A 28-year-old woman presents to the emergency department with severe bilateral lower abdominal pain, fever (38.5°C), and vaginal discharge for 3 days. On examination, she has cervical tenderness and vesicular lesions on the vulva and perianal region. Gram stain of cervical discharge shows no organisms. PCR for HSV-1 and HSV-2 from the vesicular fluid is positive. She reports this is her first episode of genital herpes. Which of the following best explains the neurological complication she is at highest risk for during this acute infection?

Explanation

## Clinical Presentation & Diagnosis **Key Point:** Primary HSV-2 genital infection carries a 10–15% risk of CNS involvement, most commonly aseptic meningitis during the acute phase. The patient's presentation of primary genital herpes (vesicular lesions, cervical tenderness, positive HSV PCR) with systemic symptoms (fever, malaise) places her at risk for disseminated disease including meningitis. ## HSV Neurological Complications: Spectrum & Frequency | Complication | Frequency in Primary Infection | CSF Finding | Typical Presentation | |---|---|---|---| | Aseptic meningitis | 10–15% (HSV-2 > HSV-1) | Lymphocytic pleocytosis, normal glucose | Fever, headache, neck stiffness during acute genital infection | | Encephalitis | <1% | Pleocytosis, RBCs, low glucose | Altered mental status, seizures, focal deficits | | Sacral radiculomyelitis | 2–3% (HSV-2) | Pleocytosis | Sacral pain, urinary retention, leg weakness | | Guillain-Barré | Rare | Normal or mild pleocytosis | Post-infection (2–4 weeks), ascending paralysis | **High-Yield:** HSV-2 meningitis is the most common viral meningitis in immunocompetent women of childbearing age. It occurs during the acute phase of primary infection and is self-limited, resolving in 3–7 days without antiviral therapy (though acyclovir shortens duration). ## Pathophysiology **Clinical Pearl:** Aseptic meningitis in primary HSV-2 infection results from viral dissemination via retrograde axonal transport along sacral nerve roots to the lumbosacral dorsal root ganglia, with subsequent inflammation of the meninges. CSF shows: - Lymphocytic pleocytosis (typically 100–1000 cells/μL) - Normal or mildly elevated protein - Normal glucose (unlike bacterial meningitis) - Positive HSV PCR (gold standard for diagnosis) ## Why Aseptic Meningitis Is the Correct Answer 1. **Timing & frequency:** Most common CNS complication in primary HSV-2 infection (10–15% incidence) 2. **Presentation match:** Occurs during acute genital infection with fever and systemic symptoms 3. **CSF profile:** Lymphocytic pleocytosis is pathognomonic for viral meningitis 4. **Prognosis:** Self-limited and responsive to acyclovir; no permanent sequelae **Mnemonic: "HASTE"** — HSV Aseptic meningitis in primary Sexually Transmitted infection, Early in course, Transient resolution ## Management Implications Lumbar puncture with CSF HSV PCR is indicated if meningitis is suspected. IV acyclovir 10 mg/kg every 8 hours is recommended, though meningitis alone (without encephalitis) may resolve spontaneously.