CC | Obstructive Respiratory Complications

Core Concept: Expiratory Airflow Resistance Obstructive lung diseases—bronchiectasis, cystic fibrosis (CF), asthma, and COPD—share increased expiratory airflow resistance from airway obstruction or narrowing. Drug therapy plays a key role in their clinical management. 1. Bronchiectasis: Mucus Stasis Pathophysiology & Presentation: Inflammation destroys elastic and muscular wall structures, causing permanent dilation and impaired mucus clearance. It presents as a persistent cough with thick, purulent sputum. Massive hemoptysis is a life-threatening complication. Care: CT scan is the gold standard. Care involves antibiotics (minimum 14 days), bronchodilators, and ACTs with hydration (2-3 L/day). 2. Cystic Fibrosis (CF): Ion Transport Defect Pathophysiology & Presentation: An autosomal recessive CFTR mutation disrupts sodium and chloride transport, producing thick, dehydrated mucus that plugs respiratory, GI, and reproductive ducts. This causes progressive organ scarring, pancreatic insufficiency, and malabsorption. Care: Sweat chloride testing is the gold standard. Management relies on aggressive ACTs and mucus-liquefying medications (dornase alfa), combined with pancreatic enzyme replacement before meals and mutation-specific CFTR modulators. 3. Asthma: Reversible Airflow Hyperreactivity Pathophysiology & Presentation: Inflammation involves mast cells and eosinophils. Triggers cause an early IgE-mediated bronchospasm, often followed by a late-phase response 4-6 hours later. Signs include wheezing, dyspnea, and cough. A sudden absence of wheezing ("silent chest") is an emergency. Care: Spirometry confirms reversibility (>12% and >200 mL FEV1 improvement post-bronchodilator). Inhaled corticosteroids (ICS) are first-line anti-inflammatories, often paired with LABAs. SABAs provide rescue relief, and patients follow an Asthma Action Plan based on peak flow zones. 4. COPD: Progressive Airflow Limitation Pathophysiology & Presentation: Non-reversible airflow limitation is driven by chronic exposure to toxins, mainly smoking. Inflammation causes alveolar destruction (emphysema), goblet cell hyperplasia, and loss of elastic recoil. It presents with progressive exertional dyspnea, chronic cough, and a "barrel chest". Care: Diagnosed when post-bronchodilator FEV1/FVC is <70%. Key care includes smoking cessation and stepwise inhaled drugs (LAMAs, LABAs, ICS). Calorie-dense nutrition combats cachexia, while pursed-lip breathing reduces air trapping.