How should I treat a patient who presents with a painful vesicular dermatomal rash (shingles) and new‑onset encephalopathy (altered mental status, seizures, or focal neurologic deficits)?

Management of Shingles with Encephalopathy

Immediately initiate high-dose intravenous acyclovir for any patient presenting with a dermatomal vesicular rash (shingles) and new-onset encephalopathy, as VZV reactivation can cause life-threatening encephalitis, particularly in elderly and immunocompromised patients. 1

Immediate Treatment Protocol

• Start IV acyclovir immediately without waiting for confirmatory testing when shingles and encephalopathy coexist, as VZV encephalitis requires urgent antiviral therapy to reduce morbidity and mortality 1, 2
• The standard dosing is high-dose IV acyclovir (typically 10 mg/kg every 8 hours, adjusted for renal function), not oral formulations, as immunocompromised patients and those with CNS involvement require intravenous therapy 1, 3
• Continue IV acyclovir for a minimum of 7-10 days, or longer until clinical improvement is documented, as premature discontinuation can lead to treatment failure 3, 4

Critical Diagnostic Workup

• Perform lumbar puncture as soon as possible unless contraindications exist (signs of increased intracranial pressure or brain shift requiring CT first) 1
• Obtain CT scan before LP if the patient has focal neurologic deficits, papilledema, or significantly altered consciousness suggesting mass effect 1
• Send CSF for VZV PCR and anti-VZV IgG/IgM antibodies, as CSF VZV IgG antibody detection is superior to VZV DNA PCR for diagnosing VZV vasculopathy and encephalitis 2, 4
• Order brain MRI to evaluate for characteristic findings: leptomeningeal enhancement, intramedullary lesions, or evidence of vasculopathy 5, 4
• Obtain EEG to rule out non-convulsive status epilepticus, which occurs in up to 8% of comatose patients and requires specific treatment 1

Key Clinical Recognition Points

• VZV encephalitis can occur with or without the characteristic dermatomal rash, and the absence of rash should not delay treatment if clinical suspicion is high 1, 4
• Elderly patients and those with cranial dermatome involvement (especially ophthalmic or Ramsay Hunt syndrome) are at significantly increased risk for CNS complications 1
• The presentation may be acute or insidious, with fever, headache, altered consciousness, ataxia, seizures, or focal neurologic deficits 1
• VZV can cause vasculopathy leading to stroke syndromes, which may present days to months after the rash resolves 1, 2

Special Considerations for Immunocompromised Patients

• Immunosuppressed patients (including those on steroids, tacrolimus, or with HIV) require immediate IV acyclovir and consideration of temporarily discontinuing immunosuppressive therapy 3, 5
• These patients may develop more severe disease with prolonged viral shedding, disseminated infection, and higher mortality despite treatment 1, 5
• Monitor closely for visceral involvement including pneumonia, hepatitis, and hemorrhagic complications 6, 5

Critical Pitfalls to Avoid

• Do not use oral antivirals (acyclovir, valacyclovir, famciclovir) for patients with encephalopathy, as these are reserved only for uncomplicated dermatomal zoster in immunocompetent patients 1, 3
• Do not discontinue acyclovir prematurely once HSV PCR returns negative, as VZV encephalitis requires the full treatment course 4
• Monitor renal function closely during IV acyclovir therapy, as acyclovir neurotoxicity can mimic or worsen encephalopathy, particularly in patients with acute kidney injury 7
• Do not assume the encephalopathy is solely due to sepsis or metabolic causes without excluding VZV CNS infection, as delayed treatment significantly increases morbidity 1

Adjunctive Management

• Manage seizures aggressively with antiepileptic medications if present, as seizures are common in VZV encephalitis 1
• Consider corticosteroids only in specific contexts (such as acute disseminated encephalomyelitis or severe vasculitis), but not routinely for VZV encephalitis 1
• Provide supportive care including pain management, as radicular pain often precedes or accompanies the neurologic symptoms 6, 2

Monitoring and Follow-up

• Reassess clinical status daily and obtain repeat neuroimaging if neurologic deterioration occurs, as VZV vasculopathy can cause progressive strokes 5, 2
• Continue treatment until complete resolution of encephalopathy and documented clinical improvement, which may require longer than the standard 7-10 day course 3, 5
• Monitor for postherpetic neuralgia and other chronic complications after acute treatment, as these are common sequelae requiring long-term management 6, 2