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BRONCHIAL ASTHAMA
Student: LOGANATHAN ASHOK KUMAR
GROUP 20
3RD YEAR, 2ND SEMESTER.
KURSK STATE MEDICAL UNIVERSITYDEPARTMENT OF PATHOPHYSIOLOGY
Teacher: Alexey A. Kryukov Ph.D.
Associate professor dept.of
Pathophysiology.
contents
BRONCHIAL ASTHMA
• Definition
• Etiology
• Epidemiology
• Classification
• Pathogenesis
• Investigations
• Treatment
Definition
• Asthma attacks all age groups but
often starts in childhood. It is a disease
characterized by recurrent attacks of
breathlessness and wheezing, which
vary in severity and frequency from
person to person. In an individual, they
may occur from hour to hour and day
to day.
• This condition is due to inflammation of
the air passages in the lungs and
affects the sensitivity of the nerve
endings in the airways so they become
easily irritated. In an attack, the lining
of the passages swell causing the
airways to narrow and reducing the
flow of air in and out of the lungs.
Asthma is a common condition that caused
considerable morbidity
In adult -5% (1:1 male/female)
Children -10% (2:1 male/female preponderance)
56,8 cases per 100.000 population in Russia
(2001y.)
BA occurs at all ages, but predominantly in early
life: 1/2 cases before age 10,
1/3 cases before age 40
Etiology
• The strongest risk factors for developing asthma are exposure,
especially in infancy, to indoor allergens (such as domestic mites in
bedding, carpets and stuffed furniture, cats and cockroaches) and a
family history of asthma or allergy. A study in the South Atlantic Island
of Tristan da Cunha, where one in three of the 300 inhabitants has
asthma, found children with asthmatic parents were much more likely
to develop the condition.
• Exposure to tobacco smoke and exposure to chemical irritants in the
workplace are additional risk factors. Other risk factors include certain
drugs (aspirin and other non-steroid anti-inflammatory drugs), low
birth weight and respiratory infection. The weather (cold air), extreme
emotional expression and physical exercise can exacerbate asthma.
• Urbanization appears to be correlated with an increase in asthma.
The nature of the risk is unclear because studies have not taken into
account indoor allergens although these have been identified as
significant risk factors.
Trigger factors
Epidemiology
Between 100 and 150 million people around the globe -- roughly
the equivalent of the population of the Russian Federation --
suffer from asthma and this number is rising. World-wide,
deaths from this condition have reached over 180,000
annually.
• Around 8% of the Swiss population suffers from asthma as
against only 2% some 25-30 years ago.
• In Germany, there are an estimated 4 million asthmatics.
• In Western Europe as a whole, asthma has doubled in ten
years, according to the UCB Institute of Allergy in Belgium.
• In the United States, the number of asthmatics has leapt by
over 60% since the early 1980s and deaths have doubled to
5,000 a year.
• There are about 3 million asthmatics in Japan of whom 7%
have severe and 30% have moderate asthma.
• In Australia, one child in six under the age of 16 is affected.
Asthma is not just a public health problem for developed
countries. In developing countries, however, the
incidence of the disease varies greatly.
• India has an estimated 15-20 million asthmatics.
• In the Western Pacific Region of WHO, the incidence
varies from over 50% among children in the Caroline
Islands to virtually zero in Papua New Guinea.
• In Brazil, Costa Rica, Panama, Peru and Uruguay,
prevalence of asthma symptoms in children varies from
20% to 30%.
• In Kenya, it approaches 20%.
• In India, rough estimates indicate a prevalence of
between 10% and 15% in 5-11 year old children.
Economy
• From 2000–2010, the average cost per asthma-related hospital
stay in the United States for children remained relatively stable
at about $3,600, whereas the average cost per asthma-related
hospital stay for adults increased from $5,200 to $6,600.
• In 2010, Medicaid was the most frequent primary payer among
children and adults aged 18–44 years in the United States;
• private insurance was the second most frequent payer. Among
both children and adults in the lowest income communities in
the United States there is a higher rates of hospital stays for
asthma in 2010 than those in the highest income communities.
Asthma in world wide
Classification• According to etiology:
• BA is a heterogeneous disease.
types of asthma:
Allergic Idiosyncratic
(extrinsic, atopic, (intrinsic, non-
early onset) atopic, late onset)
Drug induced asthma(Aspirin,Tartrazine,Beta-adrenergic antagonists,Sulfiting agents.)
Exercise induced asthma
Initiation of bronchospasm
by exercise (cross –country
skiing, or ice skating, swim)
Clinical classification
Classification by severity of exacerbation
Classification by recurrent, severe attacks
• Brittle asthma
Type 1 :
Brittle asthma is a
disease with wide peak
flow variability, despite
intense medication.
Type 2:
Brittle asthma is
background well-controlled
asthma with sudden severe
exacerbations.
Status asthmaticus
• It is an acute exacerbation of asthma that remains unresponsive
to initial treatment with bronchodilators. Status asthmaticus can
vary from a mild form to a severe form with bronchospasm,
airway inflammation, and mucus plugging that can cause
difficulty breathing, carbon dioxide retention, hypoxemia, and
respiratory failure.
