Frequency and characteristics of seizures precipitated by febrile urinary tract infections in neonates and infants.

Background: A febrile urinary tract infection (UTI) is a minor febrile seizure (FS) determinant. Seizures precipitated by febrile UTIs in neonates and infants frequently surprise parents, as they are vulnerable to bacterial meningitis and younger than the usual ages of FS. However, their frequency and characteristics are relatively unknown.

Methods: This study screened 1059 children (≤12 months) with febrile UTIs admitted to Chonnam National University Children's Hospital from January 2015 to June 2023. Patients with seizures precipitated by febrile UTIs were enrolled, and their medical records were reviewed. The frequency and clinical characteristics of seizures effectuated by febrile UTIs were investigated by comparing FS, FS+, and afebrile seizure (aFS).

Results: Twenty-eight patients (2.6%) were enrolled: 19 with early-onset FS+ (2.3% of 814 patients <6 months), nine with FS (3.7% of 245 patients), but there were none with aFS. Acute pyelonephritis was found in 80.8% of 26 patients. Clustered seizures (47.4% vs. 22.2% in FS, P = 0.197) and complex types (73.7% vs. 22.2%; P = 0.015) were frequent in early-onset FS+. Among 42 seizure episodes, bilateral tonic seizures were noted only in FS+ (44.8%; P = 0.001), but bilateral tonic-clonic seizures were frequent in FS (69.2% vs. 27.6%; P = 0.011).

Conclusion: Seizures precipitated by febrile UTIs occurred in 2.6% of neonates and infants: all were febrile and were predominantly with acute pyelonephritis. Infantile FS characteristics of febrile UTIs resembled those of usual FS, whereas early-onset FS + differed significantly as usually occurring in complex types and bilateral tonic ones.