Height of fever and invasive bacterial infection

Area of Science:

• Pediatrics
• Infectious Diseases
• Neonatal Care

Background:

• Febrile infants under 60 days old pose a diagnostic challenge.
• Identifying invasive bacterial infections (IBI) early is crucial for appropriate treatment.
• The relationship between fever severity and IBI risk in neonates requires further clarification.

Purpose of the Study:

• To investigate the association between fever height and the likelihood of invasive bacterial infection (IBI) in infants aged 60 days or younger.
• To determine the diagnostic utility of different temperature ranges for IBI in febrile infants.

Main Methods:

• Secondary analysis of a multicenter case-control study involving non-ill-appearing febrile infants up to 60 days old.
• Comparison of maximum recorded temperatures (home or ED) between infants with and without IBI.
• Calculation of interval likelihood ratios (iLRs) for IBI across various temperature intervals (0.5°C increments).

Main Results:

• Infants with IBI had a higher median temperature (38.8°C) than those without (38.4°C).
• Temperatures between 39°C-39.4°C (iLR 2.49) and 39.5°C-39.9°C (iLR 3.40) increased the likelihood of IBI.
• A significant proportion (30.4%) of febrile infants with IBI presented with maximum temperatures below 38.5°C.

Conclusions:

• While higher fever temperatures correlate with an increased likelihood of IBI in infants, fever height alone is not a definitive diagnostic marker.
• Fever severity should be considered alongside other clinical factors for comprehensive risk stratification.
• The study highlights the need for cautious interpretation of fever height in diagnosing IBI in young infants.