IPF

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia of unknown cause, and the most common form of idiopathic interstitial pneumonia. It is characterized histologically by usual interstitial pneumonia (UIP) and radiographically by subpleural and basilar predominant fibrosis.

Epidemiology and risk factors: IPF typically presents in adults aged 60 to 70, with a male predominance and a history of smoking in many cases. Genetic factors, including variations in the MUC5B promoter, modestly increase risk, while environmental exposures may contribute to disease development or progression.

Pathophysiology: The disease is thought to result from repeated injury to alveolar epithelium in genetically susceptible individuals, leading to aberrant wound healing and excessive deposition of extracellular matrix. The UIP pattern shows patchy fibrosis with architectural distortion, honeycombing, and fibroblastic foci, usually more prominent at the lung bases and subpleurally.

Clinical features: Patients commonly experience gradually worsening dyspnea on exertion and a dry cough. On examination, bibasilar Velcro-like crackles and digital clubbing may be present. Hypoxemia can worsen with activity, and pulmonary function tests typically reveal a restrictive defect with reduced diffusing capacity.

Diagnosis: IPF is a diagnosis of exclusion, requiring careful assessment to rule out other causes of interstitial lung disease. High-resolution CT is central for identifying a UIP pattern; in eligible patients, this may suffice without surgical biopsy. A multidisciplinary discussion among clinicians, radiologists, and pathologists supports a final diagnosis.

Treatment and prognosis: There is no cure. Antifibrotic therapies, pirfenidone and nintedanib, slow disease progression. Supportive care includes oxygen therapy as needed, pulmonary rehabilitation, vaccinations, and management of comorbidities. Lung transplantation is an option for eligible individuals. Median survival after diagnosis is commonly cited as 3–5 years, with substantial variability.