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.
What are the methods used for lung function measurements in asthma diagnosis?
The methods used for lung function measurements in asthma diagnosis include
- spirometry,
- peak expiratory flow measurement,
- body plethysmography,
- airway hyperreactivity testing,
- airflow limitation reversibility testing.
What is spirometry?
Spirometry is a lung function measurement method where the patient breathes forcefully through their mouth into an external device to measure airflow.
What are the in vivo tests used for allergy testing in asthma?
Allergy skin (prick) test and bronchial challenge test (specific).
What are the in vitro tests used for allergy testing in asthma?
Serum total/specific IgE levels, eosinophilic cation protein, histamine, tryptase, etc.
What is the marker of airway inflammation that is produced by epithelial and alveolar cells?
Exhaled NO.
What does elevated exhaled NO reflect in asthma?
Eosinophilic airway inflammation.
What is the marker of airway inflammation that correlates with the inflammatory response but is not practical?
Sputum eosinophils.
What are the ways to identify and reduce exposure to risk factors in asthma?
Reduce exposure to indoor allergens, avoid tobacco smoke, identify irritants in the workplace, avoid vehicle emission, explore the role of infections on asthma development, especially in children and young infants.
What are the types of medications used in asthma?
Rescue medication / controller medication
Why are inhaled drugs preferred over oral drugs in asthma?
Inhaled drugs are better due to rapid onset, less amount needed, better tolerated, and act locally.
What are the rescue medications used in asthma?
- Short-acting beta-agonists (SABA)
- anticholinergics.
- theophyllines (IV)
What are the controller medications used for long-term management of asthma?
- Inhaled corticosteroids (ICS),
- Leukotriene modifiers
- Anti-IgE
- Long-acting beta-agonists (LABA),
- Theophyllines (per os)
What are rescue medications used for in the treatment of asthma?
They are used in emergencies to provide quick relief of symptoms for 4-6 hours.
What is the effect of rescue medications on the airways?
-They cause bronchodilation by relaxing bronchial smooth muscle,
- and have anti-inflammatory effects such as decreasing mast cell degranulation, vascular permeability, and neutrophilic inflammation,
- and increasing mucociliary clearance.
What are the drugs used as SABA rescue medications?
Salbutamol, terbutaline, and fenoterol.
What are controller medications used for in the treatment of asthma?
They are used to prevent asthma symptoms and reduce the frequency and severity of asthma attacks.
What is the mechanism of action of inhaled corticosteroids?
They have cellular actions that lead to protein synthesis and thus anti-inflammatory effects.
What are the examples of inhaled corticosteroids used as controller medications?
- Beclomethasone,
- budesonide,
- fluticasone (low bioavailability),
- ciclesonide (prodrug that is enzymatically activated in the lung).
What are the types of anti-IgE biologics used as controller medications?
- Anti-IgE (omalizumab),
- anti-IL-5 (mepolizumab),
- anti-IL-5R (benralizumab).
What are the types of long-acting bronchodilators used as controller medications?
Long-acting beta-2 agonists (LABA) and theophyllines (per os).
