Case 1

A young lady rushes into the Emergency Department, carrying her 3-year-old child, who experienced an acute onset of shortness of breath while eating peanuts. The child is coughing and crying, and struggling to breath. He appears agitated with a reddened face. His birth, developmental, medical, and surgical history are unremarkable, with no hint of respiratory issues prior to the current episode, nor is there a history of allergy of any type. The mother smokes, though she emphasizes that her smoking is occasional and outside the house.

On Physical Examination:Vital signs: Blood Pressure 130/90, Pulse 102/min, Respiratory rate 45/min, Temperature 98 degrees F (36.67 degrees C)Head and Neck: Nasal faring, reddish facial complexion, slightly cyanotic lips, Pink oral and air way, Nose was clear from internal obstruction or defect and cotton puff test was positive indicating patencyCardiovascular: S1+S2, no added soundsRespiratory: Sternal costal retractionChest: Auscultation of chest revealed stridor and expiratory wheezeA delay in treatment can result in which of the following? (Choose up to 4)

Your Answer Correct Answer

A. Bronchial stricture A. Bronchial stricture

B. Obstructive emphysema B. Obstructive emphysema

C. Cardiac arrest F. Lung abscess

D. Asphyxia H. Chronic postoperative pneumonia

DETAILED ANSWERS AND EXPLANATIONThe child's age, history, and examination suggest aspiration of a tracheobronchial foreign body (TFB), in this case a piece of a peanut, which has lodged in the airway. Children, ages 1-3 years, are at particular risk for foreign body aspiration, due to a tendency to put things into their mouths, and to chew food inadequately. Since this child developed symptoms suddenly while eating a small item, and since he has no history of allergic or respiratory conditions, the cough, expiratory wheeze, stridor, and left sternal coastal retraction, suggest TFB aspiration, rather than an allergic reaction to peanuts.

After obtaining vital signs and carrying out history and examination, initial supportive therapy for TFB aspiration includes oxygen administration, cardiac monitoring, pulse oximetry, and insertion of an intravenous line. Definitive airway management may be required as well.

After supporting the patient, a chest X-ray is warranted (P-A and lateral views).

CT scanning provides better detail of the foreign body and its location compared with flat film radiography, but usually is not included in the initial workup.

Perform standard posteroanterior inspiratory chest radiography to look for unilateral hyperinflation of the contralateral lung, hypoinflation of the ipsilateral lung, lobar or segmental atelectasis, mediastinal shift, pneumomediastinum, viewing of the foreign body, or air trapping. Complete obstruction of one side causes absorption of air on that side, resulting in hypoinflation and causes extra accumulation of air on the opposite side, and thus hyperinflation. These reactions, in turn, can cause mediastinal shift toward the affected side. In the case of partial obstruction, air will enter, but will exit with difficulty, thus trapping air. Lobar and segmental atelectasis, a condition in which there is a lack of gas exchange within alveoli due to alveolar collapse, is a result of complete obstruction. In chronic atelectasis, the blocked, contracted lung may develop pneumonia that fails to resolve completely and leads to chronic inflammation and scaring.

In 52 percent of cases, foreign bodies are in the mainstem of the right bronchus, 18 percent are in the mainstem of the left bronchus, 13 percent are in the trachea, 6 percent are in the right lower lobe bronchus, 5 percent are in the left lower lobe bronchus, 3 percent are in the larynx, and fewer than 1 percent are in the right middle lobe bronchus. Additionally, 2 percent of cases are bilateral. The main right bronchus is the main site of obstruction, because it is wider, shorter, and more vertical than the left bronchus.

After the initial, supportive measures, the foreign body must be extracted. If lodged below the vocal cords, but above the cricoid ring, the foreign body may be removed using Magill forceps, guided by laryngoscopy. If the patient is stable, intubation may not be necessary. If the patient is unstable, however, intubation is indicated, and the foreign body is removed using the Magill forceps along with suction. If the foreign body is located below the cricoid ring, intubation is indicated, whether or not the patient is stable. Then, bronchoscopy is performed under general anesthesia. If the first attempt is unsuccessful, it is repeated, but if the procedure fails a second time thoracotomy is necessary. Delay in treatment can result in the following conditions:

· Obstructive emphysema

· Atelectasis

· Tracheoesophageal fistula

· Bronchial stricture

· Pneumonia

· Persistent cough

· Hemoptysis

· Polyp formation

· Localized bronchiectasis

· Chronic postobstructive pneumonia

· Lung abscess

· Bronchopleural fistula

· Decreased lung perfusion

Chronic complications may be due to the presence of a foreign body or attempts to remove it. The complication is directly proportional to the delay in extraction time. Pulmonary edema may develop as a collapsed lung re-expands. Bleeding from granulation tissue can be from mild to moderate. Relief of long-standing bronchial obstruction can cause purulent secretions.

ReferencesMichael R Bye. Pediatric Airway Foreign Body. eMedicine

http://emedicine.medscape.com/article/1001253-overview

Updated: May 21, 2009. Retrieved March 4, 2011.

QUESTION1 of 60

  Questions  

  Notes

An 18 year-old college freshman notices difficulty in removing and replacing his shoes at the end of the day and his face appears to be "puffy" and swollen. Over the ensuing two weeks he develops noticeable swelling of his legs all the way up to his thighs. Other than tonsillectomy at age 3, he has never had any medical problems and takes no medications.

On physical examination at the health center, his blood pressure is 118/72, pulse 76, respiration 12, and he is afebrile. Weight is 80 kilograms, an increase of 7 kilograms over his usual weight . He appears well, with no evidence of acute illness. The only finding on physical exam is a 3+ to 4+ pitting edema extending all the way up his legs into the presacral area.

