HERPES SIMPLEX IN INFANTS

See also general section on "Herpes Simplex" which includes a discussion of perinatal management of HSV infection

I. General issues

  1. Neonates: HSV II is more common; with older pts: us. HSV I (95%)
  2. Variants of neonatal disease
    1. Localized disease (skin, eyes, and/or mouth)--most common; not ass'd with increased mortality but may progress to #2 or #3
    2. CNS disease (see below)--mortality 15%
    3. Disseminated disease--mortality 57%
  3. If vag. birth with lesions, culture baby's eyes, pharynx, rectum <24h post-partum
  4. Some believe should give baby acyclovir even if no obvious inf. & cx are neg. (perinatally acquired HSV us. doesn't form local disease)

II. HSV Encephalitis:

  1. Epidemiology
  1. Seen in all age groups
  2. Most common nonepidemic encephalitis in U.S.
  3. Annual incidence 1:500K
  1. Pathogenesis
  1. Unknown; us. occurs after other primary (e.g. cutaneous) dis., but can occur as primary, & 1 study showed diff. oropharyngeal & cerebral strains in 3/8 pts
  2. Pathology shows cortical involv., esp. temporal lobe
  3. Host immune status thought to be involved
  1. Clinical features:
  1. High mortality (70% without tx); freq. serious sequelae
  2. Neonatal HSV encephalitis
  1. Becoming more common; us. cong., 2? to mom's HSV lesion in birth canal
  2. Occurs as part of gen'lized viremia w/Type II (80% mort.) or localized CNS inf. (50% mort.; 34% with tx)
  3. Sequelae: MR, microcephaly, hydrancephaly, porencephaly, spastic quadriplegia, blindness
  1. Post-neonatal
  1. May simulate brain abcess or bulbospinal polio
  2. Us. subacute onset, fvr, HA, MS G's x sev. days
  3. Progressive focal neuro sx; sz
  4. Halluc. can result from involv of temporal/limbic
  5. May recur after full course of Acyclovir
  1. With cellular immune dysfn, has subacute deteriorating course; us. HSV II
  2. Aseptic meningitis w/concommitant genital inf (us. HSV II)
  3. Post-viral encaphalitic sd.
  1. Diff Dx:
  1. Arbovirus, Enterovirus
  2. Cerebrovasc. dis.
  3. Bact. (subdural empyema; abcess)
  4. Fungal
  5. Tumor
  1. Dx:
  1. Radionucleide brain scan
  2. EEG--80% sens.--local spike & slow waves--but not specific
  3. CSF studies--CSF can be completely nl
  1. Us. high opening press
  2. Often bloody but doesn't help in dx of HSV
  3. Initially, lots PMNs, then Lymphos (50-500)
  4. High protein, nl glu
  5. Serum:CSF relative titers (slow to change)
  1. Brain Bx with SEM, Cx, or immunofluorescence (only definitive diagnostic modalities)
  2. Viral cx of CSF is highly insensitive except in disseminated HSV
  3. CT is 60% sens.
  4. PCR
  1. Tx:
  1. Acyclovir 30mg/kg/d x 10-14d
  1. Reduces mort from 70%-->19%
  1. Adenosine arabinoside (Vidarabine)
  1. Viral chain terminator
  2. Reduces mort from 70%-->50%
  1. Poor prognostic indicators:
  1. Severe CT scan findings
  2. Dissemination in neonates, esp. pneumonitis
  3. Unconsciousness @ tx onset
  4. Relapse 2-3mos post onset
  5. Increased age