Asthma + COPD Flashcards
(8 cards)
intro persistent airway inflammation
Asthma and chronic obstructive pulmonary disease (COPD) are prevalent respiratory conditions marked by persistent airway inflammation and airflow limitation. While asthma is typically immunologically mediated and reversible, characterised by episodic symptoms and airway hyperresponsiveness, COPD is a progressive, largely irreversible disorder predominantly associated with long-term exposure to harmful agents such as tobacco smoke. Effective clinical management relies on a nuanced understanding of their distinct pathophysiology and the pharmacodynamics and pharmacokinetics of available therapies.
2nd para - asthma pathology
Asthma is driven by a T-helper 2 (Th2)-skewed immune response, with interleukins (IL-4, IL-5, IL-13) promoting eosinophilic inflammation, IgE production, mucus hypersecretion, and bronchial hyperreactivity. Mast cell degranulation and the release of histamine and cysteinyl leukotrienes (LTC₄, LTD₄) contribute to bronchoconstriction and mucosal oedema. Acute symptom relief is achieved with short-acting β₂-adrenoceptor agonists (SABAs) such as salbutamol, which activate Gs-coupled β₂ receptors, increasing intracellular cAMP and inducing smooth muscle relaxation via protein kinase A (PKA). Long-term control requires combination therapy with long-acting β₂-agonists (LABAs; e.g., formoterol) and inhaled corticosteroids (ICS), as LABA monotherapy in asthma is contraindicated due to safety concerns.
3rd para - asthma effective treatment
ICS such as budesonide are foundational in maintenance therapy. By binding glucocorticoid receptors and modulating gene transcription, they suppress pro-inflammatory cytokines and upregulate β₂-receptor expression. Leukotriene pathway inhibitors provide adjunctive control: montelukast blocks CysLT1 receptors, while zileuton inhibits 5-lipoxygenase, reducing leukotriene synthesis. In severe, treatment-refractory asthma, biologics such as omalizumab (anti-IgE), mepolizumab and benralizumab (anti-IL-5/IL-5R) target key mediators of type 2 inflammation.
4th para - asthma preffererd route of drug delivery
Inhalation is the preferred route of drug delivery, optimising local effects while minimising systemic exposure. However, systemic absorption still occurs, and factors such as lipophilicity, metabolic stability, and receptor affinity influence therapeutic duration and efficacy.
5th para - COPD pathology
COPD encompasses chronic bronchitis—defined by mucus hypersecretion and goblet cell hyperplasia—and emphysema, which involves protease-mediated alveolar wall destruction and reduced elastic recoil. Neutrophilic inflammation, oxidative stress, and impaired mucociliary clearance drive progressive airway remodelling. Symptoms include exertional dyspnoea, chronic cough, and sputum production, with advanced stages presenting hypoxaemia, hypercapnia, and cor pulmonale.
6th para - COPD effective treatment
Smoking cessation is the single most effective intervention to slow disease progression. Pharmacologically, bronchodilators are central. LABAs (e.g., indacaterol), long-acting muscarinic antagonists (LAMAs; e.g., tiotropium), and fixed LABA/LAMA combinations improve airflow and reduce exacerbation frequency. Muscarinic antagonists act via M3 receptor inhibition, reducing IP₃-mediated Ca²⁺ release and promoting airway smooth muscle relaxation. Methylxanthines like theophylline, once widely used, are now reserved due to their narrow therapeutic index and risk of adverse effects including arrhythmias and seizures.
7th para - ICS in COPD
ICS in COPD are reserved for patients with eosinophilic inflammation or frequent exacerbations. Their use must be balanced against the increased risk of pneumonia. Fixed-dose LABA/ICS combinations, such as salmeterol/fluticasone, are beneficial in reducing exacerbations, and triple therapy (LABA + LAMA + ICS) is indicated in those with persistent symptoms. Antibiotics are reserved for infective exacerbations, while prophylactic macrolides may be considered in select cases. Mucolytics like N-acetylcysteine are helpful in patients with chronic bronchitis. Antitussives are generally avoided unless cough is severely distressing, to preserve protective reflexes.
8th para - asthma-copd
Asthma-COPD overlap (ACO) refers to patients exhibiting characteristics of both diseases, such as bronchodilator responsiveness in smokers or eosinophilic inflammation in COPD. Lacking a universal definition, diagnosis is clinical and supported by biomarkers like fractional exhaled nitric oxide (FeNO) and peripheral eosinophil counts. Management is individualised, combining anti-inflammatory treatment with dual bronchodilation.