Laboratory evaluation reveals:

CBC normal sodium 140 mmol/L, potassium 3.7 mmol/L, chloride 101 mmol/L, CO2 29 mEq/L BUN 17 mg/dL (6 mmol/L) [normal 8-25 mg/dL or 2.5-9 mmol/L] creatinine 1 g/dL (88.4 μmol/L) [normal 0.6-1.5 mg/dL or 53-132.6 μmol/L] urinalysis: pH 5, specific gravity 1.012, 4+ protein with no blood or glucose urine microscopy: occasional oval fat bodies and rare hyaline casts

Additional labs:

serum albumin 1.1 g/dL (11 g/L) [normal 3-5 g/dL or 35-50 g/L] calcium 7.9 mg/dL (2 mmol/L) [normal 8.5-10.3 mg/dL or 2.1-2.6 mmol/L] phosphorus 3.3 mg/dL (1.07 mmol/L) [normal 3-4.5 mg/dL or 0.97-1.45 mmol/L] total cholesterol 393 (10.16 mmol/L) [normal < 200 mg/dL or < 5.2 mmol/L] 24-hour urine: protein 13.2 g, creatinine 2.248 g Complement levels: normal Serology: ANA, HBV, HCV negative

 What is your preliminary diagnosis?

 

Nephritic syndrome

Nephrotic syndrome

Acute kidney injury

A and C

B and C

 

Explanation

The correct answer is Choice B.

This young man has nephrotic syndrome, which is characterised by:

heavy proteinuria (> 3.5 g / 1.73m2 / day)

hypoalbuminemia due to urinary protein losses

edema due to salt and water retention and reduced oncotic pressure

hyperlipidemia

lipiduria

There are a number of pointers to his not having nephritic syndrome:

his urinary protein losses are too high

he does not have acute kidney injury

he does not have hematuria

he has severe hyperlipidemia which is not a component of nephritic syndrome 

Nephrotic syndrome results from glomerular damage which leads to an  increase in glomerular permeability . This causes proteins and other large substances that would normally not be filtered to pass into the urine. Although albumin is easily measured and most talked about, you should not forget that other proteins including immunoglobulin and complement proteins are often being lost as well.

Nephrotic syndrome results from primary or secondary glomerular damage, primary causes being diagnoses of exclusion when no secondary casue can be found. Pathologically the glomerular manifestations include:

focal segmental glomerulosclerosis (FSGS) in up to 35% of cases

membranous nephropathy in up to 33% of cases

minimal change disease in up to 15% of cases

membranoproliferative glomerulonephritis in up to 14% of cases 

Secondary causes include:

Diabetes mellitus

Infections such as hepatitis B & C, HIV, mycoplasma

Sjogren's syndrome

SLE

Sarcoid

Malignancy including lymphoma and myeloma

Obesity

Drugs such as gold/penicilliamine/NSAIDs/antibiotics/tamoxifen

Patients should be referred to a nephrologist for investigation and likely renal biopsy. While this is pending, management often involves salt and fluid restriction, diuretics for edema, statins for hyperlipidemia, and angiotensin ceonverting enzyme inhibitors in an attempt to reduce protein spillage.

Nephrotic syndrome patients are at risk of DVT (1.5%) or renal vein thrombosis (0.5%), as well as infection (loss of immunoglobulins and complement).

Suggested ReferencesHull RP, Goldsmith DJ. Nephrotic syndrome in adults. BMJ 2008; 336: 1185-1189.

You are looking after a 50 year old man who has severe acute pancreatitis secondary to biliary tract stones. He develops chills and rigors, and spikes a fever of 39.5 Celsius. He is complaining of increasing abdominal pain.

On exam he is jaundiced, and his blood pressure is 100/70 mmHg when supine falling to 90/60 mmHg when sitting, with an increase in heart rate from 95 to 120 beats per minute. His jugular venous pressure appears to be low. His abdomen is distended and clinically consistent with ascites. Over the next few hours his urine output falls from 50 ml/h to 15 ml/h.

Which of the following statements is FALSE?

 

This man is at high risk of acute kidney injury due to obstructive jaundice and hypovolemia

Urine sodium of 10 mmol/L would be consistent with ischemic ATN

He should receive boluses of isotonic saline or colloid until the JVP and BP are normalized, with frequent review of the physical findings

At this time administration of furosemide to increase urine flow is contraindicated

Renal function should be monitored at least daily using serum creatinine

 

Explanation

The correct answer is Choice B.

The classical teaching is that a urinary sodium of < 20 mmol/L is supportive of a diagnosis of hypovolemia or pre-renal oliguria, whereas ATN is classically associated with a urinary sodium of > 40 mmol/L. The logic behind this is that in hypovolemia, the physiological response in defense of intravascular volume is the retention of sodium and water, a process encouraged by activation of the renin-angiotensin-aldosterone system.  In ATN, tubular damage means that sodium reabsorption is incomplete, and sodium spills out into the urine. There are some problems with this approach however.

bilateral renal artery stenosis (whole kidney ischemia) or severe glomerulonephritis (glomerular ischemia) can lead to an artificially low renal sodium even in normovolemia i.e. the kidneys behave as if they are pre-renally impaired

diuretics can lead to inappropriately high urinary sodium despite volume depletion

many patients have intermediate urinary sodium levels (20-40 mmol/L)

One way around the limitations of urinary sodium is to calculate the fractional excretion of sodium (FENa). This is the quantity of sodium excreted divided by the quantity filtered, and expressed as a percentage. The equation for this calculation is (UNa x PCr) / (PNa x UCr) with the result multiplied by 100 to give the FENa as percentage. In hypovolemia, sodium reabsorption is appropriately enhanced and the FENa is < 1%. When tubular injury occurs (ATN)  the FENa rises to > 2%.

Obstructive jaundice and hypovolemia do indeed place this man at high risk of acute kidney injury. In severe pancreatitis there is extensive third space fluid loss, and patients often require large volumes of intravenous fluid replacement to maintain their cardiac preload. These should be administered to clinical euvolemia, at least initially, using end-points such as BP (including postural change), heart rate, and urine output. Central venous pressure measurement can be useful in some patients, but it is the trend in the CVP and the response to fluid that is important, not just the number. The controversy over whether crystalloids or colloids should be used is still ongoing. 

Proponents of colloids point to the inevitable redistribution of crystalloid to the extravascular space after a very short time, leading to very significant edema both visible in the peripheries and flanks, and invisible in internal organs. Crystalloid proponents point to the lack of studies demonstrating better outcome, and to the additional expense of colloid. Regardless of the fluid used, clinical endpoints must be decided upon, targeted, and frequently reassessed, as should renal function (creatinine).

