Jaspen et al attempt to find clinical clues which may herald HIV infection in exposed neonates in South Africa:
417 HIV-infected and 125 HIV-exposed, uninfected infants, median age 46 days (IQR 38-55), were included. The median CD4 percentage in HIV-infected infants was 34 (IQR 28-41)%. HIV-infected infants had lower weight-for-age, more lymphadenopathy, oral thrush, and hepatomegaly than exposed uninfected infants (Adjusted Odds Ratio 0.51, 8.8, 5.6 and 23.5 respectively; p<0.001 for all). Sensitivity of individual signs was low (<20%) but specificity high (98-100%). If any one of oral thrush, hepatomegaly, splenomegaly, lymphadenopathy, diaper dermatitis, weight <50th centile are present, sensitivity for HIV infection amongst HIV-exposed infants was 86%. These algorithms performed similarly when used to predict severe immune suppression.
Neonatal HIV can be notoriously hard to diagnose. In the developed world, we screen patients of all ages for HIV with a rapid, anti-body test, but then confirm it with a more advanced PCR test. In neonates, however, because they get maternal antibodies in utero and through breast milk, the anti-body tests could be a 'false-positive' - i.e. the test says positive, but it's actually false because it's detecting the mother's transmitted anti-bodies. So the general strategy in the developed world is to skip the preliminary (less costly) antibody test and go directly to the (more expensive) PCR test.
This strategy fails in the undeveloped world where the (more expensive) PCR tests aren't available. The two prevailing strategies are a) look for very much cheaper antibody tests and b) look for ways to clinically screen patients and then refer only the higher suspicion ones to get the more expensive tests (as Jaspen et al have done).
Strategy A is the preferred way and some money is being spent on that. My preference would be that more money be spent on that. In the meanwhile, those nurses/house officers/doctors have to 'get through the day' with whatever tools they have. And if they find that more lymphadenopthy can increase the clinical probability that a neonate has HIV, they may feel more confident sending that mother and baby by bus over many kilometers to a more sophisticated testing and treating center.
It's suboptimal. But until we get better and cheaper tests, it's the prudent field level strategy.
Comments