Urinary retention is the inability to empty the bladder. With chronic urinary retention, you may be able to urinate, but you have trouble starting a stream or emptying your bladder completely. You may urinate frequently; you may feel an urgent need to urinate but have little success when you get to the toilet; or you may feel you still have to go after you’ve finished urinating. With acute urinary retention, you can’t urinate at all, even though you have a full bladder. Acute urinary retention is a medical emergency requiring prompt action. Chronic urinary retention may not seem life threatening, but it can lead to serious problems and should also receive attention from a health professional.
Anyone can experience urinary retention, but it is most common in men in their fifties and sixties because of prostate enlargement. A woman may experience urinary retention if her bladder sags or moves out of the normal position, a condition called cystocele. The bladder can also sag or be pulled out of position by a sagging of the lower part of the colon, a condition called rectocele. Some people have urinary retention from rectoceles. People of all ages and both sexes can have nerve disease or nerve damage that interferes with bladder function.
What is the urinary tract?
The urinary tract consists of the organs, tubes, and muscles that work together to make, move, store, and release urine. The upper urinary tract includes the kidneys, which filter wastes and extra fluid from the blood, and the ureters, which carry urine from the kidneys to the bladder. The lower urinary tract includes the bladder, a balloon-shaped muscle that stores urine, and the urethra, a tube that carries urine from the bladder to the outside of the body during urination. If the urinary system is healthy, the bladder can hold up to 16 ounces-2 cups-of urine comfortably for 2 to 5 hours.
Muscles called sphincters squeeze shut the tubes from the bladder to help keep urine from leaking. The sphincter muscles close tightly like a rubber band around the opening of the bladder, which leads into the urethra. Nerves in the bladder tell you when it is time to urinate. As the bladder first fills with urine, you may notice a feeling that you need to go. The sensation to urinate becomes stronger as the bladder continues to fill. As it reaches its limit, nerves from the bladder send a message to the brain that the bladder is full and the urge to empty your bladder intensifies.
When you urinate, the brain signals the bladder muscle to tighten, squeezing urine out of the bladder. At the same time, the brain signals the sphincter muscles to relax. As these muscles relax, urine exits the bladder through the urethra. When all the signals occur in the correct order, normal urination occurs.
What causes urinary retention?
Urinary retention can be caused by an obstruction in the urinary tract or by nerve problems that interfere with signals between the brain and the bladder. If the nerves aren’t working properly, the brain may not get the message that the bladder is full. Even if you know that your bladder is full, the bladder muscle that squeezes urine out may not get the signal that it is time to push, or the sphincter muscles may not get the signal that it is time to relax. A weak bladder muscle can also cause retention.