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(See also Herpesviruses: Herpes Simplex Virus (HSV) Infections.)
Neonatal herpes simplex virus infection is usually transmitted during delivery. Signs are typically a vesicular eruption and subsequent disseminated disease. Diagnosis is by viral culture, PCR, immunofluorescence, or electron microscopy. Treatment is with high-dose parenteral acyclovir and supportive care.
Neonatal herpes simplex virus (HSV) infection has high mortality and significant morbidity. Incidence estimates range from 1/3,000 to 1/20,000 births. HSV type 2 causes more cases than HSV type 1.
HSV is usually transmitted during delivery through an infected maternal genital tract. Transplacental transmission of virus and hospital-acquired spread from one neonate to another by hospital personnel or family may account for some cases. Mothers of neonates with HSV infection tend to have newly acquired genital infection, but many have not yet developed symptoms at the time of delivery.
Symptoms and Signs
Manifestations generally occur between the 1st and 2nd wk of life but may not appear until as late as the 4th wk. Patients may present with local or disseminated disease. Skin vesicles are common with either type, occurring in about 55% overall. Those with no skin vesicles usually present with localized CNS disease. In patients with isolated skin or mucosal disease, progressive or more serious forms of disease frequently follow within 7 to 10 days if left untreated.
Localized disease:
Neonates with localized disease can be divided into 2 groups. One group has encephalitis manifested by neurologic findings, CSF pleocytosis, and elevated protein concentration, with or without concomitant involvement of the skin, eyes, and mouth. The other group has only skin, eye, and mouth involvement and no evidence of CNS or organ disease.
Disseminated disease:
Neonates with disseminated disease and visceral organ involvement have hepatitis, pneumonitis, disseminated intravascular coagulation, or a combination, with or without encephalitis or skin disease.
Other signs, which can occur singly or in combination, include temperature instability, lethargy, hypotonia, respiratory distress, apnea, and seizures.
Diagnosis
Rapid diagnosis by viral culture or HSV PCR is essential. The most common site of retrieval is skin vesicles. The mouth, eyes, and CSF are also high-yield sites. In some neonates with encephalitis, virus is present only in the brain. Diagnosis also can be made by immunofluorescence of lesion scrapings, particularly with use of monoclonal antibodies; and electron microscopy. If no diagnostic virology facilities are available, a Tzanck test of the lesion base may show characteristic multinucleated giant cells and intranuclear inclusions, but this test is less sensitive than culture, and false-positives also occur.
Prognosis
The mortality rate of untreated disseminated disease is 85%; among those with untreated encephalitis, it is about 50%. Without treatment, at least 65% of survivors have severe neurologic sequelae.
Death is uncommon in neonates with local disease limited to the skin, eyes, or mouth. However, without treatment, many of these neonates will progress to disseminated disease or CNS disease that may be unrecognized; about 30% develop neurologic impairment, which may not manifest until 2 to 3 yr of age.
Treatment
Acyclovir decreases the mortality rate in CNS and disseminated disease by 50% and increases the percentage of children who develop normally from about 35% to 50 to 80%; the dose is 20 mg/kg IV q 8 h for 21 days. Vigorous supportive therapy is required, including appropriate IV fluids, alimentation, respiratory support, correction of clotting abnormalities, and control of seizure disorders.
For localized disease (skin or mouth), treatment is acyclovir 20 mg/kg IV q 8 h for 14 days. Herpetic keratoconjunctivitis requires concomitant systemic acyclovir for 14 days and topical therapy with a drug such as trifluridine, iododeoxyuridine, or vidarabine (see Infections in Neonates: Treatment).
Prevention
Efforts to prevent neonatal transmission have not been very effective. Universal screening has not been recommended or shown to be effective, and most maternal infections with risk of transmission are asymptomatic. However, cesarean delivery for women known to have a high risk of transmission (eg, active genital lesions present at term) has been shown to decrease transmission and is recommended. Also, fetal scalp monitors should not be used during labor on infants whose mothers have suspected active genital herpes.
Last full review/revision October 2009 by Mary T. Caserta, MD
Content last modified October 2009
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