Transient ultrasonographic findings suggestive of vesicoureteral reflux associated with cystitis in pediatric and adolescent patients: Case reports and pathophysiological insights.

Although the clinical progression from lower to upper urinary tract infection is well recognized, the underlying pathophysiology remains understudied. Although vesicoureteral reflux is considered an important factor in pyelonephritis development, the mechanism underlying cases without reflux remains unclear. We report 2 pediatric and adolescent cases in which transient steepening of the ureteral jet angulation and bladder wall thickening were observed on ultrasonography during episodes of cystitis, with subsequent normalization after the resolution of inflammation. These findings suggest that cystitis-induced bladder wall thickening may transiently impair the antireflux mechanism and can provide a possible explanation for some cases of pyelonephritis without documented vesicoureteral reflux.