Bronchial Asthma: Pathophysiology, Immunopathogenesis, Classification

Bronchial asthma: 

 Asthma may be defined as a disorder characterized by chronic airway inflammation and increase airway responsiveness resulting in sign of wheeze, cough, chest tightness & dyspnoea.

Pathophysiology of bronchial asthma:

Occurs due to external stimulus, such agents are –

•      Biological agents
•      Environmental /chemical agent
•      Virus

Immunopathogenesis of Bronchial Asthma:

• When a person exposed to antigen it stimulates production of antibody ( reaginic antibody – IgE) and bound to mast cell surface. 
• When re-exposure to that antigen than antigen –antibody reaction occur and triggers release of some chemical mediators from stored granules of mast cell and also helps in the synthesis and release of other mediators.

Types of bronchial asthma: 

There are various types of bronchial asthma.

1. Asthma associated with specific allergic reaction:

Criteria:

• Very early onset.
• Extrinsic type.
• Atopic individual.

Avoid of allergens – we prevent asthma. Here type I reaction occur involving IgE Antibody.

2. Asthma not associated with known allergy:

Criteria:

• Late onset.
• Intrinsic type.
• Non-atopic. (Not individual) occurs in a group.

3. Exercise induced asthma: Criteria: Within a few minutes asthma develops.

4. Asthma associated with chronic obstructive pulmonary disease.

• Chronic bronchitis
• Pulmonary emphysema

Asthma may also be classified into:

1. Intermittent
2. Persistent –

• Mild
• Moderate
• Severe

3. Acute

• Mild
• Moderate
• Severe ( Status asthmaticus)

4. Special variant –

• Seasonal
• Drug induced 
• Exercise induced
• Cough variant and Pregnancy asthma