A 33-year-old male with no significant medical history presented to the emergency department (ED) with palpitations and tremors of the extremities. He stated that the symptoms had been present for at least 6 months and had worsened over the past month. He did not seek care previously because he had no health insurance. He also reported associated diarrhea after each meal, a 15-lb unintentional weight loss, insomnia, and fatigue. He denied fever, chest pain, dyspnea, orthopnea, abdominal pain, dysphagia or recent viral illness. His mother, who accompanied him, described increased emotional lability, poor attention span, and occasional memory loss. The patient denied taking any medication or previous surgeries. He smoked half a pack of cigarettes per day (5 pack years) and denied alcohol or drug use.

Physical examination results were as follows: BP, 141/77 mm Hg; heart rate, 155 beats per minute and regular; respirations, 18 breaths per minute; temperature, 99.1°F; oxygen saturation, 97% on room air. The patient spoke rapidly and appeared anxious. He was alert and oriented × 3. The skin was warm and smooth. Pupils were approximately 9 mm in size and equal, with exophthalmus, periorbital edema, and lid lag (Figure 1). The thyroid was nontender and diffusely enlarged. Lungs were clear, and auscultation demonstrated irregularly irregular tachycardia with hyperdynamic apical impulse. The abdomen was soft and nontender. The lower extremities revealed pretibial myxedema bilaterally. With slight movement of the extremities significant tremor was noted, and the patient was hyperreflexic +4/4. The motor strength examination revealed easy fatigability and generalized weakness.

Results of a CBC and comprehensive metabolic panel were unremarkable. Tests for creatine kinase MB subunit and troponin were negative as well. Thyrotropin (TSH) was less than 0.010 mIU/L; thyroxine (T4) was greater than 24.0 ng/dL. The chest film was normal. An ECG demonstrated atrial fibrillation with rapid ventricular response (RVR) of 172 beats per minute.

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This article originally appeared on JAAPA