Malignant Hyperthermia Versus Thyroid Storm in a Patient With Symptomatic Graves Disease: A Case Report.

Malignant hyperthermia and thyroid storm are intraoperative emergencies with overlapping symptoms but different treatment protocols. We faced this diagnostic dilemma in a 25-year-old patient with symptomatic hyperthyroidism, elevated free T3 and free T4, and low thyroid-stimulating hormone from Graves disease despite treatment with propranolol 80 mg daily and methimazole 40 mg every 8 hours. During thyroidectomy, he developed hyperthermia and hypercarbia without tachycardia. When the rate of rise of PaCO2 and temperature accelerated, we treated the patient for malignant hyperthermia, a diagnosis subsequently confirmed by genetic testing.