Pleurisy: Pathophysiology, Complications, and Management

Pleurisy (pleuritis) is inflammation of the pleural membranes—visceral (lung surface) and parietal (chest wall)—causing sharp, respiration-synchronous chest pain.

Pathophysiology

• Inflammation → ↑ vascular permeability → pleural effusion (exudative: high protein, LDH, cells).
• Inflamed surfaces rub → sharp pleuritic pain (somatic innervation of parietal pleura).
• Effusion accumulates → compresses lung → restrictive physiology, dyspnea.
• Fibrin deposition → adhesions, loculations, trapped lung (chronic).

Etiologies

• Infection: Viral (most common), bacterial (parapneumonic), TB, fungal
• Autoimmune: SLE, RA, vasculitis
• Malignancy: Mesothelioma, metastatic (lung, breast, lymphoma)
• Pulmonary embolism: Infarction → pleural inflammation
• Drug-induced: Nitrofurantoin, hydralazine, procainamide, checkpoint inhibitors
• Trauma / post-cardiac injury syndrome (Dressler's)
• Asbestos (benign pleural effusion, plaques)

Complications

• Empyema: Pus in pleural space (positive Gram stain/culture, pH <7.2, glucose <60). Requires drainage + antibiotics.
• Fibrothorax / trapped lung: Chronic fibrotic peel prevents re-expansion; may need decortication.
• Respiratory failure: Large effusion + underlying lung disease.
• Chronic pain: Nerve sensitization, intercostal neuralgia.

Diagnosis

• CXR: blunted costophrenic angle, effusion, pleural thickening
• CT chest: pleura, parenchyma, mediastinum, loculations
• Thoracentesis: Light's criteria (exudate vs. transudate), cell count, culture, cytology, pH, glucose, ADA (TB), amylase (pancreatic)
• Pleural biopsy (image-guided or thoracoscopic) if exudate undiagnosed

Management

• Treat underlying cause: Antibiotics, anticoagulation, immunosuppressants, oncology.
• Symptomatic: NSAIDs (indomethacin classic), acetaminophen, opioids if severe.
• Thoracentesis: Diagnostic + therapeutic if large/symptomatic effusion.
• Chest tube + fibrinolytics / VATS decortication: Empyema, complicated parapneumonic, trapped lung.
• Pleurodesis: Recurrent malignant effusion (talc, doxycycline).

Most viral pleurisy resolves in 1–2 weeks. Persistent/recurrent effusion mandates thorough investigation.