Neonatal herpes encephalitis: a case series and review of clinical presentation

To describe the clinical and laboratory findings in cases of neonatal herpes simplex virus (HSV) encephalitis.

Neonatal HSV encephalitis is a devastating infection which requires a high degree of clinical suspicion and rapid initiation of antiviral therapy.

We performed a retrospective search for all cases of HSV encephalitis within the two Saskatchewan pediatric tertiary care centers for the period of 1985-2001. Only those patients with consistent clinical presentations along with direct evidence of presence of HSV, such as positive cerebrospinal fluid (CSF) viral cultures, positive polymerase chain reaction (PCR) for HSV from CSF, or positive immunoglobulin G against HSV from neonatal blood, were selected.

Five male and four female infant patients were identified. At a mean age of presentation of 24 +/- 20 days, seizures occurred in six neonates, lethargy in six neonates, temperature changes in five neonates, and apnea in three neonates. Examination of CSF demonstrated an initial monocytosis or lymphocytosis, elevated CSF protein and depressed CSF glucose in 100% of patients. Electroencephalography (EEG) was abnormal in 100% of patients. Initial computerized tomography was abnormal in 55% of patients. Clinical follow-up over an average of two years demonstrated developmental delay in four patients and upper motor neuron findings in four patients. No patients suffered from postencephalitic epilepsy or mortality.

Neonatal HSV encephalitis most commonly presents with seizures, lethargy, and dysthermia. Cerebrospinal fluid testing and EEG have 100% sensitivity in cases with laboratory confirmation of HSV presence. Improvements in morbidity and mortality as compared to previous reports may relate to better recognition of this illness and acyclovir therapy. The lack of postinfection epilepsy in our series may also relate to better recognition and acyclovir therapy within this series of patients.