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

Urinary retention is the inability to empty the bladder. Chronic urinary retention is frequently asymptomatic - a patient is able to urinate, but may experience lower urinary tract symptoms (LUTs), related to storage and voiding difficulties. This is contrast to acute urinary retention which is painful and the patient is unable to urinate despite a full bladder. Acute urinary retention is a medical emergency. Chronic urinary retention, whilst not immediately life threatening, can lead to hydronephrosis and renal impairment and puts the patient at risk of acute-on-chronic retention, so requires diagnosis and treatment.

The most usual cause of chronic urinary retention is bladder outlet obstruction.

• This is largely a condition that affects men as its commonest cause is BPH, but there is an appreciable background incidence in women.
• Experience of urinary storage or voiding-related symptoms are very common in middle-aged to older men. However, as they increase in severity, they have a significantly negative effect on quality of life. Over 40% of men aged 50 years or more have moderate to severe LUTs but many do not seek medical help and simply put up with the problem. Only 18% have a diagnosis of BPH.³
• The cause of urinary retention in women is unknown in about a third of cases but approximately half are due to Fowler's syndrome (typically seen in women in their 20s-30s and thought to be due to failure of the urethral sphincter to relax appropriately).⁴

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
• New onset 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
• Increasing lower abdominal discomfort (may indicate intermittent acute-on-chronic-retention)
• Acute urinary retention
• Lethargy, pruritus, recurrent infections, hypertension due to renal failure (rare with cases of mild to moderate obstructive uropathy)

Signs

• Check blood pressure as possible indicator of renal impairment.
• Abdominal and genito-urinary examination:
  • 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.
• Neurological examination should exclude cord compression and look for evidence of other relevant neurological conditions.

A vast range of conditions can cause chronic urinary retention, most commonly via preventing bladder outflow (see above). Additional causes of impaired emptying of the bladder are due to dysfunction of the bladder muscle or its innervation.⁵

• Urinalysis - look for evidence of glycosuria, infection, proteinuria or haematuria.
• MSU for urine microscopy and culture.
• Blood tests:
  • 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.
  • 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,⁶ 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.⁷ For asymptomatic individuals or those with uncomplicated lower urinary tract symptoms it is acceptable to omit PSA testing.⁷
• Voiding diaries.
• 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
  • Post-voiding residual volume determination through catheterisation (the definition of a significant post-void residual urine remains debatable)⁸
  • Urodynamic studies (uroflowmetry, cystometry)
  • Intravenous pyelography ± post-voiding imaging of residual urine volume
  • 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).⁹
• Response to the quality of life question in the IPSS ('If you were to spend the rest of your life with your urinary condition the way it is now, how would you feel about that?') is a strong predictor for determining if interventions are indicated.³

1. Where there is:
   • No palpable bladder
   • No evidence of a distal cause of obstruction such as phimosis or urethral stricture
   • Normal initial investigations
   • IPSS ≤7
   • A patient who does not wish to consider surgical intervention
   Appropriate management includes:
   • Stop any precipitating/aggravating medication.
   • General lifestyle advice such as:
     • Regulating fluid intake and avoiding evening drinking
     • Reducing alcohol intake
     • Reducing tea and coffee intake
     • Preparation enabling access to toileting facilities
   • Use of bladder retraining and regular voiding.
   • Drug therapy:
     • Alpha-blockers, such as tamsulosin. Note, there is very limited evidence of significant 'real-world' effectiveness for their use in primary care.¹⁰
     • 5-alpha-reductase inhibitors, such as finasteride, to prevent progression of symptoms due to prostatic hyperplasia.¹¹
     • 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.¹²
     • Saw palmetto extract (phytotherapy with Serenoa repens) appears to be comparably effective to tamsulosin.¹³
2. Where there is:
   • Abnormal U&Es/creatinine/eGFR
   • Abnormal rectal examination
   • Abnormal urinalysis or MSU
   • History of episodes of acute urinary retention
   • Significantly elevated PSA
   • A patient requesting surgery in addition to, or in place, of medical therapy
   • IPSS ≥7
   Management should include:
   • Consider/optimise medical therapy with alpha-blockers/5-alpha reductase inhibitors.
   • Referral to local urology services for further assessment.
   • Useful surgical therapies include:
     • Transurethral resection of prostate (TURP)
     • Transurethral microwave therapy (TUMT)
     • Transurethral needle ablation (TUNA)

• Acute retention of urine
• Hypertrophy of detrusor muscle and diverticula formation
• Hydronephrosis due to chronic back pressure on kidneys, ultimately resulting in renal impairment
• Urinary incontinence due to overflow

This is highly variable depending on the underlying cause.

In BPH, the general trend is for symptoms to worsen over time. However, there is considerable variability and some patients experience permanent or transient improvement. Only about 14% of men with moderate to severe symptoms had clinically noticeable worsening of their symptoms during five years of follow-up. In one large trial of men with BPH and moderate to severe baseline symptoms, only 6% of men on placebo experienced acute urinary retention or needed BPH surgery after five years and none developed renal insufficiency.¹⁵