ADVERSE DRUG REACTION Amiodarone toxicity presenting as pulmonary mass and peripheral neuropathy: the continuing diagnostic challenge

A 64 year old man receiving long term amiodarone treatment presented with dyspnea, cough, and weight loss. Radiographs and computed tomography showed a lung mass with associated multiple pulmonary nodules. Biopsies of the pulmonary mass showed foamy histiocytes without malignant cells. However, findings on FDG-PET scan were consistent with a malignant tumour. These findings on computed tomography and PET scan and the unusually late resolution of the pulmonary lesions after withdrawal of amiodarone treatment posed a challenging diagnostic problem. A miodarone induced pulmonary toxicity (AIPT) typically presents as a non-specific interstitial pneumonia. Less commonly, AIPT can manifest as an organising pneumonia, resulting in a more patchy interstitial inflamma-tion or nodular areas of consolidation.1–3 The differential diagnosis on computed tomography (CT) of such a mass or nodules centres on a neoplasm as illustrated in the following case report. CASE REPORT A 64 year old man was admitted to the medical ward for evaluation of low grade fever, cough, pleuritic chest pain, and weakness. The patient had lost 10 kg in weight. He was a lifelong non-smoker with no occupational exposures. His medical history included coronary artery disease, arterial hypertension, stable congestive heart failure, and ventricular tachycardia. A cardioverter defibrillator had been implanted seven years ago and amiodarone 400 mg daily was given (total cumulative dose of 950 g amiodarone). Attempts to decrease the dose of amiodarone were associated with frequent discharges of the cardioverter. Thus, the 400 mg dose that proved to be efficient was prescribed during the past seven years. Drugs at the time of the present admission included ramipril, amiodarone, carvedilol, isosorbide dini-trate, furosemide, digoxin, simvastatin, omeprazole, spirono-lactone, and warfarin