Idiopathic interstitial pneumonias

Idiopathic interstitial pneumonias are diseases of the lung interstitium where the etiology is unknown. They constitute the largest group of interstitial lung diseases. Making a diagnosis can be challenging due to the diversity of clinical presentations and frequently, non-specific radiological and pathological findings. The most common form, idiopathic pulmonary fibrosis, has a poor prognosis with median survival of 3 years from diagnosis. There have been changes in the nomenclature of different individual entities over the years. Moreover, there is paucity of data on the best treatments available to manage this group of lung diseases. The nomenclature, clinical features, pathophysiology, diagnostic techniques, and prognosis of the idiopathic interstitial pneumonias are discussed in this review.