cause broken
bones. People with tetanus may have to spend several weeks in the
hospital under intensive care. In the United States, a tetanus infection
carries a mortality of 30%. B
3. A 33 yo male with HIV presents with confusion and general
malaise. Blood work reveals that he is anemic and a CT scan
shows that he has generalized brain atrophy. The most common
type of HIV disorder of the brain is?
a. myelopathy
b. aseptic meningitis
c. AIDs dementia complex
d. Peripheral neuropathy
e. Encephalitis
f. Nocardia infection
g. cryptococcus
AIDS dementia complex (ADC; also known as HIV dementia, HIV
encephalopathy is a common neurological disorder associated with HIV
infection and AIDS. It is believed to be a metabolic encephalopathy
induced by HIV infection and involves interaction of the immune system.
These infected brain cells secrete a variety of neurotoxins which continue
to worsen the situation. The essential features of ADC are disabling
cognitive impairment accompanied by motor defects, improper speech
problems and a change in behavior. Most of the individuals show poor
memory, inability to concentrate and have mental clouding. The Motor
symptoms may include a loss of fine motor control which eventually leads
to inability to hold things, poor balance and recurrent tremors. Behavioral
alterations are significant and often include apathy, lethargy and flat
emotional responses and no spontaneity. Histopathologically, the brain is
infiltrated with monocytes and macrophages into the central nervous
system (CNS). there is gliosis, pallor of myelin sheaths, abnormalities of
dendritic processes and neuronal apoptosis. ADC typically occurs after
many years of HIV infection and is associated with low CD4+ T cell levels
and high plasma viral loads. It is sometimes seen as the first sign of the
onset of AIDS. Prevalence is between 10-20% in Western countries.
4. A 43 year old male is seen in the anesthesia clinic before his
Lasik procedure. However, he does mention during the
preoperative assessment that he has been passing bright red
blood per rectum. The next step in his management is?
a. complete the Lasik surgery and the refer to gastroenterology
b. remove the hemorrhoids
c. cancel the Lasik surgery and order a upper endoscopy
d. cancel surgery and order a colonoscopy
e. perform a rectal exam
f. do the Lasik and hemorrhoid surgery at the same time
Lasik is an elective procedure. Anytime an individual has another medical
problem, the elective surgery should be canceled. This 43 year old male
may have hemorrhoids but bright red blood per rectum should always be
investigated. In this age group, a rectal exam is a must. In the older age
group, a colonoscopy or a barium enema is highly recommended E.
5. A 54 year old undergoes a laparotomy for bowel obstruction.
The surgery is uneventful and only requires resection of an
adhesive band. Postoperatively on the first day the patient
develops a fever. The fever is most likely due to:
a. atelectasis
b. abscess collection
c. pneumonia
d. urinary tract infection
e. Deep vein thrombosis
f. Drug related
The most common cause of early fever post operatively is atelectasis. The
primary complication of atelectasis is hypoxemia, which is usually
transient. Within 24-48 hours, the lung area collapses and fails to be
ventilated. This is probably caused by a whole host of chemicals like
serotonin, histamine, prostaglandins, etc.The associated lung collapse is
always followed by profound vasoconstriction in the lung. If the atelectasis
is severe, it may cause enough hypoxemia acutely to require
supplemental oxygen or inhaler/ventilatory support.
Atelectasis is a suggested cause of fever in the early postoperative period.
However, all fever early in the post operative period is not always due to
atelectasis. Patients with temperatures of more than 38.5°C were less
likely to have atelectasis on radiography findings than those patients who
were afebrile and undergoing radiography as part of the postoperative
routine. A
Posted by sbmedex at 12:20 PM 0 comments Links to this post
Labels: 1, USMLE surgery
USMLE Surgery MCQs- Step 1 & 2
1. A 35 yo is about to undergo an invasive medical procedure. She
tells you that she has Mitral valve prolapse. Which of the
following procedures does not require endocarditis prophylaxis?
a. elective C-section
b. upper endoscopy
c. cardiac catheterization
d. dental extraction
e. appendectomy
f. congenital valve surgery
Antibiotic prophylaxis is recommended for all invasive respiratory tract
procedures that involve incision or biopsy of the respiratory mucosa
(e.g.,tonsillectomy, adenoidectomy). Antibiotic prophylaxis is not
recommended for bronchoscopy unless the procedure involves a biopsy.
When anti biotic prophylaxis is used, it should cover Streptococcus
viridans.
