Abstract 1029 Poster Session IV, Tuesday, 5/4 (poster 168)

Background: Human herpesviruses types 6 and 7 (HHV-6 and HHV-7) are closely related lymphotropic dsDNA viruses with known neurotropic properties. Recent attention has focused on what role, if any, they play in the pathogenesis of febrile convulsions in young children. If they do have a role, then one might expect to detect them in the cerebrospinal fluid (CSF) of affected patients.

Objective: To describe the frequency with which HHV-6 and HHV-7 are found in the CSF of patients with febrile convulsions and of matched control patients.

Methods: CSF samples were prospectively collected from a case series of patients with febrile convulsions and from control patients without febrile convulsions matched for age, sex, and race. All cases were evaluated in the emergency department (ED) of an urban, tertiary care, pediatric medical center. Inclusion criteria for cases included a convulsion attributed solely to fever, age 6 months to 6 years, temperature ≥38.0°C, and the availability of CSF. Exclusion criteria included a CSF pleocytosis, an underlying seizure disorder, or any other chronic neurologic condition. Using the polymerase chain reaction (PCR), the CSF samples were examined for the presence of viral DNA from HHV-6, HHV-7, Herpes Simplex Viruses Types 1 and 2 (HSV-1 and HSV-2), and Cytomegalovirus (CMV). CSF samples from a subset of both groups were also examined for RNA from enteroviruses.

Results: Over the seven-and-a-half month collection period, a total of 174 patients were evaluated in the ED for fever and seizures. Of these, 23 (13.2%) met study criteria. Their mean age was 1.4±0.7 years. Sixteen of the 23 (70%) were male. These patients were matched to 21 controls. None of the CSF samples from the cases or controls had PCR evidence of HHV-6, HHV-7, HSV-1, or HSV-2. All of the cases were negative for CMV (95%CI for each virus for cases 0,13%). One control subject was positive for CMV (a febrile 15 month male who was neurodevelopmentally normal at 6 months follow-up). The ten cases and 7 controls tested for enteroviral RNA were negative.

Conclusions: Neither HHV-6 nor HHV-7 appear to be present in the CSF from patients with febrile convulsions or from matched controls. What role, if any, these viruses have in the pathogenesis of febrile convulsions merits further study.