The administration of furosemide to a hypovolemic oliguric patient, simply to increase their urine output, is without physiological basis or clinical justification. There are a number of events during acute pancreatitis that contribute to renal impairment, and none is corrected by furosemide.

hypovolemia due to third space fluid loss

peripheral vasodilatation due to the systemic inflammatory response syndrome (SIRS) - this is the reason for the early rise in CRP and WBC in pancreatitis, not necessarily infection (although this should of course be excluded)

increased intra-abdominal pressure - it is critical that this not be forgotten. Intra-abdominal hypertension or the more advanced intra-abdominal compartment syndrome result in renal venous congestion, potential ureteric obstruction, and a reduction in renal perfusion pressure. If this is not relieved (through drainage of free intra-abdominal fluid or decompressive laparotomy) multiple organ failure will follow as gut and renal perfusion continue to fall. Intra-abdominal pressure can be measured using a pressure transducer attached to the sampling port on the urinary catheter, which is then occluded after 25 ml of normal saline is injected in to the bladder.

 Table 1: Dose modification for patients with renal insufficiency

Table 2: Special considerations for drug use by patients with renal insufficiency

A 26 year old male has an impacted wisdom tooth which is extracted. Several weeks later, he develops a fever, followed several days later by a headache. A head CT scan reveals a 3.5 cm ring-enhancing lesion in the right parietal region; in addition, upon auscultation the patient demonstrates a crescendo/decrescendo heart murmur and a slight thrill in the second intercostal space of the right sternal border. A blood culture grows gram positive catalase and coagulase rich culture. 

Which of the following physical examination findings points to the lesion that increased his risk for these complications?

 

Right carotid bruit

Mitral stenosis

Mitral regurgitation

Mitral valve prolapse

Systolic ejection murmur

 

Explanation

The correct answer is choice E

Systolic ejection murmur (Choice E) is the correct answer. To properly answer this question two things must be identified. Based on the patient's history of having a tooth extracted and having blood cultures positive for Staphylococcus aureus, it should have warranted two main murmurs left in the differential diagnosis; mitral valve prolapse or aortic stenosis. Due to the fact, the murmur is heard best on the right side of the sternal border (not on the left side, like all other murmurs), presentation of a crescendo/decrescendo pitch, and a slight thrill; all clues point towards aortic stenotic findings.

In addition, congenital aortic stenosis causes angina and syncope in many patients. An ejection click can be heard in the neck region displaying a carotid bruit. As with mitral valve prolapse, endocarditis prophylaxis has to be given before any dental procedure to avoid brain abscesses or the former. A phenomenon called pulsus parvus et tardus is another physical characteristic often associated with aortic stenosis. It is a variation in pulse strength and rhythm in the arms and legs, when compared to heart sounds during auscultation.

Right carotid bruit (Choice A) is not the right answer due to the fact it is not the lesion that caused the risk, it is just a symptom of the lesion. Bruits are increased arterial sounds, associated turbulent blood flow.  

Mitral stenosis (Choice B) is not the correct answer because the question does not mention rheumatic fever, enlarged atrium, a snapping sound, or a low pitched-diastolic rumble.

Mitral regurgitation murmurs (Choice C) are normally the correct answer when the patient presents with a left sternal border sound increase, which decreases as it radiates to the left axilla creating a blowing murmur. 

Mitral valve prolapse (Choice D), which is associated with mitral regurgitation is not the correct answer. If the patient has a delayed systolic murmur on left side of the sternal border, a tumor in the heart chamber, or a "mid-systolic click," this answer would be correct.

You are working in a local TB health center and you are about to interpret the result of a Mantoux tuberculin skin test on one of your patients who has had a history of fever and cough.

Which of the following is NOT true about tuberculin skin testing (TST) for tuberculosis?

 

Patients who have received BCG vaccine should not have TST.

An initially negative test does not exclude the possibility of active infection.

A subsequent (2nd) negative test, several weeks after the first, does not exclude the possibility of active infection.

A previously TST-positive patient can become TST-negative later in life.

For TST to reflect recent infection it should be done > 3 weeks after exposure

 

Explanation

The correct answer is Choice A.

The topic of tuberculin skin testing is a frequent cause of confusion. It is critical to understand the basic principles behind the test, and you will then be able to work out the answers to questions on this topic, rather than relying on having seen them before and perhaps missing a change in wording.

The tuberculin skin test relies on the generation of a cell mediated immune response to the injected purified protein derivative (PPD). This positive response requires two conditions to be met:

1. prior immune exposure to Mycobacteria

2. immune "memory" of this exposure so that rechallenge induces a response

These two simple facts are the key to understanding the potential for false negative and false positive results, and also for understanding the need for, and response to, repeat testing.

Let's get choice D out of the way first. Cell-mediated immunity can wane over time when a subject is not re-exposed to the stimulus. So it is possible for someone to have a true positive TST now, but if re-tested in 12 years time to have a negative one due to this waning. It has been argued that you should not retest someone who has had a positive TST. Once you have had a true positive test it will effectively rule out its diagnostic usefulness in the future because it may not wane and will be positive subsequently despite no further exposure or infection. If the test wanes and is then repeated a few week later in the other arm it may be positive again since the first test will have reminded the immune system about the original exposure. It still isn't diagnostic of anything. So if the test is positive you need to evaluate the patient for active TB and consider treatment for latent TB, based on their exposure history and for example their risk of reactivation of old TB.

The development of the cell-mediated immune response that is necessary for a positive TST requires time, and 3 weeks has been suggested as adequate. This means that a test done < 3 weeks after exposure may be negative despite latent TB. It also means that a single negative test does not rule out infection, if exposure has been recent. It is easy to see that TST must be carried out after a clear history of exposure has been taken. It is possible to have 2 negative TST, the second several weeks after the first, if exposure has been too close to the time of the second test for cell-mediated immunity to have responded.

The issue of BCG and TST is an interesting one. The key here is to establish the age at which BCG vaccination took place and the time from the vaccination to the present. Patients vaccinated at age < 1 year usually demonstrate waning of immunity such that the BCG vaccine has no effect on TST after 10 years, and a positive result can be interpreted as such. Children vaccinated at age 5-6 may well have a very prolonged TST positivity, 20% being still positive after > 10 years. In the setting of a positive TST 8 years after BCG for example, an interferon gamma release assay will distinguish between a positive response due to vaccination and a

positive response due to latent TB infection.

