Herpes and congenital infection

Next is herpes and this is a newspaper from right after acyclovir was first licensed. The main situation with herpes is that the congenital infection is only a small part. The major problem with herpes is acquisition of virus infection during the birth process. So the congenital infection is actually rare but it is virtually always severe and almost never without residual. The important thing is a vesicular rash at birth and I’ve seen some real tragedies, because the vesicles here people look and think they are going see a vesicle like you see in a cold sore or what you see in older people with herpes. These vesicles are very thin-walled and they break very easily, and I’ve seen a tragedy where these vesicles were looked at and they said, “Well, they are not herpes.” So they can be very thin and not looking at all like what you would expect to find. Low birth weight, chorioretinitis, brain damage, small for gestational age, microcephaly, intracranial calcifications, microphthalmia and cataracts. This is a baby with congenital varicella who right at birth had vesicular lesions right here.

The diagnosis again is culture. Herpes should grow out. Culture of lesions, if you have lesions, also culture from many sites; throat, blood buffy coat, urine, CSF and also direct antigen tests which are quicker and also PCR from CSF. One thing about PCR from CSF in newborns; it is the percent positive in only about 75% whereas older people with herpes encephalitis, it’s close to 95%. Lastly, specific IgM antibody. Treatment of course is acyclovir and in general, one of the mistakes that’s made is not to treat long enough and also to use too low a dose. The dose that’s indicated in most of the literature is 10 mg/kg per dose three times a day. But regularly, particularly in congenital infections, you should push this to 45 mg/kg per day and give it for at least three weeks and then evaluation because some of these should go on long term therapy.

Next is congenital infection with varicella and there are two events. Early infection in pregnancy and then infection right before birth, maternal infection right before birth. The infections of the mother early in pregnancy, first of all is not too common and transmission to the baby is relatively rare. In fact the earlier epidemiologic literature said there was no risk. But then people noted a very specific syndrome, particularly with limb atrophy. More recent studies suggest the risk is somewhere around 2-3% of mothers infected in the first 20 weeks. Your findings are scars and hypopigmentation, hypoplasia of limbs, encephalitis and cortical atrophy. Most of these babies do very poorly. Low birth weight, immune defects, are the findings that you have here. Sometimes we’ve seen several babies with just chorioretinitis, no other findings. Frequently that plus some scars like they have apparently had some chicken pox-like lesions in utero and now they are scabbed over.

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