[Interstitial pneumonitis followed by syndrome of inappropriate antidiuretic hormone secretion induced by amiodarone therapy for dilated cardiomyopathy: a case report].

An 87-year-old man had been treated under a diagnosis of idiopathic dilated cardiomyopathy and sick sinus syndrome since 1996. His heart failure was worsened by atrial fibrillation in August 2004. He received amiodarone from October 2004. He was admitted to our hospital with shortness of breath in February 2005. Chest radiography revealed a diffuse reticular shadow in the right lung field and pleural effusion. The diagnosis was interstitial pneumonitis induced by amiodarone. However, 10 days after the discontinuation of amiodarone, the serum sodium concentration fell to 114mEq/l. The blood and urine chemical data were consistent with syndrome of inappropriate antidiuretic hormone secretion (SIADH). The serum sodium concentration improved with fluid restriction. Clinicians should be aware that SIADH may occur during amiodarone therapy.