Hydroureter

Hydroureter is the dilation of the ureter, the tube that transports urine from the kidney to the bladder. It may occur alone or in combination with hydronephrosis, which is dilation of the renal pelvis and calyces. Hydroureter typically results from obstruction of urine flow proximal to the ureter or from vesicoureteral reflux.

Common causes include urolithiasis (stones) causing downstream obstruction, ureteropelvic junction obstruction, ureteral strictures, and extrinsic compression from tumors or pelvic masses. Neurogenic bladder, pregnancy, congenital anomalies, and postoperative strictures may also contribute. Obstruction or reflux elevates pressure in the ureter, leading to dilation and, with prolonged duration, potential damage to the renal unit.

Symptoms vary. Some individuals are asymptomatic; others experience flank or abdominal pain, colicky discomfort, urinary symptoms, or fever with infection. Diagnosis relies on imaging and renal function assessment. Ultrasound is usually the first test and can show a dilated ureter; CT urography or MR urography provides detailed anatomy and identifies the cause. Laboratory tests assess kidney function and identify infection.

Management targets the underlying cause and relief of obstruction. Options include ureteral stenting or percutaneous nephrostomy to decompress the system, and surgical reconstruction (eg, pyeloplasty for UPJ obstruction or ureteral reimplantation for distal obstruction). Stone removal may be required. In pregnancy, hydroureter can occur due to physiological dilation and is managed conservatively unless obstruction or infection develops. Prognosis depends on the duration and severity of obstruction and the success of treating the underlying cause.