Ureteral Obstruction

 Pathophysiology

Ureteral Obstruction is structural or functional hindrance of normal urine flow, sometimes leading to renal dysfunction (obstructive nephropathy). Ureteral obstruction can be classified as intraluminal or extraluminal. Intraluminal causes include kidney stones, blood clots and scarring; these conditions usually cause unilateral obstruction and Extraluminal causes include several conditions related to enlarged masses that place pressure on the ureter and create obstructions.

 Disease statistics

In large surveys of elderly men a prevalence of 20-35% has been estimated for symptoms of urinary obstruction. Post-mortem examinations have found hydronephrosis in 3.8% of adults and 2.0% of children. Obstructive uropathy associated with congenital anomalies of the urinary tract accounts for 30-50% of all end stage renal disease cases in children. In women, obstruction is more likely to occur at a younger age as a result of pregnancy or uterine cancer.

 Disease treatment

Stents or drains placed in the ureter or in a part of the kidney called the renal pelvis may provide short-term relief of symptoms. Long-term relief from obstructive uropathy requires surgery. A Foley catheter, placed through the urethra into the bladder, may also be helpful.

 Major research

99mTc-DTPA is one of the most widely used radiopharmaceuticals to assess renal function of patients with suspected urinary obstruction, with excretion predominantly by glomerular filtration. Renal scintigraphy was preferentially used because it is a noninvasive and quick exam, providing rapid dynamic imaging of the kidneys, including renal flow, function, and urinary outflow evaluation.