[A case of idiopathic pulmonary fibrosis associated with bilateral pulmonary arterial thrombosis found at autopsy].

A 73-year-old woman admitted to the hospital with dyspnea on exertion. Chest radiography revealed a diffuse interstitial shadow; PaO2 was 72 Torr, and PaCO2 was 41 Torr. Laboratory examination results were compatible with idiopathic pulmonary fibrosis (IPF). Prednisolone relieved the dyspnea, but tapering of the drug led to a recurrence of this symptom. Pulse therapy was started and azathioprine was added to the corticosteroid. Over the course of 6 months of treatment, the patient's respiratory function remained fairly stable. Then respiratory distress was induced by an attack of atrial fibrillation, with relief provided by anti-arrhythmic drugs and large doses of corticosteroids. The patient died suddenly 3 weeks later. An autopsy revealed large thrombi in both pulmonary arteries with 90% stenosis. Parts of the thrombi were organized, which suggests that 2-3 weeks had elapsed since initial thrombus formation. Histological examination of lung tissue showed usual interstitial pneumonia. Pulmonary thromboembolism should be considered in patients with IPF if respiratory distress suddenly and unexpectedly worsens.