obstruction
Chapter: 17
Blockade of a hollow viscus or blood vessel. Urinary obstruction can occur at the level of renal pelvis, ureter, ureterovesical junction, urinary bladder or the urethra. Such an obstruction may cause hydronephrosis, hydroureter and predispose to urinary infections. Obstructions can be congenital, due to developmental anomalies or acquired; bilateral or unilateral. Acquired obstruction of the ureters may be classified as extrinsic, if the ureter is compressed from outside or intrinsic if the lesion obstructs the lumen from inside. Typical extrinsic causes of obstruction are pelvic tumors, pregnant uterus, retroperitoneal fibrosis. Intrinsic causes include ureteric tumors, urinary stones, blood clots, detached renal papillae separated from the rest of the kidney by papillary necrosis. Obstruction of the bladder is most often caused by prostatic hyperplasia or urinary stones. Urethral strictures secondary to venereal inflammation or tumors are less common causes of urinary obstruction.