A 28-year-old woman in Mumbai presents with fever, headache, myalgia, and neck stiffness for 3 days. CSF shows lymphocytic pleocytosis (120 cells/μL, 90% lymphocytes), normal glucose (55 mg/dL, serum 95 mg/dL), and elevated protein (65 mg/dL). Gram stain and bacterial culture are negative. PCR for enterovirus is pending. What is the most appropriate initial antiviral therapy?

## Management of Suspected Viral (Aseptic) Meningitis **Key Point:** In a young immunocompetent patient with classic viral meningitis CSF profile (lymphocytic pleocytosis, normal glucose, mildly elevated protein, negative Gram stain/culture) and **no features of encephalitis**, the most appropriate initial management is **supportive care** while awaiting confirmatory PCR results. ### CSF Profile Analysis **High-Yield:** The findings in this case are classic for viral (aseptic) meningitis: - Lymphocytic pleocytosis (90% lymphocytes, 120 cells/μL) - Normal glucose (CSF:serum ratio = 55/95 = 0.58, well above the 0.4 threshold for bacterial meningitis) - Mildly elevated protein (65 mg/dL) - Negative Gram stain and bacterial culture ### Why Supportive Care, Not Empirical Acyclovir? **Clinical Pearl:** The key distinction is **meningitis vs. encephalitis**: - This patient has **meningitis** (meningeal signs, normal mentation implied) — NOT encephalitis - Empirical acyclovir is mandated when **HSV encephalitis** is suspected (altered consciousness, focal neurological deficits, temporal lobe changes on MRI) - In **uncomplicated viral meningitis** without encephalitic features, enterovirus is the most common etiology (>85% of cases), and enteroviral meningitis is **self-limiting** with no specific antiviral therapy - Harrison's Principles (21e, Ch. 297) explicitly states: "Patients with viral meningitis who are not immunocompromised and have no features of encephalitis can be managed with supportive care" **Clinical Pearl:** Empirical acyclovir is indicated when: 1. Altered level of consciousness or confusion 2. Focal neurological deficits 3. Seizures 4. MRI showing temporal lobe involvement 5. Immunocompromised state None of these features are present in this case. ### Why Not Acyclovir Empirically? **Warning:** While acyclovir is safe, indiscriminate empirical use in all viral meningitis cases is NOT supported by current guidelines: - The stem describes **meningitis only** — no encephalitic features - HSV meningitis (Mollaret's meningitis) is typically benign and self-limiting even without acyclovir - Overuse of acyclovir contributes to nephrotoxicity risk and is not evidence-based in uncomplicated viral meningitis ### Why Not Ribavirin or Oseltamivir? **Warning:** - **Ribavirin**: Reserved for hemorrhagic fever viruses (Lassa, CCHF); no role in viral meningitis - **Oseltamivir**: Indicated for influenza; poor CSF penetration; not indicated empirically for viral meningitis ### Management Summary **High-Yield:** 1. Supportive care: analgesics, antipyretics, IV fluids, rest 2. Await enterovirus PCR (and HSV PCR if clinically indicated) 3. Monitor for development of encephalitic features — if they develop, initiate acyclovir 10 mg/kg IV q8h immediately 4. Most patients recover fully within 7–10 days [cite: Harrison 21e Ch. 297; Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 9e]