Association of Rhabdomyolysis with Uncontrolled Autoimmune Thyroid Disease in Adolescents

Objective To illustrate the rare occurrence of rhabdomyolysis presenting in adolescents with autoimmune thyroid disease and to briefly review the literature regarding pathophysiology and treatment. Methods We present 3 children who developed rhabdomyolysis in the setting of concurrent thyroid disease: a 17-year-old female with undiagnosed hyperthyroidism, a 16-year-old female with undiagnosed hypothyroidism, and a 12-year-old female who had been treated for hypothyroidism for several years but was noncompliant. Each one presented with severe proximal muscle pain and weakness. They were afebrile and had no history of trauma. Results All 3 patients had dark urine (urinalysis was heme positive but had no red blood cells) and very high creatine kinase (CK) levels. They were treated with aggressive hydration since the most dangerous complication of rhabdomyolysis is acute renal failure. The urine cleared in a few days in all patients and CK normalized in a few months. Conclusion Even though rhabdomyolysis is a rare complication of autoimmune thyroid disease, physicians should be aware of its possibility. CK levels and urinalysis should be checked in any patient with thyroid disease who presents with muscle pain, weakness, and dark urine. Also, physicians should know that rhabdomyolysis can be the presenting feature of new-onset thyroid disease. The prognosis is excellent in pediatrics.