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Background
Amiodarone is an iodine-rich antiarrhythmic medication commonly used to manage various cardiac rhythm abnormalities. Despite its efficacy, amiodarone is associated with a range of potential side effects affecting multiple organ systems. While these side effects are typically mild, 10–15% of patients may need to discontinue the medication due to toxicity [1]. The most common adverse effects associated with long-term use include thyroid dysfunction, corneal microdeposits, and pulmonary and hepatic toxicity [2]. Peripheral neuropathy is another known complication, affecting approximately 10% of patients on amiodarone therapy [3].
Although neuromyopathy is a rare complication of amiodarone, it should be considered in patients presenting with relevant symptoms. Here, we present a case of amiodarone-induced neuropathy following two years of treatment with 400 mg of oral amiodarone.
Case presentation
A 68-year-old male presented to our institution with a chief complaint of subacute bilateral leg pain and weakness, resulting in complete loss of independent ambulation. His medical history included arrhythmogenic right ventricular dysplasia complicated with ventricular tachycardia, which required the implantation of an ICD in 2009, with device replacement in 2019. He also had a history of infectious endocarditis due to Staphylococcus aureus, treated with ICD extraction and initiation of 400 mg of amiodarone therapy for rate control in 2021.
Two years after the initiation of amiodarone therapy, the patient experienced a transient episode of tremor, which was initially overlooked. This was followed by the development of bilateral leg pain and weakness, progressively leading to functional impairment. The pain exhibited a migratory pattern but remained localized to the lower limbs, without any associated bowel or bladder dysfunction.
On physical examination, segmental muscle strength in the lower limbs was 2/5, with 3/5 strength in ankle dorsiflexion. Osteotendinous reflexes were absent bilaterally, and tactile hypoesthesia extended up to the knees.
The biological assessment revealed normal levels of creatine kinase and C-reactive protein. Additionally, vitamin B12 levels were within the reference range, and viral serologies for hepatitis B (HBV), hepatitis C (HCV), HIV, syphilis, Epstein–Barr virus (EBV), and cytomegalovirus (CMV) were negative. Thyroid-stimulating hormone (TSH), calcium, magnesium, and liver function tests were all within normal limits.
Spinal MRI findings were unremarkable.
Electromyography (EMG) demonstrated a non-length-dependent sensorimotor...