Patients are most often male, usually children or young adults.
Clinical presentation is characterized by the abrupt onset of fever and headache, followed by a rapid progression to stupor or coma. The CSF pressure is typically elevated and analysis reveals numerous neutrophils. Patients usually die within one to six days. Gross examination reveals a diffusely swollen and soft brain. Indeed, numerous attempts to identify an infectious agent in cases of acute hemorrhagic leukoencephalopathy have met with failure.