BACKGROUND: Muscular symptoms, including stiffness, myalgia, cramps, and fatigue, are present in the majority of the patients with symptomatic hypothyroidism, but rhabdomyolysis, the rapid breakdown of skeletal muscle, is a rare manifestation. In most patients with hypothyroidism who develop rhabdomyolysis, precipitating factors, such as strenuous exercise or use of lipid-lowering drugs, can be identified.

CASE REPORT: We report a case of a 52-year-old Hispanic woman with a history of hypothyroidism, hypertension, and type 2 diabetes mellitus who presented with fatigue, severe generalized weakness, bilateral leg pain, and recurrent falls. She reported poor medication compliance for the preceding month. Initial laboratory testing showed elevated thyroid stimulating hormone (TSH) and creatine kinase (CK) levels, indicating uncontrolled hypothyroidism with associated rhabdomyolysis. Supportive treatment with intravenous fluids and intravenous levothyroxine were initiated and resulted in dramatic clinical improvement.

CONCLUSIONS: We report a case of rhabdomyolysis, which is a rare but potentially serious complication of hypothyroidism. Screening for hypothyroidism in patients with elevated muscle enzymes should be considered, since an early diagnosis and prompt treatment of hypothyroidism is essential to prevent rhabdomyolysis and its consequences.

Keywords: Hypocalcemia, Hypokalemia, Hypothyroidism, Methadone, rhabdomyolysis, Trimethoprim-Sulfamethoxazole Combination