A 58-year-old man with COPD GOLD Stage III presents with acute exacerbation. Which is the most common cause of acute exacerbation in COPD patients in India?

Explanation

## Causes of Acute COPD Exacerbation **Key Point:** Respiratory tract infections (RTI) — both bacterial and viral — account for 50–80% of acute COPD exacerbations, making them the single most common precipitant globally and in India. ### Epidemiology of COPD Exacerbation Triggers | Cause | Frequency | Mechanism | Common Pathogens | |-------|-----------|-----------|------------------| | **Respiratory tract infection** | 50–80% | Viral or bacterial colonization → airway inflammation, mucus hypersecretion | *Streptococcus pneumoniae*, *Haemophilus influenzae*, *Moraxella catarrhalis*, rhinovirus, influenza | | **Air pollution** | 10–20% | Particulate matter and oxidative stress trigger airway inflammation | PM₂.₅, NO₂, SO₂ | | **Medication non-compliance** | 5–10% | Loss of anti-inflammatory and bronchodilator coverage | Steroid/LABA withdrawal | | **Cardiac causes** | 5–10% | Acute heart failure, arrhythmia, MI | Acute decompensation, AF | | **Pulmonary embolism** | 2–5% | Thromboembolism in immobilized patients | VTE | **High-Yield:** In India, the combination of RTI + air pollution exposure is particularly significant. During winter months and in urban areas with high pollution, exacerbations surge due to both infectious and environmental triggers. **Clinical Pearl:** Viral infections (rhinovirus, influenza, RSV, COVID-19) are increasingly recognized as major triggers. Bacterial superinfection often follows viral RTI, making the distinction clinically important for antibiotic stewardship. **Mnemonic:** **ABCDE of COPD exacerbation causes** — **A**irway infection (most common), **B**ronchial obstruction (mucus plugging), **C**ardiac (heart failure), **D**rugs (non-compliance), **E**nvironment (pollution).