Most common cause of idiopathic interstitial pneumonia is: (A) Sarcoidosis, (B) Organizing pneumonia, (C) Idiopathic pulmonary fibrosis, (D) Lipoid pneumonia
Answer is C. Idiopathic pulmonary fibrosis is the most common form of idiopathic interstitial pneumonia.It is characterised by exeional dyspnea,non productive cough,inspiratory crackles with or without digital clubbing.HRCT show patchy,predominantly basilar,subpleural reticular opacities,traction bronchiectasis and honeycombing.Pulmonary function tests often reveal a restrictive pattern. Reference:Harrison' s medicine-18th edition,page no:2165.