Abstract
A 50 yearold man developed ascending necrotizing myelitis without any associated disease. After admission due to gait distrubance, the symptoms progressed rapidly and quickly. Neurological disturbance had progressed to an incomplete paraplesia below C 4 level; incontinence and drowsiness developed. Herpes Simplex viral myelitis was suspected through virological tests, which showed higher specific HSV antibody values of HSV-1 IgG of 640-fold in serum. Myelin basic protein (MBP) in the cerebrospinal fluid (CSF) registered 24.3 ng/ml. When he was treated with Acyclovir for 17 days, his general and neurological status improved significantly. Virological examinations showed 50-fold HSV-1 IgG in serum, and MBP in the CSF was 3.3 ng/ml. The MBP measurement and virolgical tests of the CSF and serum prove extremely important in diagnosing an ascending myelitis of unknown cause. (J Nippon Med Sch 1997; 64: 566-568)