Urinary retention

Urinary retention also known as ischuria is a lack of ability to urinate. It is a common complication of benign prostatic hypertrophy (also known as benign prostatic hyperplasia or BPH), although anticholinergics may also play a role, and requires a catheter or Prostatic stent. Various medications (e.g. some antidepressants) and recreational use of amphetamines and opiates are notorious for this.

Signs and symptoms

Urinary retention is characterised by poor urinary stream with intermittance, straining, a sense of incomplete voiding and urgency. As the bladder remains full, it may lead to incontinence, nocturia (need to urinate at night) and high frequency. Retention is a medical emergency, as the bladder may distend (stretch) to enormous sizes and possibly tear if not dealt with quickly. If the bladder distends enough it will begin to become painful. The water can also pass back up the ureters and get into the kidneys, causing kidney failure. A person should go straight to an emergency department as soon as possible if unable to urinate when having a painfully full bladder.

In the longer term, obstruction of the urinary tract may cause:

• Bladder stones
• Loss of detrusor muscle tone (atonic bladder is an extreme form)
• Hydronephrosis (congestion of the kidneys)
• Hypertrophy of detrusor muscle
• Diverticula in the bladder wall (leads to stones and infection)

Causes

• Benign prostatic hypertrophy
• Prostate cancer and other pelvic malignancies
• Congenital urtheral valve abnormalities
• Detrusor muscle dyssynergia
• Circumcision
• Damage to the bladder
• Obstruction in the urethra, for example a metastasis or a precipitated pseudogout crystal in the urine
• Paruresis ("shy bladder syndrome")- in extreme cases, urinary retention can result
• Consumption of some psychoactive substances, mainly stimulants, such as Ecstasy.
• Use of drugs with anticholinergic properties.

Diagnostic tests

Uroflowmetry may aid in establishing the type of micturition abnormality. A post-void residual scan may show the amount of urine retained. Determination of the serum prostate-specific antigen (PSA) may aid in diagnosing or ruling out prostate cancer. Urea and creatinine determinations may be necessary to rule out backflow kidney damage.

Treatment

In acute urinary retention, urinary catheterization, placement of a Prostatic stent or suprapubic cystostomy instantly relieves the retention. In the longer term, treatment depends on the cause. Benign prostatic hypertrophy may respond to alpha blocker and 5-alpha-reductase inhibitor therapy, or surgically with prostatectomy or transurethral resection of the prostate (TURP).

See also

• Constipation, inability to defecate
• Urinary incontinence, inability to hold the urine

References