Written by Clay Smith
Height of fever in febrile infants was associated with serious bacterial illness (SBI). For every 0.5 degree Celsius increase in temperature, odds of SBI increased 48%.
Why does this matter?
A systematic review of 11 studies found that infants under 3 months with fever >40C (104F) had over 6 times greater odds of SBI. A more recent study also showed height of fever matters. Most were case-control or cross-section study designs. If you haven’t heard the ERcast episode Rob Orman and I did on pediatric fever, you will want to listen (subscription required). This study was a planned secondary analysis of the prospectively collected PECARN data.
There’s fever…and there’s FEVER
Using the information collected by the PECARN group prospectively from 26 EDs, 4,821 febrile infants <60days, they determined that the height of fever was associated with SBI. Overall prevalence of SBI was 9.2%. Having fever in the ED vs at home was associated with 40% greater odds of SBI, especially UTI (OR 1.4, 95% CI 1.1–1.8). That said, prior studies have shown that reported fever by a parent vs recorded fever in the ED should be managed the same. The big finding of this study was that height of fever was associated with risk of SBI, OR 1.48 (95%CI 1.35–1.63). In other words, for every 0.5 degree C increase, odds of SBI increased 48%. Another way to look at the absolute risk is, “a temperature < 39C still had a 9.1% risk of SBI. Among children with a fever > 39C, though, the risk of SBI doubled to 20.4%.” This figure says it all.
Fever Characteristics and Risk of Serious Bacterial Infection in Febrile Infants. J Emerg Med. 2019 Aug 7. pii: S0736-4679(19)30489-5. doi: 10.1016/j.jemermed.2019.06.028. [Epub ahead of print]
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Reviewed by Thomas Davis