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