Most common SBI, accounts for 5-8% of children presenting for fever without clear source
Associated with bacteremia in up to 30% of infants 4-8wk of age
E. coli is responsible for ~80% of UTIs
After 1yr of age, occult UTI with normal UA extremely rare
After 2yr of age, UTI remains common in girls (but associated with symptoms)
UTI in adolescent girl is suggestive of intercourse
Prevalence of UTI in bronchiolitis is only 0.8% based on 2019 meta-analysis, which is far lower than in previous studies, suggesting less need for automatic testing for UTI in bronchiolitis
Urinary tract infection 
Emergent
Pyelonephritis
Necrotizing Enterocolitis
Acute cystitis
Volvulus
Bladder trauma
Testicular torsion