General description

Neonatal herpes simplex encephalitis differs significantly from herpes simplex encephalitis in children and adults in both clinical presentation and imaging findings. More than 80% of cases result from exposure to the herpes simplex virus (HSV) during vaginal delivery. Both HSV type 1 and type 2 can cause the infection. Neonatal herpes simplex infection is classified into three forms: disseminated, central nervous system (CNS), and localized (limited to the skin, eyes, or mouth). Neonatal herpes simplex encephalitis is most commonly seen in the disseminated and CNS forms.

The CNS form typically manifests clinical symptoms around the third week after birth, later than the disseminated form. Symptoms are often nonspecific, including seizures and poor feeding. The disseminated form is the most frequent and usually appears within 7 to 10 days after birth. It begins with fever, reduced activity and feeding ability, skin and oral lesions, and may progress to hepatosplenomegaly, jaundice, and respiratory distress. Skin lesions such as blisters or scars occur in about half of all cases, regardless of the form.

Diagnosis is confirmed through viral culture or HSV gene identification using PCR. In cases of CNS involvement, cerebrospinal fluid analysis reveals increased cell counts and protein concentration, along with abnormalities on brain MRI. Treatment involves high-dose intravenous acyclovir, though mortality and neurological complications remain high.