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Certain clinical, imaging, and laboratory findings can help determine the etiology and prognosis in patients presenting with transverse myelitis, according to a new guideline from the American Academy of Neurology.

One such clinical feature is the distinction between acute complete transverse myelitis, characterized by spinal inflammation that results in severe or moderate symmetric loss of function below the level of the lesion, and acute partial transverse myelitis, with milder weakness and "asymmetric or dissociated sensory symptoms," according to Thomas F. Scott, MD, of Drexel University in Pittsburgh, and colleagues.

A review of the published literature has shown that patients with the partial form of myelitis have a higher rate of transition to multiple sclerosis (MS) over the subsequent five years, at 10.3% (95% CI 4.1 to 23.6), compared with a rate of 0% to 2% in those with complete myelitis, according to the guideline, which was published in the Dec. 13 issue of Neurology.

Partial myelitis is also associated with a higher rate of relapse (40% versus 10%) during the subsequent five years, Scott's group found.

The length of the spinal lesion seen on MRI can help identify the cause of the inflammation, particularly in distinguishing between MS and neuromyelitis optica.

For instance, in one study, 65% of patients with lesions involving three or more segments had neuromyelitis optica compared with 32% of those who had MS (P=0.001).

The presence of cerebral lesions on MRI, however, points to a diagnosis of MS, with an 80% conversion rate within three to five years.

Laboratory findings that can be useful include the presence of neuromyelitis optica immunoglobulin-G antibodies in patients with complete myelitis, because patients with spinal inflammation and these autoantibodies, which are also known as aquaporin-4-specific autoantibodies, often progress to neuromyelitis optica.

When it isn't clear whether the spinal symptoms are being caused by an inflammatory process or a spinal cord infarct, demographic factors can help distinguish between these conditions, the literature suggested.

For example, older patients had a greater risk for the myelitis being caused by an infarct, and women were more likely to have any inflammatory myelopathy (80%, 95% CI 0.51 to 0.77) or MS specifically (68%, 95% CI 0.51 to 0.81).

The guideline also summarized the sparse data on treatment for transverse myelitis.

Despite the lack of evidence in the literature, high-dose steroids are often the initial treatment, with intravenous methylprednisolone being given in doses of 1 g per day for three to seven days.

For patients who fail to respond to the steroid, the guideline noted that plasmapheresis is "possibly effective."

Other treatments that have been tried include the B-cell depleting agent rituximab (Rituxan), which seemed to decrease the relapse rate in two small studies, and mitoxantrone (Novantrone), for which insufficient evidence for efficacy could be found.

There also was insufficient evidence for the use of other immunosuppressants such as azathioprine and cyclophosphamide (Cytoxan) for treating the acute attack or promoting recovery.

Finally, the guideline called for future research to further delineate clinical, imaging, and laboratory findings that can aid in diagnosis, and to prospectively examine treatments for the acute attack and for preventing relapse.

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