Going back to our two necessary criteria, you will note that we stated prior exposure to Mycobacteria, and not prior exposure to TB. This is because false positive tests may occur from exposure to other non-tuberculous Mycobacteria. The relative frequency of this depends on the prevalence of infection with these agents in the population. In the USA 1-4% of positive TST are false positives due to exposure to non-tuberculous Mycobacteria.

Our criteria also let us see that false negative tests can occur in settings where cell-mediated immunity is insufficient by virtue of immunosuppressive drugs or diseases, or has waned naturally over time as discussed above.

An HIV positive male with a history of IV drug abuse and schizophrenia is brought to the emergency department in a confused, incoherent and agitated state. Vitals are pulse 118, BP 160/90, respiratory rate 15, and temperature is 37.5 celcius orally. His skin is hot and flushed and you noticed he has dilated pupils. The physical examination is otherwise unremarkable. Medical records indicate that his regular medications include chlorpromazine, cogentin, and acyclovir.The most likely diagnosis is which of the following conditions:

Opiod toxicity

Anticholinergic intoxication

Barbiturates toxidrome

Cocaine toxicity

Cholinergic toxidrome

ExplanationThe correct answer is choice B.

This patient exhibits evidence of the anticholinergic toxidrome. This syndrome is best described as "hot as a hare, dry as a bone, and mad as a hatter." It also produced pupil dilation, urinary retention (an important differentiating factor compared with sympathomimetic syndromes), and seizures.

He is currently taking two medications (chlorpromazine and cogentin) that produce anticholinergic symptoms.

  Table 1: Review of Common Toxidromes

The tuberculin test can identify patients with latent TB. False negative tuberculin tests occur when patients do not react to the injected tuberculin purified protein derivative (PPD), even though they are infected with M. tuberculosis. According to the CDC, false-negative reactions can occur in the following settings (this list is not exhaustive):

Cutaneous anergy - inability to react to skin tests due to immunosuppression

Recent TB infection (within 8-10 weeks of exposure) - the test relies on the development of cell-mediated immunity (CMI)

Very old TB infection (many years)

Patients less than 6 months old and the elderly, through decreased CMI

Recent immunization with a live-virus vaccine (e.g. smallpox, measles, mumps, polio)

Overwhelming TB disease e.g. miliary

Viral infections (e.g. measles and chicken pox)

Metabolic disease including malnutrition and CKD (again, impaired CMI)

Incorrect test administration

Incorrect reading of the test

These tests must be performed and interpreted in a standardized way.

Inject 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm

Use a tuberculin syringe and the bevel of the needle should be facing upwards

Make an intradermal injection - this should produce a pale wheal 6 to 10 mm in diameter

The skin test reaction should be read 48-72 hours after injection

You will be measuring the size of the area of induration (palpable, raised, hardened area or swelling) NOT erythema, and it is the diameter in mm ACROSS the forearm, not along it.

The interpretation of the test result depends not just on the size of the induration but also on the risk of infection and progression of disease:

The new guidelines recommended that only patients with the highest risk of endocarditis and adverse outcomes from endocarditis receive antibiotic prophylaxis.  These groups include patients with:

Unrepaired cyanotic heart disease Repaired heart disease (cyanotic or acyanotic) with prosthetic material, within 6 months of the procedure Repaired heart disease (cyanotic or acyanotic) with residual defects at the site of a prosthetic patch (which inhibit

endotheliazation) Prosthetic valves Previous infective endocarditis Cardiac transplantation patients with valvulopathy

QUESTION9 of 60

  Questions  

  Notes

A six year old girl comes to your office for her annual check up. On physical examination, you note a normal S1 and S2 as well as a soft systolic murmur with a vibratory character, heard best over the right upper sternal border.  You suspect an innocent murmur, but her mother asks if she should be referred to a cardiologist. 

Each of the following findings would support the diagnosis of a pathological murmur EXCEPT:

 

the murmur occurs in diastole

the murmur is associated with a thrill

the murmur is louder in the supine position and softer when the child sits upright

the child has mild finger clubbing

there is a loud P2 component of the second heart sound

 

Explanation

The correct answer is Choice C.

Heart murmurs are common in children - as many as 50% of healthy children will have a murmur detected at some point in childhood.  Most murmurs in childhood are "innocent" and not associated with significant cardiac disease.  The child in the vignette has one such murmur: a Still's murmur, classically described as having a "vibratory" or "musical" component.   

Fundamentally, the presence of a heart murmur only indicates the existence of turbulent blood flow.  Most innocent murmurs are "flow murmurs", caused by increased blood flow through normal cardiac anatomy.  Children with fever or anemia have increased cardiac output/blood flow and thus will have louder flow murmurs.  Physical exam maneuvers, such as listening to the heart in the supine and then sitting positions (choice C), will also increase the intensity of a murmur.  When the child is lying down, blood return to the heart is increased, increasing cardiac preload.  This results in increased cardiac output and a louder murmur.  The opposite situation occurs in adolescents with hypertrophic cardiomyopathy.  In this illness, the left ventricular outflow tract is partially obstructed by hypertrophied myocardium.  When stroke volumes are large, the tract is stented open by the blood flow - but when stroke volume decreases, the obstruction worsens, leading to increased turbulence.  When these patients move from lying down to the sitting or standing position, their murmurs will be much louder. 

All innocent murmurs and flow murmurs are systolic.  Any diastolic murmur (choice A) is pathological and should be evaluated further. 

Louder and harsher murmurs are also more likely to be pathologic.  Any murmur associated with a thrill (grade IV/VI or higher) is likely to be associated with cardiac disease (choice B). 

Symptoms of cardiac disease - such as digital clubbing (choice D) - that occur in the presence of a murmur always merit further evaluation.  Other symptoms of heart disease in infants and children can include failure to thrive, cyanosis, or sweating or easily tiring out during feedings. 

A loud P2 (choice E) indicates pulmonary hypertension, which results from many congenital heart diseases that are associated with increased pulmonary blood flow. A 35 year-old female presents at the ER with anxiety, fatigue, dizziness, nausea and vomiting, reporting a loss of 10 kg during the last year. She is thin, with a BMI of 16. She has notes increased generalized skin pigmentation over the last year and a half.  Counseling that she received for he feelings of anxiety during the last three months has not helped any of her symptoms.  Her supine blood pressure is 94/58 mmHg and standing 81/55 mmHg, so you note slight orthostatic intolerance. Her pulse is 82/min. Her sodium level is 119 mmol/l (normal 135-145), potassium is 5.3 mmol/l (normal 3.5-5.0). Cortisol is extremely low even when challenged with ACTH, and ACTH is very high. On further testing, she tests positive for adrenal cortex antibodies.

