Asbestos-related lung disease

Idiopathic pulmonary fibrosis is a chronic, progressive fibrosing lung disease of unknown cause defined by a usual interstitial pneumonia (UIP) pattern, presenting with progressive dyspnea, dry cough, bibasilar Velcro crackles, and clubbing in older smokers. A definite UIP pattern on high-resolution CT confirms the diagnosis without biopsy; management centers on antifibrotic therapy (pirfenidone or nintedanib), oxygen, and early lung transplant referral, since corticosteroids are not indicated and median survival is 3 to 5 years.

Interstitial lung disease (ILD), also called diffuse parenchymal lung disease, is a diverse group of nonmalignant disorders causing inflammation and scarring of the alveolar interstitium, presenting as subacute to chronic exertional dyspnea and nonproductive cough. Diagnosis rests on pulmonary function testing plus high-resolution CT pattern recognition; management is exposure removal, glucocorticoids for inflammatory disease, antifibrotic therapy for progressive fibrotic disease, oxygen for hypoxemia, and early transplant referral.

Silicosis is a fibrotic occupational lung disease caused by inhaling crystalline silica dust, producing upper-zone nodular opacities and progressive dyspnea in exposed workers. Diagnosis rests on a compatible exposure history plus a characteristic imaging pattern. No agent reverses the fibrosis, so management is supportive: exposure cessation, oxygen for hypoxemia, vaccination, isoniazid prophylaxis for latent tuberculosis, and transplant evaluation for advanced disease.

Pleural effusion is fluid accumulation in the pleural space from an imbalance of hydrostatic/oncotic pressure or increased capillary permeability; Light's criteria separate exudates from transudates, and management treats the underlying cause, with therapeutic thoracentesis, chest tube drainage, or pleurodesis for symptomatic or complicated effusions.

Lung cancer is the leading cause of cancer death worldwide, split into non-small cell lung cancer (NSCLC, 80% of cases: adenocarcinoma, squamous cell, large cell) and small cell lung cancer (SCLC, 10-15%), both driven overwhelmingly by cigarette smoking. Diagnosis requires tissue histopathology, staging drives treatment (TNM staging for NSCLC, limited versus extensive stage for SCLC), and management ranges from lobectomy in early-stage disease through concurrent chemoradiation and consolidation immunotherapy in locally advanced disease to targeted tyrosine kinase inhibitors, immune checkpoint inhibitors, or platinum-based chemotherapy in metastatic disease.

Hypersensitivity pneumonitis is a mixed type III/IV immune reaction to repeated inhalation of an organic antigen in a sensitized host, producing noncaseating granulomas and bronchiolocentric inflammation. Removal of the offending antigen is the essential first step in treatment; glucocorticoids are added for significant hypoxemia or symptom burden, and unremitting exposure can progress to fibrotic lung disease indistinguishable from idiopathic pulmonary fibrosis.

Sarcoidosis is a multisystem granulomatous disease of unknown cause defined by noncaseating granulomas, most commonly involving the lungs and hilar lymph nodes. Most patients are asymptomatic or have a self-limited course staged by chest radiograph; symptomatic organ-threatening disease is treated with systemic glucocorticoids, with methotrexate or another steroid-sparing agent added for glucocorticoid-refractory or glucocorticoid-intolerant disease.