Objective: To determine the long-term risk of developing clinically definite multiple sclerosis (CDMS) in patients with acute partial transverse myelitis (APTM) and normal cerebral magnetic resonance imaging (MRI) scans.
Methods: We retrospectively studied 30 consecutive patients with clinical evidence of APTM. Patients with symmetric severe acute transverse myelitis were considered to have complete transverse myelitis and were excluded. All patients underwent spinal and cerebral MRIs, 13 underwent cerebrospinal fluid analysis and 11 patients underwent evoked potential studies. Various other studies were performed to assess for connective tissue disease and causes of APTM other than demyelinating disease.
Results: After an average follow-up of 61 months, all laboratory and clinical evidence, including relapse history, indicated that three patients developed lesions on cerebral MRI and could be classified as CDMS by either Poser criteria (two patients) or MacDonald criteria (one patient). Relapses limited to the spinal cord seen clinically were seen in 14/30 (46.6%) patients. Oligoclonal bands were seen in 8/13 (62%) patients; one patient transitioned to CDMS. Unifocal lesions of the cord were seen in 19/30 (63%) patients, multifocal lesions were seen in 8/30 (27%) and 3/30 (10%) had negative MRIs. The three patients who converted to CDMS did so within five years of the onset of myelitis.
Conclusion: APTM with normal cerebral MRI had a low rate of conversion to CDMS in this long-term study. To date, there have been only a few follow-up studies that have addressed this issue.