Atrial Fibrillation as an Initial Presentation of Apathetic Thyroid Storm

Atrial fibrillation as an initial presenting symptom of an apathetic thyroid storm is under-reported, especially in the setting of undiagnosed hyperthyroidism. Very rarely, thyroid storm can present with apathetic symptoms. The author presents a case of apathetic thyrotoxicosis with atrial fibrillation. The patient had a generalized weakness, lethargy, and weight loss as initial symptoms and was found to have atrial fibrillation, which was initially thought to be the inciting event. However, further evaluation revealed a new diagnosis of apathetic thyroid storm secondary to uncontrolled Graves' disease. She was managed medically for thyroid storm with hopes to control the tachyarrhythmia by controlling the underlying etiology. Subsequently, her symptoms resolved, and she came back to baseline except for continued atrial fibrillation, which was rate controlled. Early recognition of an apathetic thyroid storm can prevent mortality and morbidity as it can often be missed due to atypical symptoms.