Management of this patient should include all of the following except:

 

IV hydrocortisone

thyroid function tests

IV hypertonic sodium chloride

oral fludrocortisone

mineralocorticoid replacement only when steroids weaned

All of the above are true

 

Explanation

The correct answer is choice C

Named for Thomas Addison, the physician who first described the condition in 1855, Addison disease is adrenocortical insufficiency, due to dysfunction or destruction of the adrenal cortex. Since this can occur gradually with symptoms developing only after about 90 percent of both adrenal glands is destroyed, Addison disease tends to present between the ages of 30-50 years. Though it is a common topic on exams, it is a very rare disease, with an incidence today of 40-60 cases per 1 million people. It was more common in the past as a sequela of tuberculosis (TB) which can destroy the adrenal glands, and several famous individuals have had it, most notably US President John F Kennedy. Certain authors such as Charles Dickens and Jane Austen have been speculated to have had Addison disease as well.

When not the result of TB, Addison disease is thought to develop due to atrophy, lymphocytic infiltration, and fibrosis of the adrenal cortex, resulting from autoantibodies, generally with no destruction of the adrenal medulla, and patients may be predisposed due to hereditary factors. Due to a lack of cortisol, patients may exhibit nausea, vomiting, and fatigue as in the case of this patient. Females may present with amenorrhea and men with impotence and decreased libido. Patients are hypotensive and may demonstrate orthostatic intolerance and complain of dizziness as well. If severe this can lead to presyncope and syncope. Hypoglycemia is to be expected due to lack of cortisol. In diabetic patients, patients also may become hypoglycemic due to increased sensitivity to insulin.

Reduced cortisol leads to an increase in pituitary secretion of ACTH, which stimulates melanocytes in the skin to produce melanin. Generally, this effect precedes the other symptoms, since for a time the increased ACTH can help to squeeze a little more cortisol out of the deteriorating adrenal glands. Eventually, however, weakness, fatigue, reduced appetite, and weight loss develop progressively. Hyperkalemia results from the lack of cortical hormones and this leads to myalgias and flaccid muscle paralysis.

Since blood pressure, volume, and electrolyte balance needs to be restored, IV infusion of isotonic sodium (thus choice C is incorrect) is necessary immediately, while IV hydrocortisone (choice A) will provide the patient with an immediate burst of the deficient hormone that is causing her condition. Subsequently, you will need to get her started on oral fludrocortisone (choice D). A variety of other autoimmune conditions may occur in association with Addison disease and these include the autoimmune thyroid conditions Hashimoto thyroiditis and Graves disease. For this reason, it is important to carry out thyroid function tests (choice B).

As long as the patient is receiving 100 mg or more of hydrocortisone in 24 hours, no mineralocorticoid (choice E) replacement is necessary. The mineralocorticoid activity of hydrocortisone in this dosage is sufficient.An agitated and combative 23 year old female is brought to the emergency department by her concerned roommate.  Laboratory evaluation shows:

Sodium 143 mEq/L Potassium 4.3 mEq/L Chloride 101 mEq/L Bicarbonate 9 mEq/L

Blood urea nitrogen 18 mg/dL Creatinine 0.8 mg/dL Glucose 74 mg/dL

An arterial blood gas shows pH 7.33, pCO2 26 mm Hg, pAO2 103 mm Hg, and a base excess of -15. 

Which of the following is the most appropriate interpretation of this patient's acid-base disorder?

 

Acute respiratory acidosis without evidence of compensation

Acute metabolic acidosis without evidence of compensation

Acute respiratory acidosis with simultaneous acute metabolic acidosis

Acute metabolic acidosis with partial respiratory compensation

Acute respiratory acidosis with partial metabolic compensation

 

Explanation

The correct answer is choice D. 

Even if you think you don't understand acid-base disorders or acid-base physiology, most questions can be easily answered by recalling the bicarbonate buffer equation:

CO2 + H2O< --> H2CO3< --> H+ + HCO3

Bicarbonate is the body's major buffer system.  A low serum bicarbonate means that this patient has a metabolic acidosis, regardless of what other abnormalities may be present.  Look at the equation above: if you remove bicarbonate, the equation shifts to the right, generating more protons and thus more acidosis.

The low pCO2 indicates that the patient has increased his or her minute ventilation in an effort to "blow off" CO2 and create a respiratory alkalosis.  This would be an appropriate compensatory mechanism in the face of a primary metabolic acidosis.  Again, look at the equation above: if you remove CO2, the equation shifts to the left, removing protons (H+) and generating alkalosis.

This patient, however, has compensated only partially.  A good rule of thumb is that, in a patient with metabolic acidosis, the pCO2 should drop by an amount that equals 1.2 times the drop in the serum bicarbonate.  Here, the serum bicarbonate dropped by about 15 (from a normal bicarbonate of about 24 to 9).  Multiply this by 1.2 and you get 18.  Thus, if the patient had been able to lower her pCO2 to about 22 or so (40 - 18), then the pH of the blood would have returned to normal. 

In a patient with an acute respiratory acidosis without evidence of compensation (choice A), the pCO2 would be high, and the serum bicarbonate normal. 

In a patient with an acute metabolic acidosis without evidence of compensation (choice B), the serum bicarbonate would be low, and the pCO2 normal.

In a combined respiratory and metabolic acidosis (choice C), the pCO2 would be elevated, while the bicarbonate would be low. 

Acute respiratory acidosis (choice E) with partial metabolic compensation would result in an elevated pCO2 with an elevated serum bicarbonate. 

Suggested ReferencesHerd AM. An approach to complex acid-base problems: keeping it simple. Can Fam Physician. 2005; 51: 226-232.

