[Case of unilateral organizing pneumonia induced by amiodarone pulmonary toxicity]

A 78-year-old man with diabetes mellitus, hyperthyroidism and congestive heart failure was admitted to our hospital because of dyspnea on effort. He had been taking 200 mg/day amiodarone for 2 years, in order to treat a intermitted ventricular tachycardia. His chest X rays showed the appearance of diffuse consolidation in the right lung field. At first severe pulmonary infection was suspected, and he was treated with antibiotics. In spite of the treatment, the chest X-ray findings did not improved. We thought of the possibility of interstitial lung disease, and performed bronchoalveolar lavage (BAL) and transbronchial lung biopsy (TBLB) from the right middle lobe. TBLB revealed the organizing pneumonia (OP). At the same time we observed that he had temporary sinus arrest and entered a stated of shock requiring intubation, temporary pacing and intra-aortic balloon pumping (IABP) . The coronary angiography (CAG) revealed no abnormalities and cardiac function was normal. Within two days his sinus rhythm recovered spontaneously. After cessation of amiodarone and administering steroid therapy, pulmonary shadows resolved quickly. Since there were no laboratory signs of connective tissue or infectious disease such as a normal autoimmune serology, antibody titers against Mycoplasma pneumoniae, Clamydia species, and BAL, TBLB cultures, etc, we considered that unilateral organizing pneumonia and temporary sinus arrest could be induced by amiodarone. The amiodarone pulmonary toxicity (APT) commonly courses pleural effusion and while it may be strictly unilateral, there are often diminutive contralateral foci visible on HR-CT. Steroids should be given for months and tapered prudently, otherwise APT may recur owing to the persistence of amiodarone in lung.