Myélopathies aiguës transverses : myélopathie inflammatoire ou ischémique ?

Abstract

The rapid development of paraparesis or tetraparesis combined with a bilateral sensory deficit that has a clearly defined rostral border and bladder dysfunction are the principal features of acute transverse myelopathy. Acute partial transverse myelopathy is far much more frequent: its symptoms are asymmetric, sometimes unilateral, and sensory deficit may predominate. An urgent MRI is required to exclude acute spinal cord compression. Diagnosis of ischemic acute transverse myelopathy includes the following elements: sudden onset, neurologic symptoms compatible with infarction in the anterior spinal artery area (by far the most frequent location for spinal cord infarction), and presence of a specific cause of spinal cord ischemia. In all other cases where it is difficult to distinguish spinal cord infarction from myelitis, analysis of the cerebrospinal fluid is essential. Most cases of inflammatory acute transverse myelopathy can be linked to a defined cause. Multiple sclerosis is a major cause of partial acute transverse myelopathy. MRI lesions are usually small, located in the lateral or posterior part of the spinal cord. Diagnostic elements include multiple lesions of multifocal demyelination on the cerebral MRI, oligoclonal bands in the cerebrospinal fluid, and the absence of clinical or laboratory abnormalities that suggest systemic disease. Neuromyelitis optica, also known as Devic's disease, has often been considered a variant form of multiple sclerosis. Recent immunologic studies confirm the hypothesis that it is a distinct entity. Infectious transverse acute myelitis is often of viral origin. It may result from direct viral stress but more frequently follows immunologically-mediated indirect stress. This acute parainfectious myelitis, like postvaccinal myelitis, may be considered as a spinal single-focus form of acute disseminated encephalomyelitis (ADEM). It is important to distinguish the latter from an initial episode of multiple sclerosis, because their prognosis and treatment differ.