Thyrotoxicosis factitia: a rare cause of junctional rhythm and cardiac arrest

Abstract

Introduction: Little is known about the types of arrhythmias due to exogenous thyroxine. We present an unusual set of cardiac arrhythmias in a fairly healthy athlete who succumbed to the severe complication of exogenous thyroxine. Case Description: A 50-year-old female athlete was brought into the emergency department (ED) in after a witnessed car accident. She was pulseless so was intubated and resuscitated in the field. In the ER the patient was found to be in a junctional rhythm with diffuse ST depressions. Initial blood workup was unremarkable. Drug screen was also negative. ABGs were showed respiratory acidosis. The only medication the patient was taking was thyroxine for her hypothyroidism. he was known by family to be abusing it for weight loss purposes. Her serum thyroxine (T4) levels turned out to be elevated (365ng) and TSH was less than 0.02. Decision-making: The patient went into cardiac arrest again and was persistently in the junctional rhythm.(Figure 1) This eventually lead her into severe bradycardia and cardiogenic shock. She was resuscitated again twice. However, by this point, the patient had pinpoint pupils and brain imaging consistent with anoxic brain injury. Conclusion(s): Thyroxine induced cardiac arrhythmias can range from sinus tachycardia to ventricular fibrillation, and surprisingly it can cause junctional rhythm due to an unknown mechanism. These arrhythmias can be fatal, underscoring the importance of discouraging thyroid hormone misuse.