Herpes zoster–associated meningitis risk
Shingles (herpes zoster) can rarely be complicated by central nervous system infection, including encephalitis, meningitis, or meningoencephalitis. [1] Severe headache with meningeal or neurologic red-flag features during an active zoster outbreak warrants urgent evaluation for meningitis and other CNS complications. [2]
Clinical features that raise concern for meningitis
Meningitis should be suspected when fever and headache occur together with neck stiffness and altered level of consciousness or cognition. [2] VZV CNS infection can present with acute headache and meningitis features such as nuchal rigidity and photophobia. [3] Electric shock–type head pain can occur in neurologic syndromes and warrants urgent assessment when accompanied by zoster near the head or neck and severe headache. [2]
Herpes zoster complications affecting the CNS
CDC lists encephalitis as a shingles complication. [1] CDC also describes rare neurologic complications of zoster, including meningoencephalitis. [4]
Diagnostic evaluation for suspected meningitis
Urgent emergency evaluation is recommended when meningitis red flags are present because cerebrospinal fluid analysis is required to distinguish viral from bacterial causes and to identify the pathogen. [2] Lumbar puncture and CSF testing are typical components of the diagnostic workup for suspected meningitis. [2] VZV testing can be performed when CNS infection is suspected in the setting of zoster. [3]
Antiviral treatment when VZV CNS infection is suspected
Acyclovir is recommended for herpes simplex encephalitis. [5] Acyclovir is identified as the drug of choice for varicella-zoster virus–associated encephalitis based on case reports and small series. [5] Patients with herpes zoster meningitis are treated with acyclovir. [6]
Initiation thresholds for urgent care
Emergency evaluation is indicated when any combination of the following is present during active shingles: [2]
- Fever with headache plus neck stiffness. [2]
- Altered level of consciousness or cognition. [2]
- Severe or rapidly worsening headache in proximity to a head or neck zoster outbreak with other neurologic symptoms. [2]
Common pitfalls to avoid
Delaying evaluation while attempting symptomatic treatment for severe headache during active zoster increases the risk of missing treatable CNS infection. [2] Assuming that meningitis is unlikely solely because the rash is on the skin can delay diagnosis because rare VZV CNS complications occur. [1]
Clinical targets of therapy
The clinical target is prompt identification and treatment of CNS infection during an acute zoster episode to reduce morbidity from encephalitis, meningoencephalitis, or meningitis. [1][5] The immediate target in suspected VZV CNS infection is timely initiation of antiviral therapy while diagnostic results are pursued. [5][6]