Human Herpesvirus-6 may be Neurologically Injurious in Some Immunocompetent Children.

PURPOSE: Human herpesvirus 6 (HHV-6) can infect the central nervous system in immunocompromised individuals. Less is known, however, about HHV-6 infection in immunocompetent patients. This study evaluated the neurologic features and prognosis of HHV-6 infection in immunocompetent patients.

METHODS

The medical records of patients aged 1 month to 18 years who underwent cerebrospinal fluid examinations and were tested for 6 viruses, including HHV-6, by multiplex polymerase chain reaction were evaluated retrospectively.

RESULTS

During the study period, 252 children were included. None had underlying disease and all were immunocompetent. Their mean age at diagnosis was 40.98 ± 47.65 months. Of these 252 patients, 144 (57.1%) were diagnosed with meningitis, 84 (33.3%) with febrile seizure not induced by meningitis, and 24 (9.5%) with encephalitis. Of the 9 patients positive for HHV-6, 3 (33.3%) had encephalitis, 3 (33.3%) had meningitis, 1 (11.1%) had complex febrile seizure, and the other 2 patients had fever alone. Outcomes were worse in the seizure group (Fisher exact test, P = .048), especially in patients with status epilepticus (Fisher exact test, P = .012), than in the other groups. Encephalitis patients with and without HHV-6 differed significantly in age (24.0 ± 10.8 vs 63.4 ± 47.7 months, t-test P < .05), with status epilepticus being more frequent in those with HHV-6 (Fisher exact test, P = .010). All 3 encephalitis patients positive for HHV-6 had neurologic sequelae; 2 who had mild sequelae were treated with antiviral agents and intravenous immunoglobulin.

CONCLUSIONS

HHV-6 may not be completely benign in immunocompetent children. It can be associated with encephalitis and poor prognosis.