The Febrile Infant

Abstract

Fever is a common complaint between children under 36 months of age. While most of febrile children are affected from viral infections, some infants can suffer from a serious bacterial infection (SBI). This article focuses on the child with fever without source (FWS) and the available diagnostic tools to estimate SBI risk and avoid unnecessary complementary tests and treatments, as well as their use in routine clinical practice in a Latin American country. The combination of medical history, physical examination, and complementary tests continues to being very important to take decisions on febrile infant. Procalcitonin, C-reactive protein, and absolute neutrophil count are the most relevant complementary tests to help us perform actions on infants with FWS with good clinical appearance and without risk factors. The evaluation and disposition of febrile infants is highly variable, particularly among infants between 29 and 60 days of age. If a child has bad appearance or the bacterial source of fever is definite, treatment needs to be started immediately. However, if febrile infant has FWS, has a good clinical appearance, and does not have risk factors in medical history, the complementary tests can be necessary to identify febrile infants with low SBI risk. The evaluation of SBI risk, and mainly of invasive bacterial infection—bacteremia and meningitis—, will continue to change according to new scientific researches; training and experience of physicians and availability of auxiliary tests; and, of course, sociocultural background. This is particularly important in low-resource settings; therefore, in children 1 to 2 months of age, it is preferable to establish a safer strategy to assess SBI risk and hospitalization should be considered.