Fulminant course in a case of diffuse myelinoclastic encephalitis - A casereport

We report on a 10-year old previously healthy boy who exhibited a fulminant and nearly monophasic clinical course of demyelinating encephalitis with r elapsing intracranial hypertension syndrome. Histologic examination of a di agnostic brain biopsy revealed an inflammatory demyelinating process with p erivascular T lymphocytic infiltration and axonal damage reminiscent of mul tiple sclerosis-like lesions. In the brain, the DNA of human Herpes virus 6 (HHV6) was detectable. Eleven months after the initial symptoms and on mai ntainance with oral steroids, MRI showed demyelination of both hemispheres as well as demyelination of the brain stem and Wallerian degeneration. The boy exhibited a severe neurologic defect syndrome. The clinical and radiolo gical course is unusual because of the asymmetric progression of the enceph alitis and the extensive confluent lesions without demarcated border or enh ancement of the rim after injection of gadolinium. The clinical course show ed no definite steroid response. The pathogenetic relevance of HHV6 remains elusive. Although single patients with HHV6-associated encephalomyelitis h ave been reported, HHV6 DNA is occasionally detected in brains of healthy i ndividuals.