kidney and urinary tract disorders
Urinary Tract Obstruction
Causes of Urinary Obstruction
Blockage may be partial or complete, affect one side or both sides, and develop rapidly (acutely) or slowly (chronically). The most common causes overall are In children: Structural abnormalities—for example, birth defects such as valves in the inside back part of the urethra (called posterior urethral valves—see Urethra Defects ) and other constrictions that narrow or block the ureter or urethra In young adults: None In older adults: Benign Prostatic Hyperplasia (BPH) (BPH) or Because BPH is so common in older men, obstruction is more common among men. Other common causes of obstruction include Urethral Stricture (narrowing caused by scar tissue) of the ureter or urethra that develop after radiation therapy, surgery, or procedures done on the urinary tract. The many other possible causes of urinary tract obstruction include the following: Polyps in the ureter Blood clot in the ureter Tumors in or near the ureter Disorders of the muscles or nerves in the ureter or bladder (such as due to drugs that have anticholinergic effects [see Anticholinergic: What Does It Mean? ], birth defects, or spinal cord injury) Formation of fibrous (scar) tissue in or around the ureter resulting from surgery, radiation therapy, or drugs (especially methysergide) Bulging of the lower end of the ureter into the bladder (ureterocele) Tumor, abscesses, and cysts of the bladder, cervix, uterus, prostate, or other pelvic organs A large mass of feces stuck in the rectum (rectal impaction) Hydronephrosis of both kidneys can occur during pregnancy as the enlarging uterus compresses the ureters. Hormonal changes during pregnancy may worsen the problem by reducing the muscular contractions that normally move urine down the ureters. This condition, commonly called hydronephrosis of pregnancy, usually resolves when the pregnancy ends, although the renal pelvis and ureters may remain somewhat distended afterward. 