Abstract:Objective To explore the clinical characteristics of 3 cases of refractory urinary tract infection（UTI）in older pediatric patients without congenital urinary system malformations，and to provide diagnostic and therapeutic experience for clinical practice. Methods The clinical data of 3 complex refractory UTI patients without congenital urinary system malformations，admitted to the Department of Pediatric Renal Rheumatology and Immunology at Shengjing Hospital in 2021，presenting with recurrent fever and abnormal urination，were reviewed. In conjunction with literature guidelines，the relationship between complex UTI in older pediatric patients and bladder and bowel dysfunction（BBD）was summarized. Results None of the 3 patients had urinary system issues during infancy or early childhood；they all experienced constipation and began to exhibit recurrent UTI after the age of 3. No abnormaliy was found in lumbosacral MRI. Immunoglobulins，complements，and absolute lymphocyte counts were within normal ranges，and rheumatologic indicators such as neutrophil cytoplasmic antibodies and antinuclear antibodies showed no abnormalities. Urodynamic testing indicated the presence of overactive bladder and detrusor - sphincter dyssynergia.Anorectal manometry revealed low colonic motility，suggesting that the etiology of recurrent UTI in these patients may be related to BBD. Conclusion When older pediatric patients present with unexplained recurrent febrile urinary tract infections or abnormal urination，the possibility of complex UTI should be considered. Its etiology is not limited to urinary system malformations or immune deficiencies but also includes the potential presence of BBD，particularly when there is a history of defecation or urination abnormalities.