SHM Converge Scientific Abstract ePoster Gallery-Unusual Presentation of Amiodarone-Induced Thyrotoxicosis in a Heart Transplant Recipient

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This case describes a 66-year-old man with diabetes, advanced chronic kidney disease, hypertension, obstructive sleep apnea, ventricular tachycardia, and prior orthotopic heart transplant who had taken amiodarone for three years. He was hospitalized for acute cholecystitis and underwent laparoscopic cholecystectomy, after which he developed hyperactive delirium, confusion, hallucinations, weakness, anxiety, insomnia, intermittent tremors, and cold intolerance.<br /><br />Despite these symptoms, he remained hemodynamically stable with a normal sinus rhythm and a heart rate in the 60s throughout the illness. Neurologic evaluation, brain imaging, and testing for paraneoplastic encephalitis, seizures, and prion disease were unrevealing. Routine labs and cultures were normal. Thyroid studies, however, showed marked thyrotoxicosis with very high free T4 and T3 and suppressed TSH. Thyroid ultrasound demonstrated diffuse heterogeneous parenchyma, and thyroid autoantibodies were negative.<br /><br />His thyrotoxicosis did not improve with methimazole, steroids, or propranolol, so he underwent urgent total thyroidectomy. Pathology confirmed type 1 amiodarone-induced thyrotoxicosis. After surgery, his mental status gradually improved as thyroid hormone levels normalized. He was discharged on postoperative day 8 fully alert and oriented and continued on levothyroxine.<br /><br />The key teaching point is that heart transplant recipients may not show the usual cardiovascular signs of thyrotoxicosis, such as tachycardia or arrhythmia, because of cardiac denervation after transplant. As a result, clinicians should maintain suspicion for thyrotoxicosis in transplant patients who present with neuropsychiatric or nonspecific systemic symptoms, especially when they have a history of amiodarone exposure.

Asset Subtitle

Brandon Calley

Meta Tag

Author List Brandon Calley, Laila Nomani, Nisar Asmi

Category Clinical Vignettes

Concept Amiodarone-Induced Thyrotoxicosis

Concept Thyrotoxicosis

Concept Urgent Thyroidectomy

Concept Heart Transplant Recipient

Concept Thyroid Testing

Distinguished Non-Finalist

Presenter Organization Medical College of Wisconsin

Presenting Author Brandon Calley

Track Adult

Keywords

amiodarone-induced thyrotoxicosis

heart transplant

thyrotoxicosis

thyroidectomy

delirium

hyperactive delirium

thyroid storm

amiodarone

cardiac denervation

neuropsychiatric symptoms

Amiodarone-Induced Thyrotoxicosis

Thyrotoxicosis

Urgent Thyroidectomy

Heart Transplant Recipient

Thyroid Testing