CC | PRIMER Lower Resp. Complications

1. Lower Respiratory Infections: Pneumonia & Tuberculosis (TB) Pneumonia: Acute lung parenchymal infection where pathogens invade via aspiration, inhalation, or blood. Inflammation increases vascular permeability, causing capillary leakage and alveolar fluid consolidation, impairing gas exchange. Clinical Rule: Initiate empiric antibiotic therapy immediately upon suspicion to reduce mortality; adjust only after culture results. Prevent aspiration pneumonia by elevating the head of the bed to ≥30° and checking the gag reflexes. Tuberculosis (TB): Airborne disease caused by M. tuberculosis. LTBI vs. Active TB: Latent TB (LTBI) is asymptomatic, non-infectious, has normal chest x-rays, and requires single-drug therapy (e.g., isoniazid). Active TB is infectious, symptomatic, and treated with a 4-drug regimen (isoniazid, rifampin, pyrazinamide, ethambutol). Clinical Priority: Due to the rise of multidrug-resistant strains (MDR-TB), Directly Observed Therapy (DOT) is the standard of care for non-adherent patients. 2. Acute Pleural & Trauma Emergencies Tension Pneumothorax: A life-threatening emergency where air enters the pleural space on inspiration but cannot escape, causing positive pressure, lung collapse, and mediastinal shift that compresses the heart and unaffected lung. Manifestations: Severe dyspnea, tachycardia, and tracheal deviation. Requires immediate needle decompression and chest tube insertion. Flail Chest: Fracture of ≥3 consecutive ribs in ≥2 places, causing paradoxical chest wall movement (moves inward during inspiration, outward during expiration). Treat with oxygen, analgesics, and positive pressure ventilation to stabilize the segment. 3. Vascular & Blockage Emergencies: Pulmonary Embolism (PE) Pathophysiology: Blockage of pulmonary arteries by a thrombus (usually from lower-limb DVT), obstructing alveolar perfusion. Diagnosis & Management: Dyspnea is the most common symptom. A spiral CT scan is the gold standard for diagnosis (or V/Q scan if contrast is contraindicated). Key Care: Administer immediate anticoagulation (LMWH or IV heparin) to prevent clot extension; long-term therapy (e.g., warfarin) continues for ≥3 months. 4. Oncologic Malignancies: Lung Cancer NSCLC vs. SCLC: Non-Small Cell (84%) grows moderately and is treated surgically if diagnosed in early stages (I–IIIA). Small Cell (SCLC, 13%) is highly aggressive, spreads early via blood and lymph (frequently to the brain), and is treated primarily with systemic chemotherapy and prophylactic cranial irradiation.