Blockage anywhere in the urinary tract (for example, by stones or, in men, by prostate tumor Prostate Cancer Prostate cancer begins in a small area of the prostate gland, an organ found only in males. The risk of prostate cancer increases as men age. Symptoms, such as difficulty urinating, a need to... read more or urethral stricture Urethral Stricture A urethral stricture is scarring that narrows the urethra. A urethral stricture may be Present from birth Develop after an infection or injury A urethral stricture most commonly results from... read more )

Abnormal bladder function that prevents proper emptying, such as occurs in neurologic diseases (for example, spinal cord injury Spinal Injuries )

Structural abnormalities such as urethral diverticulum

Leaking of the valve-like mechanism between the ureter and the bladder, allowing urine and bacteria to flow backward from the bladder up the ureters, possibly reaching the kidneys (more common among children who have a UTI)

Insertion of a urinary catheter or any instrument by a doctor

Sexual intercourse

Use of a diaphragm with spermicide

Presence of an abnormal connection (fistula) between the vagina and the bladder or the intestine and the bladder

Among men, prostate enlargement Benign Prostatic Hyperplasia (BPH) Benign prostatic hyperplasia (BPH) is a noncancerous (benign) enlargement of the prostate gland that can make urination difficult. The prostate gland enlarges as men age. Men may have difficulty... read more or infection of the prostate Prostatitis Prostatitis is pain and swelling, inflammation, or both of the prostate gland. The cause is sometimes a bacterial infection. Pain can occur in the area between the scrotum and anus or in the... read more

Infection in the bloodstream ( septicemia Sepsis and Septic Shock Sepsis is a serious bodywide response to bacteremia or another infection plus malfunction or failure of an essential system in the body. Septic shock is life-threatening low blood pressure ... read more )

Infection of the heart valves ( infective endocarditis Infective Endocarditis Infective endocarditis is an infection of the lining of the heart (endocardium) and usually also of the heart valves. Infective endocarditis occurs when bacteria enter the bloodstream and travel... read more , an uncommon cause)