Risk of transmission is determined by maternal serostatus at time of maternal genital infection
Newly acquired
First-episode primary infection (mother has no serum antibodies to HSV-1 or -2 at onset): risk of transmission is about 60%
First-episode nonprimary infection (mother has a new infection with one HSV type in the presence of antibodies to the other type): risk of transmission is less than 30%
Recurrent (mother has pre-existing antibodies to the HSV type that is isolated from the genital tract): risk of transmission is less than 2%
Pathophysiology
Generally acquired at time of delivery, though 5-8% may be congenital
Localized CNS infection is thought to occur by retrograde axonal transmission
Clinical Manifestations
Incubation period 7 to 21 days post-partum, with range from birth to 6 weeks
Spectrum of disease from cutaneous to disseminated
Disseminated disease
25% of cases
Sepsis syndrome that predominantly affects the liver, lungs, and CNS
May not have skin findings (25%)
CNS involved in 60-75%, causing meningoencephalitis
Can also affect larynx, trachea, esophagus, stomach, lower gastrointestinal tract, spleen, kidneys, pancreas, and heart
Later in the course of the disease, may develop elevated ALT/AST and direct bilirubin, as well as coagulopathy and thrombocytopenia
Usually presents in the first or second week of life
Should be considered in sepsis without bacterial cause and with liver dysfunction or coagulopathy
Localized CNS disease
30% of cases
Usually presents in the second or third week of life
May not have cutaneous manifestations
Can cause seizures
Skin, eye, and mouth disease
45% of cases
Localized to skin, eyes, and/or mouth
Usually presents in the first or second week of life
Diagnosis
Most commonly diagnosed with PCR of lesions, CSF, or mucosal membranes (conjunctivae, mouth, nasopharynx)
Do not send superficial swabs for PCR during the first 24 hours of life, since this can generate false positive from superficial contamination from the birthing process
Early CSF PCR may be falsely negative; consider continuing acyclovir and repeating at 72 hours if high clinical suspicion
Management
Diagnosed neonates
Obtain CSF (± blood PCR), and transaminases to determine if the disease involves CSF and is disseminated
Disseminated disease: high-dose acyclovir 60 mg/kg/day IV divided q8h for at least 21 days
If CNS disease, repeat lumbar puncture at the end of therapy to document resolution of CSF parameters and ensure that PCR is negative
Localized CNS disease: same as for disseminated
Localized skin, eye, and mouth disease: high-dose acyclovir 60 mg/kg/day IV divided q8h for at least 14 days
For eye involvement, consult and ophthalmologist to add topical trifluridine, idoxuridine, or vidarabine
Exposed neonates
First-episode genital HSV at delivery
Rupture of membranes before vaginal or cesarean delivery
Swab mucous membranes for PCR either at birth or at 24 hours
