While it isn't common, the potentially life-threatening complication, called sepsis, can happen to infants, children, or adults. [verywellhealth.com]

[…] include: Frequent urinary tract infections Pyelonephritis Obstructive voiding symptoms Urinary retention Failure to thrive Hematuria Cyclic abdominal pain Urolithiasis Cobra head sign is seen in radiography In females: salpingitis, hydrosalpinx with sepsis [en.wikipedia.org]

Follow-Up Children were discharged within 48 h from surgery, except if severe UTIs or urinary sepsis were present at the hospital admission. [frontiersin.org]

Nevertheless, most urological investigators agree that endoscopic puncture of an ectopic ureterocele is indicated mainly for uncontrolled sepsis and azotaemia with BOO with or with no ureterocele prolapse. [onlinelibrary.wiley.com]

One study report on a boy with ureteroceles that obstructed the bladder outlet and ureters, who presented with sepsis and hyperammonemia despite normal liver function. [clinmedjournals.org]

There is no characteristic clinical picture caused by this condition, but fever, pyuria and recurrent abdominal pain are often present in children. [8] The main clinical presentation in this patient was recurrent abdominal pain. [wajradiology.org]

Symptoms can include: Frequent urinary tract infections Pyelonephritis Obstructive voiding symptoms Urinary retention Failure to thrive Hematuria Cyclic abdominal pain Urolithiasis Cobra head sign is seen in radiography In females: salpingitis, hydrosalpinx [en.wikipedia.org]

The outstanding symptoms are referable to pyuria, which appears in most cases. There may be abdominal or flank pain from the ureteric obstruction. [pediatrics.aappublications.org]

Her urinalysis with microscopy was positive for pyuria and bacteriuria. [ncbi.nlm.nih.gov]

Case 1 A 1-year-old boy presented in the casuality with high fever, altered sensorium, pyuria and in azotemia. He had a history of recurrent UTIs. On examination, his bladder was palpable and urine obtained on catheterization was full of pus cells. [jiaps.com]

There is no characteristic clinical picture caused by this condition, but fever, pyuria and recurrent abdominal pain are often present in children. [8] The main clinical presentation in this patient was recurrent abdominal pain. [wajradiology.org]

The entire urine specimen from patients with either flank pain and/or painful urination had pyuria, and a positive culture of bacteria was obtained in 80% percent of them. [archintsurg.org]