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Inability to Urinate (cont.)

What Are Risk Factors and Causes of an Inability to Urinate?

The two essential causes of urinary retention are

  1. blockage of the urethra, usually from benign enlargement of the prostate (BPH) and
  2. disruption of the delicate and complex system of nerves that connects the urinary tract with the brain and the nervous system (as described earlier).

Common Causes/Risk Factors

  • Blockage (obstruction): The most common cause of blockage of the urethra in men is enlargement of the prostate. In males, the prostate gland partially surrounds the urethra. If the prostate becomes enlarged, which is common in older men, it presses on the urethra and can block it. The most common cause of prostate enlargement is benign prostatic hypertrophy (often called BPH). Other causes of prostate enlargement include prostate cancer. Acute infection of the prostate (prostatitis) may also cause urinary retention. Causes of blockage of the urethra that can occur in both sexes include scar tissue (stricture), injury to the bladder outlet or urethra (as in a car wreck or bad fall), blood clots due to bladder infection or trauma, tumors in the pelvic region, and stones in the bladder outlet or urethra (rare).
  • Nerve problems: Disruption of the nerves between the bladder and the brain can cause you to lose control of your bladder function. The problem may lie in the nerves that send messages back and forth or in the nerves that control the muscles used in urination, or both. Some forms of this condition are referred to as neurogenic bladder. Occasionally, urinary retention is the first sign of spinal cord compression, a medical emergency that must be treated right away to prevent permanent, serious disability. The most common causes of this disruption include spinal cord injury, spinal cord tumor, strokes, diabetes mellitus, herniated or ruptured disk in the vertebral column of the back, or an infection or blood clot that places pressure on your spinal cord, and congenital spinal cord problems such as myelomeningocele (spina bifida) and tethered spinal cord. Nerve problems can also affect the ability of the muscles around the urethra to relax during urination, known as detrusor sphincter dyssynergia (DSD), which can lead to urinary retention.
  • Infection: An infection in the pelvic area, such as herpes, can interfere with nerves in the area. Inflammation and swelling caused by infections can also compress the urethra. Infections around the spinal cord can cause retention by placing pressure on the nerves of the spinal cord.
  • Surgery: Urinary retention is a relatively common problem after surgery. It can be a direct result of the anesthetic or the type of operation. Relative immobility after a surgery can also contribute to urinary retention. Previous bladder or prostate surgeries can sometimes cause urinary retention because of the formation of strictures (narrowing) due to scar tissue. This can occur after prostate cancer surgery as well as surgery for benign prostate enlargement (BPH).
  • Chronic overdistention of the bladder (holding one's urine for long periods of time) or excess alcohol intake can lead to urinary retention.
  • In women, problems with pelvic organ prolapse, (dropped bladder (cystocele), rectocele, prior surgery for urinary incontinence, gynecologic tumors, and cancer of the urethra may all cause urinary retention.
  • Bladder neck dysfunction (failure of the bladder outlet to open during urination) can cause urinary retention.
  • Other causes of transient urinary retention include immobility (especially post-operative), constipation, delirium, endocrine (hormone) problems, psychological problems, and prior instrumentation (medical procedures involving placing instruments in the urethra) of the urethra.

Medication-Related Causes

Certain medications can cause urinary retention, especially in men with prostate enlargement. Many of these medications are found in over-the-counter cold and allergy preparations.

  • Drugs that act to tighten the urinary channel and block the flow of urine include ephedrine (Kondon's Nasal, Pretz-D), pseudoephedrine (Actifed, Afrin, Drixoral, Sudafed, Triaminic), phenylpropanolamine (Acutrim, Dexatrim, Phenoxine, Prolamine), and amphetamines.
  • Antihistamines such as diphenhydramine (Benadryl, Compoz, Nytol, Sominex) and chlorpheniramine (Chlor-Trimeton, Allergy 8 Hr), as well as some older antidepressants, can relax the bladder too much and cause urination problems.
  • Anticholinergics, drugs that block the action of the neurotransmitter acetylcholine in the brain, that are used to treat a number of conditions
  • Cox-2 inhibitors, used for treating such conditions as sports injuries, arthritis, colorectal polyps, and menstrual cramps

Urinary Retention in Children

  • A child can have problems from birth that cause an inability to urinate properly. These problems usually become apparent within the first six months of life.
  • A child may suddenly become unwilling to urinate. This is generally due to a temporary condition that is causing pain with urination. Pain can be caused by a vaginal yeast infection in girls or an irritation from soap or shampoo used in bathing. Almost always, the child will eventually urinate without further help.
  • A history of sexual abuse also is associated with urinary retention.

Other Causes

Chronic urinary retention usually develops slowly because the bladder does not empty completely. It may take a very long time to be diagnosed because you may not have any symptoms.

  • A weak bladder muscle, chronic obstruction, and nerve diseases or injury all can contribute to chronic urinary retention.
  • Chronic retention can lead to urinary incontinence (the unwanted leakage of urine from the bladder), urinary tract infection, and kidney failure.
  • Prolonged immobility can increase the risk of urinary retention.
Medically Reviewed by a Doctor on 10/27/2016
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