Amiodarone induced hyponatremia masquerading as syndrome of inappropriate antidiuretic hormone secretion by anaplastic carcinoma of prostate.

Pinaki Dutta,Girish Parthan,Anuradha Aggarwal,Fabio Rotondo,Kalman Kovacs,Nandita Kakkar,Anil Bhansali,Santosh Kumar

doi:10.1155/2014/136984

Abstract

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia. The usual causes are malignancies, central nervous system, pulmonary disorders, and drugs. Amiodarone is a broad spectrum antiarrhythmic agent widely used in the management of arrhythmias. The different side effects include thyroid dysfunction, visual disturbances, pulmonary infiltrates, ataxia, cardiac conduction abnormalities, drug interactions, corneal microdeposits, skin rashes, and gastrointestinal disturbances. SIADH is a rare but lethal side effect of amiodarone. We describe a 62-year-old male who was suffering from advanced prostatic malignancy, taking amiodarone for underlying heart disease. He developed SIADH which was initially thought to be paraneoplastic in etiology, but later histopathology refuted that. This case emphasizes the importance of detailed drug history and the role of immunohistochemistry in establishing the diagnosis and management of hyponatremia due to SIADH.

Highlights

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia
SIADH was first reported by Schwartz et al in 1957 in patients with bronchogenic carcinoma and meningitis [1]
In 1971 four cases of chlorpropamide-induced hyponatremia were described by Weissman et al [5]

Summary

Introduction

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is one of the most common causes of hyponatremia. There are a few case reports of SIADH in patients with small cell and anaplastic carcinoma of prostate [2]. The adverse effect profile is very broad; there are very few cases of hyponatremia due to SIADH reported with this drug [7,8,9,10,11,12,13,14,15,16] We describe one such case in an elderly male which was initially thought to be due to ectopic secretion of vasopressin by an anaplastic carcinoma of prostate but later refuted by immunohistochemistry of the tumor and normalization of serum sodium level following omission of amiodarone

Case Report

Discussion

Findings

Months