Chronic active herpes simplex type 2 encephalitis in an asymptomatic immunocompetent child

Area of Science:

• Neurology
• Infectious Diseases
• Pediatrics

Background:

• Herpes simplex virus type 2 (HSV-2) encephalitis typically presents acutely with severe neurological symptoms.
• Chronic or indolent forms of HSV encephalitis are less common and may present atypically.

Observation:

• A unique case of chronic, active, granulomatous HSV-2 encephalitis was identified in an 8-year-old immunocompetent female acquired neonatally.
• Extensive, bilateral cerebral parenchymal involvement was incidentally discovered via neuroimaging.
• The child remained asymptomatic with no neurological findings throughout the observation period.

Findings:

• Diagnosis was confirmed using serial neuroimaging, brain biopsy, and quantitative polymerase chain reaction (PCR) targeting the glycoprotein G gene for HSV-2 differentiation.
• The condition followed an indolent course over 5 years, with the patient exhibiting benign behavior.
• Treatment involved intermittent intravenous steroids and daily valacyclovir.

Implications:

• This previously undescribed form of HSV-2 encephalitis can be indolent, asymptomatic, and potentially underdiagnosed in children.
• Pediatricians should consider HSV-2 encephalitis in the differential diagnosis, especially in infants with maternal HSV-2 history.
• Early identification and management are crucial, even in asymptomatic cases, to prevent potential long-term complications.