HERPES SIMPLEX (HSV)

HSV, usually type 2 and occasionally type 1, generally infects the infant during intrapartum period following contamination by infected external genitalia.
A proportion of the infants acquire the infection during intrauterine life,or from mother or caretaker during postnatal period.


Clinical features
Abortion may be the outcome of the infrequent fetal infection occurring in early in pregnancy.
Three clinical patterns of neonatal infection are known, namely 1.disseminated disease 2. skin-eye mouth disease , and 3. encephalitis.
Disseminated disease is characterized by multi organ involvement with lesions in skin, lungs, trachea, CNS, esophagus, kidney, adrenals, spleen, heart, etc. Manifestations, which starts from 4 th to 10th day after birth, mimic fulminant septicemia. These include fever, apnea, respiratory distress, seizures, lethargy, irritability, conjugated hyperblirubinemia, shock, DIC and vesicles.
Skin-eye-mouth disease is characterized by cutaneous vesicles and ocular lesions ( kerato-conjunctivitis, later chorioretinitis, micropthalmia, cataracts). If not treated with antiviral therapy, this type may progress to disseminated disease.
Encephalitic disease , isolated due to retrograde axonal transmission of virus to CNS and not viremia, is characterized by pyrexia, irritability, lethargy, change in sensorium (even coma), seizures, bulging fontanel, high-pitched cry and focal temporal lesions on CT scan, or ECG.
Diagnosis
HSV can be isolated in tissue cultures obtained from vesicles, nasopharyngeal or throat swabs, urine, stool, tracheal secretions, duodenal aspirate and CSF.
Additional tests include specific fluorescent antibody, CMV inclusion cells in urine, paired maternal and cord sera for complement fixation antibody.
Treatment
Two antiviral agents, acyclovir and vidarabine, are recommended. Acyclovir is particularly superior to vidarabine is HSV encephalitic disease.
Topical antiviral agents for opthalmic involvement include vidarabine, idoxuridine and trifluorothymidine.
Prevention
Mothers with genital herpes should have delivery by cesarean section. The later should preferably be done within 4 to 6 hours of rupture of membranes.
Prognosis
Disseminated and encephalitic herpes have worse prognosis than skin-eye-mouth herpes. HSV type 1 encephalitis has better outcome than HSV type 2 encephalitis.