Herpes simplex encephalitis is the most common cause of sporadic encephalitis in the western world. Natalizumab is licensed for relapsing remitting multiple sclerosis in patients with high disease activity despite treatment with interferon-beta and patients with rapidly evolving severe, multiple sclerosis. Biopsies of the brain in five patients revealed H. False-positive CSF HSV PCR results are rare when testing is performed in experienced laboratories. There is a great need for a noninvasive test that is positive early in the disease. This case adds support to the suggestion that natalizumab also increases the reactivation risk of CNS herpes simplex infection. Idoxuridine appears to be effective therapy for this devastating form of encephalitis.
Quantitative PCR testing provides information about HSV viral load in CSF, but the potential correlation of viral load with prognosis or other clinical features of disease remains uncertain. It is essential to treat early; patients who are young and have not reached coma or impaired consciousness may show 65% recovery and return to normal function. The patient made an eventual excellent recovery following 21 days of intravenous acyclovir therapy followed by 14 days of oral treatment. Aided by a training grant (AI 00261) and a research grant (AI 05721) from the National Institute of Allergy and Infectious Diseases, and another grant from the Detroit General Hospital Research Corporation.