Associated symptoms and delayed antimicrobial treatment in febrile urinary tract infection among children younger than 2 years.

OBJECTIVES

Febrile urinary tract infection (fUTI) is common in young children, but associated symptoms may suggest alternative febrile illnesses. This study clarified the prevalence of associated symptoms in children younger than 2 years with first-episode fUTI and evaluated their association with delayed antimicrobial treatment.

METHODS

We conducted a single-center retrospective cohort study of children younger than 2 years with first-episode fUTI between January 2010 and December 2024. Associated symptoms documented at the initial medical evaluation were categorized as cough/rhinorrhea, vomiting, diarrhea, seizure, other symptoms, or multiple symptoms. The primary outcome was the prevalence of associated symptoms. Secondary outcomes were days from fever onset to antimicrobial treatment and delayed antimicrobial treatment, defined as treatment initiation on or after the fourth calendar day of fever.

RESULTS

Among 420 children, fever alone was the most common presentation in 292 (69.5%). Associated symptoms were documented in 128 (30.5%), including cough/rhinorrhea in 56 (13.3%), vomiting in 19 (4.5%), diarrhea in 13 (3.1%), seizure in 15 (3.6%), other isolated symptoms in 4 (1.0%), and multiple symptoms in 21 (5.0%). Associated symptoms were more frequent in children aged 2-23 months than in infants younger than 2 months (33.9% vs. 13.0%; p < 0.001). Among 395 patients included in isolated symptom-specific analyses, older age and cough/rhinorrhea were associated with delayed treatment in the age-adjusted model. The association with cough/rhinorrhea remained significant after adjustment for sex but was attenuated after additional adjustment for previous medical visit before treatment.

CONCLUSIONS

Approximately 30% of children younger than 2 years with fUTI had associated symptoms. Respiratory symptoms were the most common associated symptoms and were associated with delayed antimicrobial treatment in age- and sex-adjusted analyses, although the association was attenuated after additional adjustment for previous medical visit before treatment.