The term “transverse myelitis” describes a heterogeneous group of inflammatory disorders that are characterized by acute or subacute motor, sensory, and autonomic (bladder, bowel, and sexual) spinal cord dysfunction. The clinical signs are caused by an interruption in ascending and descending neuroanatomical pathways in the transverse plane of the spinal cord, and a resulting sensory level is characteristic of the syndrome.

Diagnostic Criteria for Transverse Myelitis*

• Bilateral (not necessarily symmetric) sensorimotor and autonomic spinal cord dysfunction
• Clearly defined sensory level
• Progression to nadir of clinical deficits between 4 hours and 21 days after symptom onset
• Demonstration of spinal cord inflammation: cerebrospinal fluid pleocytosis or elevated IgG index,† or MRI revealing a gadolinium-enhancing cord lesion
• Exclusion of compressive, postradiation, neoplastic, and vascular causes

* Clinical events that are consistent with transverse myelitis but that are not associated with cerebrospinal fluid abnormalities or abnormalities detected on MRI and that have no identifiable underlying cause are categorized as possible idiopathic transverse myelitis.
† The IgG index is a measure of intrathecal synthesis of immunoglobulin and is calculated with the use of the following formula: (CSF IgG ÷ serum IgG) ÷ (CSF albumin ÷ serum albumin), where CSF denotes cerebrospinal fluid.

References:

1. Frohman E, Wingerchuk D. Transverse Myelitis. N Engl J Med 2010;363:564-72. [Medline]
2. Transverse Myelitis Consortium Working Group. Proposed diagnostic criteria and nosology of acute transverse myelitis. Neurology. 2002 Aug 27;59(4):499-505. [Medline]