Alveolar hemorrhage is seen in all except-

IDIOPATHIC PULMONARY FIBROSIS PATHOGENESIS. The pathogenesis of idiopathic pulmonary fibrosis is unknown and the condition is diagnosed by excluding all known causes of interstitial fibrosis. However, a few shreds of evidence point toward the immunologic mechanism: 1. High levels of autoantibodies such as rheumatoid factor and antinuclear antibodies. 2. Elevated titers of circulating immune complexes. 3. Immunofluorescent demonstration of the deposits of immunoglobulins and complement on the alveolar walls in biopsy specimens. CLINICAL FEATURES. Middle-aged males are affected more frequently. The usual features are of respiratory difficulty beginning with dry cough and slowly progressing dyspnoea. More advanced cases may develop clubbing of fingers and cor pulmonale. A rapidly progressive form of the idiopathic pulmonary fibrosis with death within 6 weeks to 6 months is termed Hamman-Rich syndrome. Ref: Harsh Mohan - Textbook of Pathology, 6th Edition.page no.496