A few years ago when I was chair of the Canadian Paediatric Society Fetus and Newborn Committee, we produced a statement about what to do with full term babies with risk factors for sepsis. Our recommendation was, to put it simply, for risk factors screen and observe, for clinical signs culture and treat. One risk factor that we had a lot of debate about was chorioamnionitis. The overall frequency of early onset sepsis is high after confirmed chorioamnionitis (as high as 8% in some studies), but placental pathology or cultures to get a confirmed diagnosis take too long to make a treatment decision. There are also data that infants who appear well at birth, despite definite, chorioamnionitis are at much lower risk, so we recommended screening and close observation, as long as the baby remained well.
Clinical diagnosis of chorioamnionitis is very unreliable, fever during labour may be due to multiple other causes, and when the obstetrician suspects chorioaminonitis many patients don’t have pathologically confirmed disease (only a third of them are histologically positive if the main sign is fever).
Shortly thereafter the CDC published some standards which counseled that all babies with a history of ‘Chorioamnionitis’ get cultures and antibiotics.
I think that is not unreasonable if you look at the scary 8% figure: if you can treat empirically a group of patients with an 8% chance of having a positive blood culture then that would be a good thing. In practice however, with the poor ability to clinically diagnose chorioamnionitis and the low incidence of disease in babies who look well at birth, there is a good chance that to follow such advice will end up treating hundreds of babies for every positive culture.
The most recent version of the AAP position statement, or clinical report or whatever they call them, recommends antibiotic therapy for all babies born after chorioamnionitis, and even if the cultures are negative to continue antibiotics for 7 days if the screening lab tests (a CBC and differential adn a CRP) are abnormal.
What actually happens if you do that? Kiser C, Nawab U, McKenna K, Aghai ZH: Role of Guidelines on Length of Therapy in Chorioamnionitis and Neonatal Sepsis. Pediatrics 2014. This study shows that following the AAP strategy leads to large numbers of healthy-appearing babies with negative cultures receiving prolonged antibiotic therapy. Of 554 term and late preterm babies exposed to chorioamnionitis, 134 of them had 7 days of antibiotics, in 112 of those cases it was solely because the lab tests were abnormal.
This story highlights the difficulty of writing guidelines, you may have unintended consequences, even with the best of intentions. Interestingly the Swiss neonatal association guidelines are very similar to the CPS, with treatment only for those who develop clinical signs.
As a result of concerns about over-long treatment in healthy babies, the AAP have now revised their guideline, although they still recommend starting the antibiotics, even in healthy appearing infants, they no longer recommend prolonging therapy beyond 48 to 72 hours if the infant remains well. A step in the right direction.
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