Acute myelopathy of unknown aetiology: a follow-up investigation.

Acute myelopathy refers to acute or subacute spinal cord dysfunction secondary to various causes. Recent studies suggest a number of distinct clinical, laboratory, MRI and outcome profiles for the various aetiologies. Nevertheless, the aetiology of acute myelopathy remains unknown in up to 60% of the patients. The probability of establishing the correct diagnosis increases with the duration of clinical and MRI follow-up. This paper presents the results of a follow-up of nine cases of acute myelopathy of unknown aetiology. One patient was lost during follow-up. Mean age of patients at the time of the follow-up interview was 48 years (+/-12). Average time from discharge to follow-up interview was 3.6 (+/-0.5) years. In four patients (mean age 45+/-13 years) the origin of acute myelopathy remained unclear after an average follow-up of 3.3 years. In one patient the diagnosis of multiple sclerosis was established during follow-up. In another patient the clinical course was suggestive for multiple sclerosis. One patient was diagnosed with systemic collagen vascular disease and in one patient a diagnosis of non-Hodgkin's lymphoma was established. It is unclear whether the patients in whom the aetiology of acute myelopathy remained unknown, even after several years of follow-up, are at a higher risk of developing progressive disease. Larger studies with longer follow-up periods and clear clinical, laboratory and MRI criteria should help to shed some light on this issue.