SAN DIEGO — Any physician who cares for newborns should consider neonatal herpes simplex virus infection a must-make diagnosis, Dr. Richard F. Jacobs said.
"This is one of my top 10 'please don't let me miss this' diagnoses," said Dr. Jacobs, a longtime member of the National Institutes of Health's Collaborative Antiviral Study Group. "You can't miss this diagnosis because HSV untreated has a natural history that is truly horrible."
An estimated 15%-20% of women of childbearing age have latent HSV infection that would be a potential factor in pregnancy. The risk of transmission to offspring is believed to be about 50% in mothers who have a primary infection and skin lesions present and 3%-4% in mothers with a recurrent infection and skin lesions present. Actual neonatal disease is about 1 per 7,500 live births.
"Visible lesions would be an automatic indication to go to C-section unless there have been prolonged ruptured membranes," Dr. Jacobs said at a meeting sponsored by Rady Children's Hospital and the American Academy of Pediatrics. "With prolonged ruptured membranes, you don't get any benefit from C-section."
Neonatal HSV presents as one of three clinical types: skin, eye, or mucous membranes (SEM); central nervous system (CNS); or disseminated. Neonates with SEM HSV present at a mean 11 days old and have discrete skin vesicles in 80% of cases. "That means that you have to look carefully for the other 20% during your clinical exam," said Dr. Jacobs, who is also chair of pediatrics at the University of Arkansas, Little Rock. "Look in any mucous membrane, anywhere on the skin. You can find them in the conjunctiva or in the mouth." A CSF polymerase chain reaction (PCR) that is negative is required to make the diagnosis of the SEM form of HSV.
If the SEM form of the disease goes untreated, 70% of cases will progress to CNS or disseminated disease. The recommended course of treatment is 20 mg/kg per dose of acyclovir every 8 hours for 2 weeks. "People with cold sores can transmit to the skin of newborns, but all of these babies will be normal if you treat them," Dr. Jacobs said. "Survival is 100% if they're treated."
Neonates with the CNS form typically present with encephalitis virus at a mean 16 days old, likely caused by retrograde axonal transmission of HSV. An infant may get HSV in the nose or eyes that spreads transneuronally to the brain, but the CNS form of neonatal HSV doesn't present like sepsis, he explained.
Other telltale signs include fever and lethargy for 1-2 days followed by the sudden onset of nearly intractable seizures. Initially the infection is localized to the temporal lobes, but it spreads to the brainstem. If the infection goes untreated, the mortality is greater than 50%. With acyclovir treatment the mortality is 15%.
Neonates with the disseminated form of HSV disease present at a mean 11 days old with symptoms that mimic sepsis. Encephalitis is present in 60%-70% of cases; pneumonitis and hepatitis/coagulopathy also are common. The process involves a blood-borne seeding of the CNS, with multiple areas of cortical hemorrhagic necrosis. If the disseminated form of the disease goes untreated, the mortality exceeds 80%. With acyclovir treatment the mortality is greater than 50%, Dr. Jacobs said.
Only about one-half of neonates with the CNS or disseminated forms of disease have cutaneous lesions. "If you do see a cutaneous skin lesion with an ulcerative base that is necrotic, that is HSV in a baby until proven otherwise," Dr. Jacobs said. "I don't care if that fluid is clear, cloudy, or green."
Dr. Jacobs reported that he had no conflicts to disclose.
If you see a 'skin lesion with an ulcerative base that is necrotic, that is HSV in a baby until proven otherwise.' DR. JACOBS