QUESTION12 of 60

  Questions  

  Notes

A 7 year old male is brought to the emergency department by his grandmother for evaluation of altered mental status.  You assess the patient, noting a somnolent child who moans in response to noxious stimuli. Vital signs include temperature 37.1 C, pulse 132 bpm, respirations 20/min, blood pressure 174/100, and oxygen saturation 94% in room air.  As you begin the physical examination, the patient experiences a generalized, tonic-clonic seizure. Seizure activity stops following a dose of intravenous lorazepam.   

Which of the following is the most appropriate next step in the management of this patient?

 

Computed tomography (CT) of the head without intravenous contrast

Lumbar puncture

Sublingual nifedipine

Intravenous fosphenytoin

Intravenous nitroprusside

 

Explanation

The correct answer is choice E.  

This patient has a hypertensive emergency, defined as severe hypertension associated with evidence of end-organ damage. Treatment with an intravenous antihypertensive agent like nitroprusside (choice E), hydralazine, labetalol, or nicardipine should be

initiated immediately, with the goal of lowering the blood pressure by no more than 25% over the first several hours.  

A CT scan of the head without i.v. contrast (choice A) is a rapid and useful test for identifying acute intracranial bleeding.  It would be useful to obtain this test as quickly as possible in a patient like the one described - but not before he is stabilized!  Sending a patient with unstable vital signs to radiology would be a very dangerous decision - you should treat this patient's severe hypertension first.  

A lumbar puncture (choice B) could be useful in evaluating new-onset seizures, as it would identify infections like meningitis or encephalitis.  However, this patient has a more likely reason to seize - his blood pressure.  Moreover, performing an LP without first ruling out increased intracranial pressure puts the patient at risk for cerebral herniation and death.  

Sublingual nifedipine (choice C) was commonly used in the treatment of hypertensive urgencies and emergencies before evidence emerged that, at least in adults, this treatment could be harmful.  In 1996, the U.S. FDA recommended not using nifedipine for this purpose.  The problems seem to occur because the initial drop in blood pressure can be too great, causing decreased perfusion to the heart or brain.  Treatment with rapidly acting intravenous agents is now preferred, as these can be more easily titrated minute-by-minute to prevent excessive drops in BP.  

Fosphenytoin (choice D) would be the agent of choice for status epilepticus that does not respond to first-line therapy with benzodiazepines.  However, this patient's seizures (for the moment, at least) have stopped.  Giving additional anticonvulsants will not be as helpful as treating the cause of this patient's seizure.

A test’s sensitivity is the proportion of patients who have the disease being evaluated who also have positive test results. This can be calculated by dividing the number of patients with “True Positive” test results by the total number of patients who actually have the disease for which they are being tested (see Figure 1 below).

In our study, 95 of the people with PEs had positive test results. Another 5 subjects had negative test results even though they actually had PEs, so the total number of patients in our sample who had PEs is 5 + 95. The new test’s sensitivity is therefore 95/(5 + 95).

The Alveolar-arterial (A-a) gradient is calculated by the formula:

PA02-Pa02

Where PA02 = Fi02 x (pAtm -pH20) - PaCo2/RQ

Fi02 is the fraction of inspired oxgyen, 21% for a patient breathing room air.

pAtm is atmospheric or barometric pressure, usually assumed to be 760 mm Hg or Torr, the average pressure at sea level.

pH20 is water vapor pressure, 47 mm Hg at 37oC.

RQ is the respiratory quotient or the ratio of carbon dioxide produced to oxygen consumed by the body under steady-state conditions. It varies between 0.7 to 1 with an average of 0.8.

Using this formula and the values specified the patient has an A-a gradient of 66, therefore answer D is correct.

The A-a gradient is a measure of the efficiency of blood oxygenation. It is altered by ventilation/perfusion defects or diffusion problems but not by hyper- or hypoventilation. Normal values vary with age but generally are between 7 - 14 for a patient breathing room air.

The CT scan image shows a large, bulky, somewhat lobulated, heterogeneously enhancing mass of the left anterior mediastinum. There is also evidence of bilateral hilar and subcarinal lymphadenopathy.

Malignant schwannoma (choice E) is the only mediastinal tumor listed above that characteristically occurs in the posterior mediastinum, and not the anterior mediastinum.

The remainder of the choices, malignant thymoma (choice A), lymphoma (choice B), metastatic disease (choice C), and thyroid carcinoma (choice D) can all occur in the anterior mediastinum and should be listed in the differential diagnosis of this compartment, particularly in the presence of mediastinal lymphadenopathy.

Differential diagnoses for anterior, middle, and posterior mediastinal lesions are well established. Some of the conditions overlap and may be found in more than one of the mediastinal compartments. A summary of those differential diagnoses is as follows”

Anterior mediastinal lesions – “the 4 T’s” – Thymoma, Teratoma, Thyroid tumor/goiter, Terrible lymphoma. Thymoma is the most common tumor of the anterior mediastinum and anywhere from 30-50% of patients with thymoma have associated myasesthenia gravis. Parathyroid tumors may also be present in the anterior mediastinum. Lymphadenopathy of the anterior mediastinum may also be present due to metastatic disease as well as lymphoma. Morgagni hernia is also included in this category as well as aneurysm of the ascending aorta.

Middle mediastinal lesions – include causes of lymphadenopathy: lymphoma, metastatic disease, tuberculosis, coccidioidomycosis, sarcoidosis, and silicosis. Bronchogenic carcinoma and primary tracheal neoplasms may cause middle mediatstinal mass lesions. Other potential middle mediastinal lesions include foregut duplication abnormalities such as brochogenic cyst and extralobar sequestration. Aneurysms of the aortic arch or its major branches are also included in this category.

Posterior mediastinal lesions – Neruogenic tumors make up the largest group of posterior mediastinal tumors (neuroblastoma, ganglioneuromas, schwannoma, neurofibroma). Tumors of the spine may present as a posterior mediastinal mass – aneurysmal bone cyst, chondrosarcoma, osteosarcoma, Ewing’s sarcoma, myeloma and metastasis. Other spine-related conditions to consider are neurenteric cysts, lateral meningoceles, and estramedullary hematopoiesis. A paraspinous abscess may also present in the posterior mediastinum. Lympadenopathy due to lymphoma or Castleman’s disease may also present here. Aneurysms of the descending aorta and GI abnormalities such as hiatal hernia and esophageal tumors (cancer and leiomyoma) are included here as well. Foregut duplication abnormalities such as brochogenic cyst and extralobar sequestration can occur in the posterior as well as the middle mediastinum compartments. 

