Febrile syndrome in children younger than 29 days

Abstract

Acute fever of unknown origin (FUO) in children under 29 days is a worrying situation because of the risk of serious bacterial infection (SBI).

Objective: to study the main clinical and laboratory characteristics of a group of hospitalized children under 29 days with diagnosis of FUO.

Patients and Method: Retrospective study of children under 29 days hospitalized due to FUO. The clinical records of the patients were reviewed, recording age, sex, history of fever before consultation, temperature at admission, estimated severity at admission and discharge, discharge diagnoses, laboratory tests, and indicated treatments. Patients were classified according to the severity of the discharge diagnosis, as severe (S) and non-severe (NS). The inclusion criteria were term newborn, age less than 29 days, fever ≥ 38°C registered at home or admission, and history of < 4 days.

Results: 468 children with FUO were admitted. Concordance between severity at admission and discharge was low (Kappa = 0.125; p = 0.0007). 26.1% of children were S and 73.9% NS. In the S group, urinary tract infection domínate (70.5%) and in the NS, FUO (67.6%). The cut-off levels for leukocytes/mm3 , C-reactive protein, and neutrophils/mm3 showed negative predictive values to rule out severe bacterial infection.

Conclusions: Most of the newborns presented mild severity at admission, but 24% of them had SBI, thus hospitalization and close clinical observation are always necessary. Laboratory tests, such as CRP, white blood cell and neutrophils count are not good predictors of SBI. Early treatment with antibiotics for patients who meet the low-risk criteria is debatable.