What is the treatment for Central Nervous System (CNS) shingles infection?

Treatment of CNS Shingles Infection

For CNS shingles infection (VZV encephalitis or meningitis), initiate intravenous acyclovir 10 mg/kg every 8 hours immediately for 14-21 days in adults with normal renal function, with immunocompromised patients requiring at least 21 days of treatment. 1

Immediate Diagnostic Confirmation

• Obtain CSF PCR for VZV to confirm diagnosis, as it has high sensitivity and specificity 2, 1
• CSF analysis typically shows lymphocytic pleocytosis, mildly elevated protein, and normal glucose 2
• Distinguish between VZV meningitis and encephalitis immediately, as encephalitis carries higher neurologic morbidity and mortality risk and may require the full 21-day treatment course 2, 1
• Perform MRI as soon as possible in all patients with suspected CNS involvement 2

Treatment Protocol by Patient Population

Immunocompetent Adults

• Intravenous acyclovir 10 mg/kg every 8 hours for 14-21 days 1, 3
• Treatment duration of 14 days may suffice for uncomplicated meningitis, but extend to 21 days for encephalitis or severe presentations 2, 1
• Initiate treatment immediately upon clinical suspicion—do not wait for confirmatory PCR results, as earlier treatment correlates with better outcomes 1, 3

Immunocompromised Patients

• Intravenous acyclovir 10 mg/kg every 8 hours for at least 21 days 2
• Consider longer treatment courses as viral clearance is more difficult in this population 2
• Obtain repeat CSF PCR at end of therapy to confirm viral clearance; if positive, continue antiviral therapy 2, 3
• Consider long-term oral suppressive therapy until CD4 count >200×10⁶/L (or CD4% >15% if <5 years old) in HIV-infected patients 2

Pediatric Patients

• Intravenous acyclovir 500 mg/m² (or 10 mg/kg) every 8 hours for at least 10 days 2
• Immunocompromised children require longer treatment duration, similar to adults 2

Neonates

• Higher-dose acyclovir 20 mg/kg intravenously every 8 hours for 21 days 1, 3

Management of Increased Intracranial Pressure

• If CSF opening pressure ≥25 cm H₂O with symptoms of increased intracranial pressure, perform therapeutic CSF drainage via lumbar puncture 1
• For persistent pressure elevation, repeat lumbar puncture daily until pressure and symptoms stabilize 1
• Consider temporary percutaneous lumbar drain or ventriculostomy for patients requiring repeated daily lumbar punctures 1

Monitoring During Treatment

• Monitor renal function throughout treatment, as acyclovir causes nephrotoxicity; adjust doses in renal impairment 1, 3
• Obtain repeat CSF PCR at end of therapy in patients without appropriate clinical response 1, 3
• If PCR remains positive for VZV after completing treatment course, continue antiviral therapy 1, 3

Alternative Therapy for Acyclovir Resistance or Allergy

• Foscarnet 40 mg/kg intravenously every 8 hours for patients with documented acyclovir resistance or severe allergy 1, 4
• Acyclovir resistance is rare in immunocompetent hosts but more common in severely immunocompromised patients with prolonged antiviral exposure 4

Special Populations

Pregnant or Lactating Patients

• Treat identically to non-pregnant patients with same disease manifestation 2, 1
• Avoid doxycycline (not relevant for VZV CNS infection, but important if considering alternative diagnoses) 2

HIV-Infected Patients

• Higher risk for severe or prolonged disease course 1
• Broader diagnostic workup required, including CSF PCR for HSV 1 & 2, EBV, CMV, and enteroviruses 2

Critical Pitfalls to Avoid

• Do not delay treatment waiting for confirmatory testing—initiate acyclovir immediately based on clinical suspicion, as early treatment (within 4 days of symptom onset) significantly improves outcomes 1, 3
• Do not use standard 7-10 day courses used for uncomplicated shingles; CNS involvement requires minimum 14-21 days 2, 1
• Do not confuse with HSV encephalitis, which has similar presentation but different epidemiology; obtain PCR for both HSV and VZV if diagnosis uncertain 2
• Do not use oral acyclovir for CNS disease—intravenous administration is mandatory for adequate CNS penetration 1, 3
• Do not assume treatment prevents post-herpetic neuralgia—acyclovir does not protect against this complication even with appropriate CNS treatment 5, 6
• Relapse can occur after completion of therapy, requiring vigilant follow-up for at least 3-6 months 1, 3

Post-Treatment Follow-Up

• Monitor clinically after completion of therapy for potential neurological sequelae 1
• Residual contrast enhancement on brain imaging may persist for 3-6 months; do not prolong antimicrobial treatment based solely on radiological findings 7
• Consider suppressive oral antiviral therapy in severely immunocompromised patients to prevent recurrence 2