Patent urachus and bladder outflow obstruction—chance or consequence? A study of a cohort of patients with complete patent urachus presenting to a tertiary urological center and a review of literature

Background To explore the association between patent urachus and bladder outflow obstruction (BOO). A retrospective review of patient records over a 35-year period (1983–2018) with complete patent urachus was performed. Antenatal ultrasound findings were noted, and postnatal investigations included ultrasound (US), micturating cystourethrogram (MCUG), functional nuclear medicine scans (MAG3, DTPA, and DMSA), and serum creatinine. Associated anomalies and management in all patients were analyzed. Results Sixty-six patients with all types of urachal remnants were identified of whom only 16 had a patent urachus. All presented clinically with a discharging umbilicus, 10/16 confirmed on MCUG and 4 had umbilical cord cysts on antenatal US. Twenty-five percent had associated bladder outlet obstruction (BOO): etiologies included atresia of posterior urethra, congenital urethral hypoplasia, urethral atresia with prune belly syndrome, and sacrococcygeal teratoma. Vesicoureteral reflux (VUR) was confirmed in 37%, and four of them had bladder outlet obstruction (BOO). Conclusion With patent urachus, bladder outflow obstruction occurs in the minority. Based on our findings, we commend US and cystogram to document VUR. The isolated PU should be treated nonoperatively up to a year of age. Renal function should be checked with the finding of VUR. The etiopathogenesis of the condition remains uncertain.