Neurology -- Correspondence for De Tiège et al., 61 (2) 241-243

Correspondence published:

Acyclovir Dosage to Prevent Relapse of Herpes Simplex Encephalitis: Huei-Shyong Wang (4 September 2003)

Acyclovir Dosage to Prevent Relapse of Herpes Simplex Encephalitis 4 September 2003

Huei-Shyong Wang,
Division of Pediatric Neurology, Chang Gung Children’s Hospital
199 Tung-Hwa N. Rd., Taipei, 105, Taiwan
Send Correspondence to journal:
Re: Acyclovir Dosage to Prevent Relapse of Herpes Simplex Encephalitis

wanghs444{at}cgmh.org.tw Huei-Shyong Wang

The article by De Tičge et al.[1] may help clinicians differentiate between two neurologic entities of relapsing herpes simplex encephalitis (HSE) in children. One is immune-mediated parainfectious relapse presenting with choreoathetosis that occurred about 2 weeks after cessation of acyclovir treatment for the initial HSE without new necrotic-hemorrhagic brain lesions and intrathecal production of alpha-interferon. The other is replication of herpes simplex virus (HSV) with new necrotic-hemorrhagic brain lesions and sometimes intrathecal production of alpha-interferon without choreoathetosis that occurred from a few days to years after initial HSE.
Treating the parainfectious relapse with further acyclovir treatment is not reasonable. Corticosteroids, immunoglobulin, or immunosuppressants may help. Early use of those medications depends on the alertness of clinicians to detect the presentation of choreoathetosis as an initial sign of this type of HSE relapse. [2]
For the HSV-replication relapse, more acyclovir treatment may help. De Tičge et al. recommend that a minimum of 15 days of acyclovir (45 mg/kg/day) may prevent the viral-replication relapse, especially for the early relapse in a few days. However, most of their cases received 60 mg/kg/day for 3 weeks. For those late relapses that may relate to an innate HSV-specific immune deficiency or familial high HSV susceptibility, more efficient treatment may include a combination of multiple antiviral agents or long-term oral acyclovir administration. The varying doses and durations of acyclovir administration by De Tičge et al may clarify the case-by-case variations in HSE. Treatment for HSE is not complete until negative results of CSF on PCR are confirmed at least twice, rather than to blindly administer acyclovir for 2 or 3 weeks. [3] The necessity of subsequent oral acyclovir or valacyclovir for extended periods needs further evaluation.
In addition, there may by another type of virus causing relapse besides HSV, such as Coxsackievirus A9 reported by Ito et al [4].
References
1. De Tičge X, Rozenberg F, Des Portes V, et al. Herpes simplex encephalitis relapses in children: Differentiation of two neurologic entities. Neurology 2003;61:241-643.
2. Wang H-S, Kuo M-F, Huang S-C, Chou M-L. Choreoathetosis as an initial sign of relapsing of herpes simplex encephalitis. Pediatr Neurol 1994;11:341-345.
3. Pike MG, Kennedy CR, Neville NG, et al. Herpes simplex encephalitis with relapse. Arch Dis Child 1991;66:1242-1244.
4. Ito Y, Kimura H, Yabuta Y, et al. Exacerbation of herpes simplex encephalitis after successful treatment with acyclovir. Clin Infect Dis 2000;30:185-187.