Alternative Diagnoses in Idiopathic Transverse Myelitis

Idiopathic transverse myelitis (ITM) is defined as an inflammatory myelopathy of undetermined etiology that peaks clinically between 4 hours and 21 days after onset, with clear myelopathic signs on exam and MRI and no etiology after a thorough work-up.

Neurologists at the Mayo Clinic reviewed records from 226 patients seen or referred with a presumptive diagnosis of ITM. After evaluation, only 18% had confirmation of ITM. A myelopathic etiology was determined in 70%; 12% did not have myelopathy confirmed (9% nonneurologic/functional, almost 4% neurologic but not myelopathic).

Inflammatory myelopathies were diagnosed in 46% of referrals: multiple sclerosis in 33%, neurosarcoidosis in 5%, neuromyelitis optica spectrum disorder (NMOSD) in 5%, my…