What Is It?

Urinary tract infections involve the structures that produce urine and carry it out of the body. These structures include the kidneys, ureters, bladder and urethra. Urinary tract infections often are classified into two types based on their location in the urinary tract:

• Lower tract infections - These include cystitis (bladder infection) and urethritis (infection of the urethra). Lower urinary tract infections commonly are caused by intestinal bacteria, which enter and contaminate the urinary tract from below, usually by spreading from the skin to the urethra and then to the bladder. Urethritis also may be caused by microorganisms that are transmitted through sexual contact, including gonorrhea and chlamydia. Another form of male urinary infection is prostatitis, which is an inflammation of the prostate.

• Upper tract infections - These involve the ureters and kidneys and include pyelonephritis (kidney infection). Upper tract infections often occur because bacteria have traveled upward in the urinary tract from the bladder to the kidney or because bacteria carried in the bloodstream have collected in the kidney.

Although there are about 8 million cases of urinary tract infections each year in the United States, these infections are relatively rare in younger men. In men older than 50, the prostate gland (a gland near the bottom of the bladder, close to the urethra) can get larger and block the flow of urine from the bladder. This condition is known as benign prostatic hyperplasia, or BPH. This condition can prevent the bladder from emptying completely, which increases the likelihood that bacteria will grow and trigger an infection. Cystitis also is more common in men who practice anal intercourse and in those who are not circumcised. Other factors that increase the risk of urinary infections include an obstruction, such as that caused by a partial blockage of the urethra known as a stricture, and non-natural substances, such as rubber catheter tubes.

Symptoms

A urinary tract infection usually causes one or more of the following symptoms:

• Unusually frequent urination

• An intense urge to urinate

• Pain, discomfort or a burning sensation during urination

• Awakening from sleep to pass urine

• Pain, pressure or tenderness in the area of the bladder (midline, below the navel)

• Bedwetting in a person who usually had been dry at night

• Urine that looks cloudy or smells foul

• Fever, with or without chills

• Nausea and vomiting

• Pain in the side or upper back