Neonates with isolated historical fever likely at lower risk for serious bacterial infection

1. In this retrospective cohort study, infants with a history of fever but without fever on presentation to the hospital or subsequent fever while hospitalized were significantly less likely to have a serious bacterial infection (SBI) as compared to infants that were febrile on presentation.

2. Among patients with a history of fever who were afebrile on presentation, only about a quarter developed fever during their subsequent hospitalization.

Evidence Rating Level: 2 (Good)

Study Rundown: Though fever is considered a medical emergency in neonates, many infants presenting to the emergency room with a history of recent fever are afebrile on presentation. In this paper, researchers explored the outcomes of infants who presented to the hospital with a history of fever but without fever at the time of presentation. Outcomes explored included the development of SBIs including urinary tract infection, bacteremia, and bacterial meningitis, as well as development of invasive bacterial infections (IBIs), which specifically targeted only bacteremia and bacterial meningitis. Completing a retrospective cohort study, researchers found that infants who were afebrile on presentation, but never developed fever during hospitalization were significantly less likely to have an SBI than those infants who were febrile on presentation. There was no difference, however, in the rates of invasive bacterial infection between these two groups. Additionally, of patients who presented with a history of fever, only about a quarter went on to develop a fever during their hospitalization. This study is limited by the inherent constraints of a retrospective study and does not demonstrate a significant difference in rates of IBIs making its application limited. Still, the results do suggest the potential option of allowing patients who remain afebrile during their stay to be discharged earlier, given a lower likelihood of SBI, particularly after a short period of observation.

Click to read the original article in Pediatrics

Relevant Reading: Approach to Neonates and Young Infants with Fever without a Source Who Are at Risk for Severe Bacterial Infection

In-Depth [retrospective cohort]: Data included neonates (infants less than or equal to 28 days of age) who presented to a single center’s emergency department between January 1, 2006 to December 31, 2017 with a historical or documented fever (n = 2356). After filtering out patients based on various exclusion criteria, including lack of appropriate cultures and antibiotic treatment prior to culture, the remaining patients were divided into 3 categories: afebrile with no subsequent fever (ANF, n = 278, 55% male, mean age 17.9 days), afebrile with subsequent fever (ASF, n = 93, 54.8% male, mean age 20.8 days), and febrile on presentation (FP, n = 560, 54.1% male, mean age 18.9 days). Of the FP group, 10.4% had an SBI, compared to 18.3% of the ASF group, and 4.7% in the ANF group. The FP group had a statistically significant increased odds of developing a SBI in comparison to the ANF group (OR 0.42, 95%CI 0.23-0.79, p = .006). Of the patients with historical fever, 25.1% developed subsequent fever, with a mean time of 5.6 hours to first elevated fever.

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