ABSTRACT

Acute transverse myelitis (ATM) is a focal inflammatory disorder of the spinal cord resulting in motor, sensory, and autonomic dysfunction. It is a rare disorder with an estimated 1400 new cases diagnosed in the United States per year (between 1 and 8 per million per year). This leads to a total prevalence of approximately 34,000 people chronic sequlae of ATM; approximately 20% of these individuals had the acute illness before the age of 18 years. Idiopathic ATM must be distinguished from acute myelopathy secondary to a definable cause and from compressive myelopathies to insure appropriate management. Between 6% and 43% of patients with ATM will be diagnosed with multiple sclerosis (most with the benefit of longitudinal follow up), 8-16.5% may have an associated systemic mixed connective tissue disorder, and up to 5% may have features suggesting that the acute myelopathy is caused by direct infection of the spinal cord (i.e., mycoplasma or herpes virus family). Up to 14% of patients who present with an acute noncompressive myelopathy appear to have had a vascular cause (i.e., infarct or vascular malformation) (JHTMC case series). Ten to 45% patients with an acute myelopathy who have no clearly established etiology are classified as having idiopathic ATM.