Prompt diagnosis and treatment of this common condition is vital to relieve patient discomfort and hopefully reverse any associated decline in renal function.
Definition and classification
Acute retention (AR) is characterized by a sudden inability to void with associated suprapubic pain. Chronic retention (CR) is typically painless, and is subdivided into high or low pressure CR depending on the intravesical pressure at the end of micturition.
Incidence (including predisposition according to sex and geography)
The exact incidence is unknown but parallels the increasing incidence of benign prostatic hyperplasia (BPH) in the elderly male population. Approximately 10% of men in their forties and 90% of men in their eighties have detectable BPH. Studies have shown an approximate 10% risk of urinary retention in men with BPH. Retention of urine is relatively uncommon in females.
Commonest causes in males: benign prostatic hyperplasia, prostate cancer, urethral strictures and postoperative (secondary to drugs, immobility, constipation, pain and local oedema).
Commonest causes in females: retroverted gravid uterus, atrophic urethritis, fibroid uterus.
Other causes: faecal impaction, drugs (e.g. anti-cholinergics, alcohol, anti-histamines), blood clot (clot retention), urethral calculus, traumatic rupture of the urethra, infection (urethritis, prostatitis) and phimosis.
Pathogenesis (macro/microscopic pathology)
BPH occurs due to enlargement of glandular component of the transition zone of the prostate under the influence of the male hormone testosterone. This represents the commonest cause in men.
Symptoms and signs
In acute retention the patient classically presents with an inability to pass urine with suprapubic bladder discomfort.