We report a case of a woman with transverse myelitis and McArdle disease and discuss diagnostic challenges.

Idiopathic transverse myelitis is a rare inflammatory spinal cord disorder that can present with weakness, numbness, or autonomic dysfunction. McArdle disease, an autosomal recessive disorder caused by muscle phosphorylase deficiency, results in lifelong exercise intolerance, exertional rhabdomyolysis, muscle contractures, and a second-wind phenomenon.

We reviewed the clinic records of a woman who presented with recurrent rhabdomyolysis following transverse myelitis.

A 44-year-old woman contracted a presumed gastroenteritis and developed ascending numbness a week later. She had an unremarkable serum lab and spinal fluid evaluation and normal MRI brain. However, MRI of the spine showed an enhancing T7 lesion and a nonenhancing C5-C6 lesion. She was diagnosed with idiopathic transverse myelitis. At a follow-up visit, she remained relapse-free with an EDSS of 2 without a disease modifying treatment.

Several months following this episode, she was hospitalized on 2 separate occasions for severe back pain following exertion. CK was elevated during both admissions (26,000 and 40,000). A muscle biopsy of her right thigh showed absent myophosphorylase and increased glycogen stores, consistent with McArdle disease. Upon further questioning, the patient disclosed life-long exercise intolerance, contractures, and improved exercise capacity after rest. She believed that the warning signs of impending muscle contracture were concealed by the truncal numbness related to transverse myelitis.

McArdle disease in a patient with comorbid transverse myelitis is rare. Fatigue, weakness, and pain are common issues in both disorders. The two pathologies appeared to occur independently in the patient, but the truncal numbness from transverse myelitis might have masked the myopathic pain and contributed to later hospitalizations for rhabdomyolysis.