Itraconazole is the correct answer because it is one of the accepted treatments for blastomycosis. Oral itraconazole 200–400 mg/day for at least 6 months for non-immunocompromised patients with indolent forms of the disease. The lower dose is often sufficient. Continue for at least 3 months after the lesions have resolved. 

Blastomycosis is a relatively rare granulomatous disease caused by the dimorphic fungus Blastomycetes dermatitidis, with a clinical manifestation spectrum including acute pulmonary disease, subacute and chronic pulmonary disease, and disseminated extrapulmonary disease. The skin (chronic non-healing ulcer's) is the most common site for dissemination, followed by bone, genitourinary tract, and central nervous system. The respiratory manifestations of most blastomycosis sufferers are nonspecific and include a non-productive cough. Some, however, can have impressive CXR findings.

Hypersensitivity pneumonitis represents a respiratory illness resulting from exposure to inhaled allergens to which a patient has been previously sensitized. It presents with flu-like symptoms, cough, and shortness of breath that are temporally related to allergen exposure. There is classically a restrictive defect on PFTs with reduced carbon monoxide transfer.The time between heavy exposure and symptoms is often 4-8 hours, consistent with the time scale of T-cell activation, so symptoms often occur after occupation exposure is over. Patients may be symptom free on days when exposure is limited or absent. There is significant inflammation within the lungs, contributing to radiographic infiltrates and weight loss.

The list of potential triggers is very large. Classically the illness results from exposure to mouldy hay or farm dust (Farmer's lung), or bird feathers and excrement (Pigeon-fancier's lung). However, many industrial substances and dusts have been implicated, as well as micro-organisms present within the materials being worked with. Thus we have woodworker's lung, sauna taker's lung, animal handler's lung etc. The patient here will have been exposed to animal dander and excrement repeatedly, and the inhalational load will have been substantial during brushing and shovelling activities. The time-scale from exposure to symptoms is classical, as is the absence of symptoms on certain days.

Hypersensitivity pneumonitis occurs more frequently in non-smokers. The acute form demonstrated by this patient is associated with immune complex deposition in the lungs. Resolution of the acute form can take days after exposure ceases, and careful history taking may be required to identify the precipitant, taking into account the time delay in symptoms.

Diagnosis is not usually difficult provided a clear history is obtained, searching for exposure, periodicity, and symptom free periods. Without the history the clinical features can be consistent with other interstitial lung diseases. Diagnosis relies on the presence of a number of features:

This infant has persistent pulmonary hypertension of the newborn (PPHN).  Remember that in fetal life, oxygenation occurs in the

placenta - the resistance in the pulmonary vascular bed is high, and blood is shunted away from the fetal lungs through the ductus arteriosus and the foramen ovale.  At birth, however, the pulmonary vascular resistance should drop, beginning with the infant's first breath.  This allows blood to enter the lungs to be oxygenated, and the foramen ovale and ductus arteriosus should close within hours to days of birth. 

In some infants, this process does not occur - the vascular resistance in the pulmonary bed remains high.  Because blood follows the path of least resistance, it is thus "easier" for the blood to pass through the ductus arteriosus or foramen ovale and enter the systemic circulation, without ever passing through the lungs to be oxygenated.  This causes hypoxemia and cyanosis. 

PPHN can result from a variety of conditions, most notably meconium aspiration syndrome and congenital diaphragmatic hernia.  Infants of diabetic mothers also have an increased rate of PPHN - and this infant's large size suggests that may be the case in this vignette. 

Even if you didn't recognize that this was PPHN, the clues in the stem should have led you to that physiologic explanation.  For example, the chest x-ray shows decreased pulmonary vascular markings, indicating that blood is not ever entering the lungs.  Also, the single, loud S2 is a marker of pulmonary hypertension.

Methemoglobinemia (choice A) can cause cyanosis, but the pAO2 should improve markedly with the administration of 100% oxygen.  Classically, patients with methemoglobinemia will remain cyanotic even on 100% O2, even though their pAO2 is high. 

Hypoventilation (choice B) can cause hypoxemia and cyanosis, but would also cause CO2 retention. 

Complex congenital heart disease (choice D) could cause cyanosis.  However, the improvement that this patient experienced with 100% oxygen suggests that this is not the case.  Even with 100% oxygen, infants with cyanotic heart disease will seldom attain a pO2 of greater than 100 mm Hg, or have a rise of greater than 10-30 mm Hg from their pre-hyperoxygenated baseline.  Also, in this case, there are clues in the chest x-ray and physical exam that suggest an alternate mechanism of hypoxemia.

Acrocyanosis (choice E) is a bluish discoloration of the extremities that is a normal finding in infants.  It is not associated with systemic hypoxemia.  This infant's cyanosis is initially severe and pronounced, and associated with a markedly decreased pAO2. 

A 15-year-old high school student and several of her friends ate lunch at a local Chinese restaurant. They all were served the daily luncheon special, which consisted of sweet and sour pork with vegetables and fried rice. All the girls developed nausea, vomiting, abdominal pain, and diarrhea within 6 hours of eating lunch. They were all sent to the local emergency department for work-up of their suspected food poisoning. The children are all otherwise healthy and none are on any medication and have no known allergies.

Which of the following is the most likely cause of these symptoms?

 

Bacillus cereus

Staphylococcus aureus

Clostridium botulinum

Clostridium perfringens

EHEC (Enterohemorrhagic Escherichia coli)

 

Explanation

The correct answer is Choice A.

The most likely cause of the patient's symptoms is infection by Bacillus cereus, (Choice A) a Gram-positive rod that causes foodborne illness.  Improperly cooked food allows bacterial endospores to survive while subsequent improper refrigeration allows for germination of the bacterial endospores and production of enterotoxins. 

Bacillus cereus causes two separate forms of illness: an emetic form and a diarrheal form. Improperly cooked and stored rice is one of the most commonly implicated foods associated with the emetic form.  The emetic form is caused by a toxin named cereulide, which leads to nausea and vomiting a short time (2 to 6 hours) after ingestion.  The diarrheal form is caused by three toxins: Hemolysin BL, Nonhemolytic Enterotoxin, and Cytotoxin K.  Many different types of food are associated with the diarrheal form and symptoms of watery non-bloody diarrhea and abdominal cramps occur 8 to 20 hours after ingestion.

