Chronic Urinary Retention

See also: Benign prostatic hyperplasia, urinary tract obstruction, lower urinary tract symptoms in men, lower urinary tract symptoms in women, voiding difficulties.

The most usual cause of chronic urinary retention is bladder outlet obstruction, the main causes of which are listed below:

• This is largely a condition that affects men as its commonest cause is BPH, but there is an appreciable background incidence in women.
• There are few figures available for the population at large, most studies examining defined clinical populations. Surveys of older men (usually aged>60) usually arrive at a figure of a prevalence of lower urinary tract symptoms of 25–30%.¹
• Of those patients in the community with moderate to severe symptoms of urinary obstruction, up to 60% do not seek medical help and simply put up with the problem.¹
• Depending on definitions, benign prostatic hyperplasia is thought to affect 10–30% of men in their seventies.²

Symptoms

The symptoms, if any are present, usually come on slowly and may not be noticed due to their gradual evolution. The commoner ones are listed below:

• Urinary frequency
• Urinary urgency
• Urinary hesitancy
• Poor urinary stream
• Post-micturition dribbling
• Nocturia
• Nocturnal enuresis
• Urinary incontinence
• A sensation of incomplete voiding after micturition
• 'Double' or recurrent voiding of urine (returning to micturition due to a sensation of 'needing to go again')
• Symptoms consistent with urinary tract infection
• Lower abdominal discomfort/restlessness may indicate intermittent acute-on-chronic-retention
• Acute urinary retention
• Severe obstructive uropathy can cause renal failure due to back pressure and so may cause lethargy, pruritus, recurrent infections, hypertension etc.

Signs

• Check blood pressure – ? reason to suspect renal impairment.
• Patients with long-standing significant urinary retention may have a palpable enlarged bladder, which will usually be non-tender.
• Check for enlargement of kidneys via bimanual palpation.
• Digital rectal examination should be carried out to look for evidence of prostatomegaly and any signs of prostatic carcinoma.
• Examine external genitalia in children, men and women to seek evidence of urethral abnormalities causing urinary flow obstruction, e.g. urethral stricture, phimosis, meatal stenosis.

A vast range of conditions can cause chronic urinary retention, outlined and categorised at the head of the document. Impaired emptying of the bladder due to dysfunction of the bladder muscle or its innervation is the major alternative cause of the symptoms outlined above.³

• Urinalysis should be carried out to look for evidence of glycosuria, infection, proteinuria or haematuria.
• MSU for urine microscopy and culture.
• Check U&Es/creatinine to seek evidence of renal failure; they can be normal even in significant renal impairment so consider using estimated GFR calculator (abbreviated MDRD calculation) or checking creatinine clearance by 24-hour urinary collection.
• Check FBC to exclude anaemia of chronic renal failure or raised white cell count due to infection.
• Blood glucose should be checked if diabetes may be causing an osmotic diuresis and thus leading to lower urinary tract symptoms.
• Prostate Specific Antigen (PSA) should be considered in patients aged >70 years or where there is a clinical suspicion of prostate cancer after digital rectal examination/on basis of symptoms such as backache.
• There is controversy over PSA's usefulness as a screening investigation,⁴ and current consensual best practice is to counsel anyone having the test as to the potential consequences of an abnormal result, and current uncertainties about optimal management in the case of an abnormal result.⁵For asymptomatic individuals or those with uncomplicated lower urinary tract symptoms it is acceptable to omit PSA testing.⁵
• Many further investigations may be used in secondary care to investigate the severity of urinary flow disruption and to establish the underlying cause. These include:
  • Urinary tract ultrasound (including prostatic US performed transrectally ± prostatic biopsy)
  • MRI or CT imaging of urinary tract
  • Intravenous pyelography ± post-voiding imaging of residual urine volume
  • Post-voiding residual volume determination through catheterisation
  • Renal radionuclide scanning.

• A useful way of classifying the severity of patient symptoms (and deciding on the degree of intervention necessary to improve them) is use of the International Prostate Symptom Score (IPSS).
• It is a well-validated measure of symptom severity but does not necessarily correlate with the severity of the causative pathology (particularly for benign prostatic hyperplasia).⁶
• It appears that other factors than the reduction in urinary flow rates influence the likelihood of symptoms bothering a patient and of their presenting to a doctor.⁶

• In the absence of a palpable bladder, with no evidence of a distal cause such as phimosis or urethral stricture, with normal initial investigations, IPSS ≤7, and/or in patients who would not consider surgical intervention:
  • Stop any precipitating medications
  • General lifestyle advice
  • Fluid intake and avoiding evening drinking
  • Alcohol intake
  • Tea and coffee intake
  • Being prepared re access to toileting facilities
  • Bladder retraining and regular voiding
  • Consider use of alpha-blockers such as tamsulosin (although very little evidence of significant 'real-world' effectiveness in primary care)⁷
  • Consider use of 5-alpha-reductase inhibitors (e.g. finasteride) to prevent progression of symptoms due to prostatic hyperplasia.⁸
  • There is some evidence that combination therapy with alpha-blockers and 5-alpha-reductase inhibitors reduces the likelihood of acute urinary retention or progression to the need for surgery in cases of benign prostatic hyperplasia in a 'real-life' setting.⁹
  • Saw palmetto extract (phytotherapy with Serenoa repens) appears to be comparably effective to tamsulosin.¹⁰
• If abnormality in U&E/creatinine/estimated GFR/rectal examination/urinalysis/MSU/history of episodes of acute urinary retention/significantly elevated PSA, patient agreeable for surgery ± medical therapy/IPSS ≥7:
  • Consider medical therapy with alpha-blockers/5-alpha reductase inhibitors.
  • Referral to local urology services for further assessment.
• If episodes of acute urinary retention, palpable bladder, significantly elevated PSA or abnormality in U&E:
  • Refer urgently to local urology services.

Useful surgical therapies include:

• Transurethral resection of prostate (TURP)
• Transurethral microwave therapy (TUMT)
• Transurethral needle ablation (TUNA)

• Acute retention of urine
• Obstructive uropathy due to chronic back pressure on kidneys causing renal impairment
• Urinary incontinence due to overflow

This is highly variable depending on the underlying cause. In benign prostatic hyperplasia the norm is progression of the symptoms, but there is considerable variability in symptoms over time and some patients experience permanent or transient improvement. Acute urinary retention rates in BPH are ~1–2% per year.²