Originally published at Pediatric EM Morsels on December 9, 2011. Reposted with permission.

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Neonatal HSV is a rare condition, but one that results in devastating Morbidity and Mortality; therefore, it is imperative that we keep it on our radar and stay vigilant for it!

Neonatal HSV

• Neonatal HSV is a rare disease (although likely under-reported): 1/2000 – 1/5000 live births.
• Has 3 main classifications:
  • SEM (Skin, Eye and/or Mouth) – unlikely to lead to death
  • Encephalitis – associated with ~15% mortality
  • Disseminated – associated with ~57% mortality

It is difficult to diagnose clinically!!

• Maternal history of HSV is important… but, only 12-22% of neonates diagnosed with HSV were born to mothers with a history of genital HSV (so ~80% had no maternal history of HSV).
• SEM has tell-tale vesicular lesions… so that isn’t too difficult, but…
• The more concerning HSV encephalitis and disseminated HSV are the most difficult to detect clinically, especially early on.
• Because of this and the significant M&M associated with them, we must have high index of suspicion for it.

• Findings that should heighten your suspicion for HSV:

  • Seizures
  • Disseminated Intravascular Coagulation
  • Elevated Liver Enzymes
  • CSF pleocytosis
  • TOXIC appearance and/or true lethargy

The question is then, in the well-appearing neonate with a fever, should you start acyclovir?

What it boils down to:

• The child 0-30 days with fever should have full-sepsis work-up.
  • If they appear Toxic, in addition to resuscitating them and giving traditional antibiotics, you should send CSF for HSV PCR and start Acyclovir.
  • If the patient is well-appearing, do the traditional full-sepsis work-up. If the CSF has a pleocytosis, then order the HSV PCR and start the acyclovir.

• DO NOT, send the HSV PCR and hold the acyclovir – Delayed acyclovir is associated with higher mortality (plus you just announced to the world that you were concerned for HSV, but you didn’t do anything about it).
• DO NOT, start acyclovir without sending HSV PCR (unless the kid is too toxic for an LP) – kind of makes determination of duration of therapy difficult.

• Unfortunately there is a paucity of literature that we can base this answer upon.
• See AAEM Clinical Practice Guideline on Neonatal HSV for full review.

AAEM Clinical Practice Guideline on Neonatal HSV

Shah SS, Aronson PL, Mohamad Z, Lorch SA. Delayed Acyclovir Therapy and Death Among Neonates With Herpes Simplex Virus Infection. Pediatrics 2011; 128; 1153-1160.