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Neonatal Herpes Simplex Virus

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Neonatal Herpes Simplex Virus, Neonatal HSV, Congenital Herpes Simplex Virus

  • See Also
  1. Genital Herpes
  2. Neonatal Sepsis
  3. Herpes Simplex Encephalitis
  • Epidemiology
  1. Incidence: 1 per 3,000 to 20,000 live U.S. births
  2. Prevalence of HSV II seropositivity in U.S. adults: 25%
  3. HSV seroconversion during pregnancy: 2-3%
  • Pathophysiology
  1. Vertical transmission from mother
    1. Vaginal Delivery with active Genital Herpes lesions
  2. Highest risk if primary HSV outbreak in third trimester
    1. Risk of transmission during primary HSV outbreak: 33%
    2. Risk of transmission during secondary HSV: 3%
  3. Many women are asymptomatic
    1. In known Neonatal HSV, only 30% mothers symptomatic
  • Risk Factors
  1. Maternal HSV at time of delivery (highest risk)
    1. HSV is asymptomatic in nearly two thirds of mothers
    2. Exercise a low clinical threshold for testing
  2. Fetal scalp electrode use
  3. Vaginal Delivery
  • Precautions
  1. Poor outcomes are seen even with early diagnosis, but outcomes are worse with delayed diagnosis
    1. Exercise a low threshold in starting Acyclovir when Neonatal HSV is considered
  2. Neonatal HSV presentations are often cryptic
    1. Fever may be sole presentation with absent Vesicles
    2. Mother is frequently asymptomatic at time of delivery
  • Findings
  1. Irritability
  2. Fever
  3. Lethargy
  4. Poor feeding
  5. Ill appearing newborn
  • Signs
  • Perinatal Transmission
  1. Vesicular Lesions onset at ~21 weeks of life
    1. Skin HSV lesions absent in 50% of disseminated cases
    2. Eye or mouth HSV vesicular lesions
  2. HSV Encephalitis
  3. Other disseminated HSV infection sites
    1. Lung
    2. Liver
    3. Adrenal Glands
  • Signs
  • Congenital HSV Infection (in utero transmission)
  1. Microcephaly
  2. Hydrocephalus
  3. Chorioretinitis
  4. Hepatomegaly
    1. Helps differentiate from Erythema Toxicum Neonatorum
  • Labs
  • Culture sites (repeat weekly)
  1. Culture vesicular fluid for HSV
    1. Culture any vesicular rash in infant under 2 months
  2. Blood Culture for HSV
  3. Urine Culture for HSV
  4. CSF Culture and PCR for HSV
  5. HSV Culture of fluid from Eyes, nose and mucosa
  6. Liver transaminases (ALT, AST)
  • Management
  1. Consider rule-out Neonatal Sepsis protocol concurrently
    1. Start Acyclovir early and with a low threshold
    2. Fever and CSF Pleocytosis confers a 1% risk of HSV Encephalitis
  2. Acyclovir 30 mg/kg/day IV every 8 hours
  3. Duration of Antiviral therapy
    1. Local involvement (e.g. eyes): 14 days
    2. Disseminated or CNS involvement: Per local Consultation
  • Complications
  1. Neonatal Seizure disorder
  2. Psychomotor retardation
  3. Spasticity
  4. Learning Disability
  5. Blindness
  • Prognosis
  • Mortality
  1. Localized (Skin, eyes, mouth): No increased mortality
  2. HSV Encephalitis: 15% mortality
  3. Disseminated HSV: 57% mortality
  • References
  1. Claudius in Majoewsky (2012) EM:Rap 12(11): 7-8
  2. Kohl in Behrman (2000) Nelson Pediatrics, p. 966-72
  3. Kimberlin (2001) Pediatrics 108(2):223-9 [PubMed]
  4. Kimberlin (2001) Pediatrics 108(2):230-8 [PubMed]
  5. Rudnick (2002) Am Fam Physician 65(6):1338-42 [PubMed]
  6. Snyder (2024) Am Fam Physician 109(3): 212-6 [PubMed]