Patients who are about to undergo a surgical procedure that involves
infected skin, skin structure, or musculoskeletal tissue, should receive an
agent active against staphylococci and beta-hemolytic streptococci (e.g.,
antistaphylococcal penicillin, cephalosporin). If the causative organism of
respiratory, skin, skin structure, or musculoskeletal infection is known or
suspected to be Staphylococcus aureus, one should start a
antistaphylococcal penicillin or cephalosporin, or vancomycin (if patient
unable to tolerate beta-lactam antibiotics). Vancomycin is recommended
for known or suspected Methicillin-resistant strains of S aureus. Antibiotics
are no longer recommended for endocarditis prophylaxis for patients
undergoing genitourinary or gastrointestinal tract procedures. B
2. A 59 yo is involved in a car wreck is brought to the ER
intubated. He is resuscitated and admitted to the ICU because of
severe brain injury. His chest x ray reveals that he has bilateral
fluffy infiltrates. Which of the following is the earliest finding of
ARDs within 12-24 hours after the onset of the disorder?
a. fluffy infiltrates on chest x-ray
b. hypercapnia
c. extreme hypoxia
d. increased TV
e. Tachypnea
f. fever
There are many physical signs that reflect lung pathology and other organ
injury associated with ARDS. However, the first physical sign of the
disorder is tachypnea. As pulmonary edema develops, the lung
compliance decreases and the tidal volume decreases towards the FRC
and the work of breathing increases. Patients will also become blue and
pale with time with increasing hypoxemia. Fever may be due to a ongoing
pneumonia, sepsis or may reflect a massive inflammatory process. All
patients with ARDs develop crackles in the lung fields. Other physical
signs may include the presence of an air leak, pneumothoraces,
pneumomediastinum, pneumopericardium, and subcutaneous
emphysema. As PEEP is increased the heart sounds will be muffled and
there will be signs of decreased cardiac output. E
3. A 71 yo requires mechanical ventilation because of respiratory
failure. Over the ensuing few days it is noticed that his
oxygenation is poor. The critical care physician decides to
increase the PEEP to 20 mmH20. The major effect of increasing
PEEP to such levels is?
a. Increasing venous return
b. Decreasing intracranial pressure
c. Increasing CO2 excretion
d. Decreasing PO2 levels
e. Decreasing cardiac output
The problem with PEEP is how much to give: insufficient PEEP is of little
benefit, excessive PEEP can cause three distinct problems:
1. Alveolar over distention in the upper part of the lungs is common.
Continued used of high PEEP can lead to barotrauma.
2. Excessively high alveolar pressures may narrow the capillaries which
surround the airspaces, causing an increase in dead space (wasted
ventilation) and an unnecessary increase in the work of breathing.
3. Increased intrathoracic pressure as a result of PEEP will reduce the
pressure gradient along which blood returns to the heart (flow is always
from zones of high pressure to those of low pressure, the negative
intrathoracic pressure associated with inspiration enhances this effect).
This reduces right ventricular preload, right ventricular output and
ultimately cardiac output. This may lead to a reduction in blood pressure
and pooling of blood in the abdomen and peripheries. Conversely, in
severe heart failure this may be beneficial. E
4. The revised trauma score incorporates which of the following:
a. patient age and chronic medical conditions
b. Glasgow coma scale, respiration rate and blood pressure
c. Physiologic and metabolism problems
d. Number of fractures
e. Co morbidity conditions
f. Eye, motor and visual problems
The Revised Trauma Score is made up of a combination of results from
three categories: Glasgow Coma Scale, Systolic Blood Pressure, and
respiratory rate. All of these results can be quickly assessed with minimal
equipment: a flashlight, a watch and a sphygmomanometer since systolic
pressure can be obtained through arterial palpation. The score range is 0-
12. with a score of 12, the patient is stable, 11 reflects urgent
(intervention is required but the patient can wait a short time), and 10-3 is
IMMEDIATE (immediate intervention is necessary). The last possible label
is MORGUE, which is given to seriously injured people with an RTS score of
3 or lower. B
5. A female has first degree burns to her entire left arm, second
degree burn to the front of the chest, abdomen and third degree
circumferential burn to her left thigh and lower leg. The fluid
requirements are what percent of the total body?
a. 36%
b. 12%
c. 72%
d. 54%
e. 8%
Burns are judged by the size of the burn in relation to the whole body and
by the depth of the burn injury. Different methods exist to calculate the
extent or size of a burn injury. The most common method, which provides
a quick estimate of burn size, uses the "Rule of Nines," where the body is
divided into areas equaling multiples of 9% of the total body surface area.
The palm of your hand, for example, is equal to about 1% of your body's
surface area. The head and arms are each equal to 9% of the body
surface. The chest and back are each 18% (2 x 9%). Each leg is 18% (2 x
9%). This totals eleven nines, or 99%. The heads of infants and small
children are in relatively larger proportion to the total body surface area,
and the limbs are in relatively smaller proportion than adults limbs. The
total body surface area of a burn is referred to as TBSA, or total body
surface area. A patient might have the diagnoses of a 45% TBSA thermal
burn, for example. The TBSA and burn depth analysis are recorded on a
hospital chart known as a "burn diagram." Determining the percent of
body surface area burned is important for correct fluid resuscitation. A