• Patients report chest tightness, rapidly progressive shortness of
breath, dry cough, and wheezing and may have increased their
beta-agonist intake (either inhaled or nebulized) to as often as
every few minutes.
Pathogenesis
Overview:
Sensitization to allergen
Re-exposure to allergen
Histological changesIn the epithelial basement membrane occur over time. The
basement membrane is a complex structure that separates endothelial
cells from underlying stroma. The membrane provides tensile strength
and physical support to surrounding structures. It also function as a
filter and a site for cell attachment. In a classic study by Hogg in 1982,
the width of the basement membrane was shown to thicken in
asthmatics over time. The width seen in asthmatics is 17.5 μm,
whereas that seen in healthy subjects is 7 μm. Airway remodeling has
been detected pathologically. Declines in pu1monary function over time
can progress to chronic
Clinical Manifestations
Common symptoms: wheezing, feelings of tightness of the chest, dyspnea,
cough, and increased sputum production. Some patients have only a
chronic dry cough, and others have a productive cough. Sputum is often
thick, tenacious, scant, and viscid (sticky).
Especially in children, cough is often the earliest sign of
exacerbation of asthma. Wheezing is caused by vibration in narrowed
airways, which act like the vibrating reed of a wind instrument, yielding a
musical sound.
Physical findings vary with the severity of the attack.
1.) A mild attack:Associated with a random monophonic expiratory
wheezing(throughout the chest) associated with airway narrowing,
tachycardia, and tachypnea. Tachycardia is an early sign of hypoxemia.
{Wheeze: The area in which they are heard best is indicative of the area
of obstruction (e.g., if they are heard best at the mouth, this is indicative
of large airway obstruction)}.
2.) A more severe attack:
Its requiring medical assistance may be accompanied by the use
of accessory muscles of respiration, intercostal retractions, distant
breath sounds with inspiratory wheezing, orthopnea, agitation,
tachypnea, and tachycardia.
3.)Severe state:
The patient may appear cyanotic, agitated, restless, and
confused.
Physical findings
Common Signs and symptoms:
Diagnosis The diagnosis of asthma is based on physical findings, sputum
examination, pulmonary function tests, blood gas analysis, and chest
radiography.
Radiographic findings: May be normal or may show evidence of
hyperinflation with flattening of the diaphragm in progressive
disease.
Abnormal physical findings: Include cough, wheezing, a hyperinflated
chest, and decreased breath sounds.
Asthmatic sputum samples:Charcot-Leyden crystals (formed from
crystallized enzymes from eosinophilic membranes), eosinophils,
and Curschmann spirals(mucous casts of bronchioles).
Forced expiratory volumes: Decrease during asthma attacks.
PEFR: is the maximal flow of expired air attained during a forced vital
capacity (FVC) procedure.The evaluation of asthma should include
the measurement of forced expiratory volume over 1 second (FEV1),
FVC, and the ratio FEV1/FVC before and after administration of a
short-acting bronchodilator. Airflow obstruction is indicated by a
FEV1/FVC ratio of less than 75%.
Determination of allergens: It is done by skin testing or inhalation of
suspected allergens. Skin testing is usually more helpful in
young patients who have extrinsic asthma.
Bronchial provocation testing : with histamine or methacholine may
be useful in confirming the diagnosis of asthma in certain cases
A complete blood cell count: can show an elevated number of white
blood cells (WBCs) with increased eosinophils. Eosinophils are
prominent in the cellular infiltrate of the bronchioles, the sputum,
and the peripheral blood. (A fall in the total eosinophil count is a
valuable measure of effectiveness of corticosteroid treatment.
With effective treatment, the total eosinophil count is depressed
below 10/ μl )
Differential diagnosis
Treatment initiation by severity
Treatment modification
Treatment
Prevention 1. It’s important to minimize exposure to allergens.
2. Smoke and asthma are a bad mix. Minimize exposure to all
sources of smoke, including tobacco, incense, candles, fires, and
fireworks.
3. Do what you can to stay well. Avoid close contact with people who
have a cold or the flu.
4. Whether you’re at home, work, or traveling, there are specific
measures you can take to allergy-proof your environment and
reduce the risk of having asthma.
5. Get a flu shot every year to protect against the flu virus, which
almost always makes asthma much worse for days to weeks.
6. If you have exercise-induced asthma or are planning vigorous
exercise or exercise in cold, humid, or dry environments, prevent
exercise-induced asthma by following doctor's advice
regarding asthma treatment (usually by using an asthma
inhaler containing the drug albuterol).
References 1. Text book of pathophysiology by Copstead, Lee Ellen
2. http://www.aafa.org
3. http://www.worldallergy.org
4. http://www.who.int/topics/asthma
5. www.lung .org
6. www.webmd.com /asthma
7. www.mayoclinic.org/diseases/asthma
8. en.wikipedia.org/wiki/Asthma
9. www.asthmaaustralia.org.au