“Asthma is a disease characterized by airway inflammation & episodic reversible bronchospasm.”
What Is The Pathophysiology of Asthma?
Bronchoconstriction is associated with asthma & the immediate cause of it is the release of several mediators from IgE-sensitized mast cells & other cells involved in immunologic responses.
The antigen is presented to peripheral lymphoid tissue which causes synthesis of IgE. IgE in turn binds to mast cells & sensitizes it & other inflammatory cells as well. The challenging of these sensitized cells with antigen results into massive release of a variety of mediators which account for signs of bronchoconstrictor response in asthmatics.
The mediators released are;
- Leukotrienes LTC4, LTD4, LTB4 (Chemotactic mediator which attracts inflammatory cells to the airway)
- PGD2 (prostaglandins 2)
- Some enzymes like tryptase
These mediators lead to chronic inflammation which results into hyper-reactivity (mediated by Vagal Reflexes) to various inhaled substances like;
- Cold air
- Irritants like SO2
- Muscarinic agonists
What Are Therapeutic Strategies In Asthma?
Therapeutic strategies are done in two categories (bases upon onset of bronchospasm i-e acute or chronic);
- Pharmacological therapies
- Non-pharmacological therapies
What Are Non-Pharmacological Therapies In Asthma?
Non-pharmacological therapies include mainly…..
What Are Pharmacological Therapies In Asthma?
Pharmacological therapies include;
Bronchodilators / Reliever Drugs (Smooth Muscles Relaxants)
- Sympathomimetics (β-selective agonists)
- Muscarinic antagonists
- Leukotriene receptors blockers (Leukotriene receptors blockers have effects on both bronchoconstriction & inflammation but are used for prophylaxis only)
φ Acute bronchospasm must be treated promptly & effectively with bronchodilators!
- Corticosteroids (Long acting β-selective agonists improve response to corticosteroids so used with corticosteroids)
- Mast cell stabilizers
- Anti-IgE antibody
φ Chronic asthma is treated with anti-inflammatory agents, the most important of which are corticosteroids!
What Are Bronchodilators / Reliever Drugs?
Sympathomimetics (β-selective agonists)