20. Bronchial asthma Flashcards
What is bronchial asthma?
It is a chronic inflammatory disorder of the airways characterized by infiltration of mast cells, eosinophils, and lymphocytes in the airways + recurrent episodes of wheezing, coughing, and dyspnea + often reversible airflow limitation + airway hyperresponsiveness.
What are the main triggers of airway inflammation in asthma?
The main triggers of airway inflammation in asthma are inhaled allergens, which activate mast cells to trigger histamine and leukotrienes and Th2 cells to activate eosinophilic activation and release inflammatory mediators.
What are the pathological changes in asthma?
In asthma, the airways will narrow, causing wheezing sounds due to bronchoconstriction, thickening of the wall (edema), and mucus plug.
What is the pathomechanism of airflow limitation in asthma?
The pathomechanism of airflow limitation in asthma is mainly due to bronchoconstriction caused by allergens triggering inflammatory mediators such as histamine, leukotrienes, and prostaglandins.
How is airflow limitation in asthma reversible?
Airflow limitation in asthma is reversible by bronchodilators.
What are other factors that can cause limited airflow in asthma?
- Edema formation,
- mucus hypersecretion,
- structural changes such as hypertrophy and hyperplasia of bronchial smooth muscle,
- tissue fibrosis.
What is airway hyperresponsiveness?
It is an exaggerated bronchoconstrictor response to triggers such as exercise, cold air, and stress.
How is airway hyperresponsiveness measured?
It is measured by responsiveness to inhaled methacholine, adenosine, and mannitol.
What reduces airway hyperresponsiveness?
Anti-inflammatory therapy reduces airway hyperresponsiveness.
What is airway “remodeling” in chronic asthma?
- bronchial smooth muscle hypertrophy and hyperplasia,
- collagen deposition,
- increased mucous glands and mucus production,
- increased vascularity.
What are the classifications of asthma?
- Severity (intermittent, mild, moderate, severe),
- control level (controlled, partly controlled, uncontrolled),
- etiology (extrinsic = allergic, intrinsic = non-allergic).
What is the most important classification of asthma?
Control level is the most important classification of asthma.
What are the four methods of diagnosing asthma?
- History and patterns of symptoms,
- lung function measurements,
- measurement of airway responsiveness (reversibility and/or hyperreactivity).
- measurement of allergic status to identify risk factors
What are the symptoms of asthma?
Symptoms of asthma include :
- wheezing,
- coughing,
- dyspnea,
- tachypnea,
- chest tightness,
- increased sputum production
How does asthma differ from COPD in terms of symptoms?
Asthma can be completely symptomless in between exacerbations, whereas COPD causes continuous symptoms.