Staphylococcus aureus (Choice B) is a Gram-Positive cocci which is found in clusters. Staphylococcus aureus  is coagulase positive and causes a variety of infections including impetigo, cellulitis, osteomyelitis, endocarditis, and myositis.  Staphylococcus aureus food poisoning occurs due to the ingestion of preformed toxins (heat and acid-stable staphylococcal enterotoxins).  Illness can occur as soon as 4 hours after eating contaminated food.  Staphylococcal enterotoxins act directly on neural receptors in the upper gastrointestinal tract which leads to stimulation of the vomiting center of the brain.  Typical foods associated with Staphylococcus aureus food poisoning include ham, cream filled pastries, and potato salad.

Clostridium botulinum (Choice C) is a Gram-Positive anaerobic spore forming rod which causes botulism.  Botulism is caused by the ingestion of a pre-formed neurotoxin.  Botulism toxin prevents the release of the neurotransmitter acetylcholine, which interferes with neurotransmission at peripheral cholinergic synapses.  Clinical disease occurs within 12 to 36 hours after ingestion and is characterized by a flaccid paralysis.  The

cranial nerves are affected first, particularly those involving the eyes causing diplopia and blurred vision.  Difficulty swallowing is another early sign.  The paralysis descends with subsequent involvement of respiratory muscles.  The toxin does not produce systemic signs of fever or sepsis and patients typically succumb to paralysis and respiratory failure.

Clostridium perfrigens (Choice D) is a Gram-Positive anaerobic spore forming rod.  Clostridium perfrigens  food poisoning often occurs when poultry, meat, or fish is precooked and then reheated before serving.  Spores of Clostridium perfrigens resist the first heating and then germinate in the food.  Upon ingestion, the organisms sporulate in the intestine and form a heat-labile enterotoxin which inhibits glucose transport, damages the intestinal epithelium, and causes protein loss into the intestinal lumen.  Clostridium perfrigens  food poisoning is characterized by watery diarrhea, severe cramping, and abdominal pain which begins 8 to 24 hours after the suspected meal.  The illness typically lasts 24 hours or less.

Enterohemorrhagic Escherichia coli (Choice E) is a Gram-Negative rod.  EHEC occurs by ingestion of contaminated beef which produces SLT I and II (Shiga-like toxin (verotoxin)).  The toxin causes rearrangement of actin, damage to microvilli, and systemic toxemia, however, it is not invasive.  The diarrhea is copious, watery, and bloody with minimal neutrophils.  This diarrhea is associated with serious complications, including hemorrhagic colitis, hemolytic uremic syndrome (HUS), and thrombotic thrombocytopenic purpura (TTP).  The particular serogroup associated with Enterohemorrhagic Escherichia coli  is O157:H7.The following, often transient, changes may be seen in a large pulmonary embolus.

-an S1Q3T3 pattern-a prominent S wave in lead I-a Q wave and inverted T wave in lead III-sinus tachycardia-T wave inversion in leads V1 - V3-Right Bundle Branch Block-low amplitude deflections

Tripe palms are characterised by thickened velvety palms that have the appearance of tripe, the stomach lining of beef, pork, or sheep. Approximately 90% of cases of tripe palms are associated with internal malignancy. This skin disease is very rare. It usually occurs before the diagnosis of the cancer, but may arise during any point in the course of the malignancy.

Tripe palms are frequently seen in conjunction with acanthosis nigricans. In these cases, the underlying malignancy is most commonly stomach (35%) or lung (11%) cancer. In cases where tripe palms occur without acanthosis nigricans, lung cancers are usually responsible. Less commonly associated cancers include head and neck tumours, and tumours of the genitourinary tract.

In over 40% of patients, tripe palms are the first sign of an undiagnosed cancer, hence all patients should undergo a full diagnostic workup for an associated malignancy, particularly lung or gastrointestinal carcinoma.

The geographical clue in this scenario is relevant, because the Mississippi Valley is the area where most cases of blastomycosis are contracted. Amphotericin B is considerably more toxic, and is usually reserved for immunocompromised patients who are critically ill and those with central nervous system disease (Amphotericin B 0.7–1.0 mg/kg/day, to a total dose of 1.5–2.5 g. This may be used in immunocompromised patients or itraconazole failures. Switch to itraconazole after initial amphotericin B response). Fluconazole has also been tested on patients with some favourable results. Fluconazole is useful where itraconazole is not absorbed; 400–800 mg/day for 6–9 months.

Some fungal infections are more common in certain geographic areas and for exam purposes, this is key to remeber. For example,

in the United States, coccidioidomycosis occurs almost exclusively in the Southwest. Histoplasmosis is especially common in the Ohio and Mississippi River valleys. Blastomycosis is particularly common in the midwestern and southeastern United States (and in Central and South America and parts of Africa).

Ciprofloxacin (Choice B) is incorrect because quinolone antibiotics have no utility in the management of fungal infections such as blastomycosis but, rather, have broad spectrum activity that is dependent upon the actual compound. Examples of quinolones and their usual usages would be ciprofloxacin (Cipro) for urinary tract infections; levafloxacin (Levaquin) for pneumonia and urinary tract infections; and moxifloxacin (Avelox) for pneumonia and acute sinusitis.

Doxycycline (Choice C) is incorrect because this antibiotic is used in the treatment of atypical bacterial and other infections, but has no utility in the management of fungal concerns. Doxycycline is used in the management of acne, Legionella, Chlamydial cervicitis, and acute exacerbations of chronic bronchitis, amongst many others.

Linezolid (Choice E) is incorrect because this powerful antibiotic, a member of the oxazolidinone class, is used for the treatment of infections caused by multi-resistant bacteria including Streptococcus and methicillin-resistant Staphylococcus aureus (MRSA).

This patient's elevated A-a gradient is most likely the result of a diffusion defect or ventilation/perfusion mismatch, also called a shunt. That is, the lungs are perfused normally but, due to his apparent pneumonia, the alveoli are filled with fluid and unable to be adequately ventilated.

Kawasaki disease. 

Differential must include SJS/early TEN with the eye/lip involvment, scarlet fever is a good choice and other viral causes including measles (non exudative conjunctivitis).