Spontaneous rhabdomyolysis as the presenting manifestation of undiagnosed Hashimoto’s thyroiditis: A case report

Hypothyroidism-induced rhabdomyolysis is a rare but life-threatening complication that often goes unrecognized. We report a 45-year-old male presenting with spontaneous severe rhabdomyolysis and acute kidney injury as the initial manifestation of undiagnosed Hashimoto’s thyroiditis, without identifiable precipitating factors. Laboratory findings revealed markedly elevated creatine kinase (45,800 U/L), severe myoglobinuria, acute renal impairment (creatinine 3.2 mg/dL), and profound hypothyroidism (thyroid-stimulating hormone [TSH] 98.5 mIU/L, FT4 0.3 ng/dL). Anti-thyroid peroxidase antibodies confirmed autoimmune thyroiditis (650 IU/mL). Despite 6 months of progressive symptoms, thyroid disease remained undiagnosed until this life-threatening presentation. Treatment with aggressive intravenous hydration, electrolyte management, and cautiously escalated levothyroxine therapy achieved complete muscle and renal recovery within 3 months. This case underscores the importance of thyroid screening in unexplained rhabdomyolysis and demonstrates excellent prognosis with appropriate management.