ILD

ILD refers to a diverse group of lung disorders characterized by inflammation and/or fibrosis of the lung interstitium, often with progressive scarring and impaired gas exchange. It includes idiopathic forms as well as diseases linked to exposures, medications, or systemic conditions. Fibrosing ILDs tend to cause restrictive physiology and reduced diffusing capacity; inflammatory or granulomatous ILDs may respond to immunosuppression.

Common categories include idiopathic interstitial pneumonias such as idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia; hypersensitivity pneumonitis; sarcoidosis; and pneumoconioses like asbestosis. Drug-induced ILD and radiation pneumonitis are also recognized. Diagnosis typically requires a multidisciplinary approach using clinical history, pulmonary function tests, high-resolution CT, serology, and sometimes bronchoscopy or biopsy.

Symptoms usually include progressive dyspnea on exertion and a chronic dry cough. Exam may reveal bibasilar end-inspiratory crackles and, in some diseases, clubbing. PFTs often show a restrictive pattern with reduced DLCO. HRCT patterns help classify disease (eg, UIP, NSIP) and guide management.

Management focuses on removing triggers, preventing infections, and slowing progression. Antifibrotic drugs such as nintedanib or pirfenidone are standard for fibrosing ILDs, including IPF. Corticosteroids and other immunosuppressants are used for inflammatory ILDs in selected cases. Supportive care includes oxygen, pulmonary rehabilitation, vaccinations, and, for advanced disease, lung transplantation. Prognosis varies by subtype and individual factors; IPF generally has a poorer outcome than many inflammatory ILDs.