Synonym: overactive bladder syndrome

Detrusor instability is characterised by uncontrolled contraction of the bladder wall (detrusor muscle), producing urgency, often with frequency and nocturia, and sometimes leakage (urge incontinence). See also separate article Urinary Incontinence. Detrusor instability can have a significant impact on quality of life.¹

Epidemiology

• Detrusor overactivity is the second most common cause of female urinary incontinence (stress incontinence is the most common).
• The prevalence of detrusor instability increases with age.²
• Detrusor overactivity may be associated with Parkinson's disease, spinal cord injury, diabetic neuropathy, multiple sclerosis, dementia or stroke; however, most cases have no specific cause.
• In men, urge incontinence may be due to neurological disease or an enlarged prostate (benign prostatic hypertrophy or prostate cancer).

Presentation

It usually presents with a sudden urge to urinate that is very difficult to delay and may be associated with leakage. Other features include:

• Frequency of micturition
• Nocturia
• Abdominal discomfort
• Urge incontinence

There are no specific physical signs and the diagnosis is usually made from the symptoms and confirmed with urodynamic studies.

Differential diagnosis

• Stress incontinence
• Functional incontinence
• Overflow incontinence
• Urinary fistula
• Enuresis
• Urinary tract infection
• Diabetes
• Bladder cancer
• Bladder stones

Investigations

• Urine dipstick analysis, and mid-stream urine specimen should be sent to the laboratory in order to rule out urinary tract infection.
• Investigations to consider differential diagnosis, e.g. blood tests for renal function tests, electrolytes, calcium, fasting glucose.
• Urodynamic studies show involuntary contraction of bladder during filling.
• Depending on the presentation, ultrasound of the renal tract and cystoscopy may be required.

Management

Current management options include bladder training, anticholinergic drugs, intravesical botulinum toxin injections, intermittent self-catheterisation and sacral or posterior tibial nerve stimulation. Primary care management for men with urge incontinence and overactive bladder syndrome is similar to that for affected women. Incontinence in adults which arises from detrusor instability is managed by combining drug therapy with conservative methods for managing urge incontinence, such as pelvic floor exercises and bladder training.³

The initial management in primary care includes providing advice on lifestyle changes, pelvic floor exercises and bladder training. Depending on the severity of symptoms and the level of distress, anticholinergic drugs may be started immediately or added if the initial advice is not totally effective.⁴ If these interventions fail then referral to secondary care for further assessment and management should be considered.⁵

Lifestyle changes⁶

• Trial of reduction in caffeine intake.
• Modification of high or low fluid intake. Some patients may cut back on the amount that they drink so that the bladder does not fill so quickly. However, this can make symptoms worse, as the urine becomes more concentrated, which may irritate the bladder muscle. Patients should aim to drink normal quantities of fluid per day (about 2 litres.)
• If body mass index is over 30, advise the patient to lose weight.

Bladder training

• This is first-line treatment and should be for a minimum of 6 weeks.
• It typically involves pelvic muscle training, scheduled voiding intervals with stepped increases, and suppression of urge with distraction or relaxation techniques.⁷

Drug treatment

• Anticholinergic drugs: anticholinergics (antimuscarinic drugs) - e.g. oxybutynin, propiverine, tolterodine, darifenacin, solifenacin, fesoterodine, trospium chloride - have a direct relaxant effect on urinary smooth muscle. They reduce involuntary detrusor contractions and increase bladder capacity. Anticholinergic drugs have been shown to improve symptoms in overactive bladder syndrome and allow a modest improvement in quality of life. It is not clear whether any benefits are sustained during long-term treatment or after treatment stops.⁸ There is no evidence of a clinically important difference in efficacy between antimuscarinic drugs. However, immediate-release non-proprietary oxybutynin is the most cost-effective of the available options.⁶
  • Immediate-release oxybutynin may be started if bladder training is not effective. It may also be used in conjunction with bladder training.
  • The efficacy and side-effects of tolterodine are comparable to those of modified-release oxybutynin. When choosing between oral immediate release oxybutynin or tolterodine, tolterodine may be preferable because of the reduced risk of dry mouth. Extended release preparations of oxybutynin or tolterodine might be preferred to immediate release preparations because there is less risk of dry mouth.⁹
  • Tolterodine is as effective in reducing leakage and other symptoms of an overactive bladder in patients with mixed incontinence as it is in patients with urge incontinence alone.¹⁰
  • If immediate-release oxybutynin is not well tolerated, darifenacin, solifenacin, tolterodine, propiverine, trospium, or an extended-release or transdermal formulation of oxybutynin should be considered as alternatives.⁶
  • The need for continuing anticholinergic drug therapy should be reviewed after 3-6 months.

• Other drug treatments:
  • Intravaginal oestrogens can be used to treat overactive bladder syndrome in postmenopausal women who have vaginal atrophy.
  • Injection of the bladder wall with botulinum toxin A may be used if there is idiopathic detrusor overactivity that has not responded to conservative treatment. However, this is outside UK marketing authorisation. A Cochrane review found that there were reports of the effectiveness of intravesical botulinum toxin but no significant study evidence of effectiveness relative to other treatments.¹¹

Nerve stimulation

• Sacral nerve stimulation is effective in treating symptoms of overactive bladder, including urinary urge incontinence, urgency and frequency in patients who do not respond to first-line treatments.¹²
• Percutaneous posterior tibial nerve stimulation (PTNS) is also effective in reducing symptoms in the short- and medium-term for patients with overactive bladder syndrome.¹³

Surgical treatment

• Surgery is only indicated for intractable and severe detrusor overactivity. Augmentation cystoplasty is the most frequently performed surgical procedure for severe urge incontinence.²
• In patients whose condition is refractory to nonsurgical treatment, open augmentation cystoplasty is an established procedure.
• Laparoscopic augmentation cystoplasty (including clam cystoplasty) is also indicated for overactive bladder syndrome. Potential advantages of a laparoscopic approach are less intraoperative blood loss, quicker recovery, less pain, a shorter stay in hospital and smaller scars.¹⁴
• Urinary diversion may be considered if augmentation cystoplasty is neither appropriate nor acceptable to the patient.

Complications

• May cause severe social difficulties, including undertaking shopping, and attending meetings, and therefore may also lead to social isolation and psychological difficulties.

Prognosis²

Behavioural therapy combined with drug treatment is often effective with up to 80% of cases improved and with excellent long-term results.

Document references

1. Coyne KS, Zhou Z, Thompson C, et al; The impact on health-related quality of life of stress, urge and mixed urinary incontinence.; BJU Int. 2003 Nov;92(7):731-5. [abstract]
2. Hussain AN et al; Overactive Bladder - Treatment, eMedicine, Aug 2009
3. Burgio KL, Goode PS, Locher JL, et al; Behavioral training with and without biofeedback in the treatment of urge incontinence in older women: a randomized controlled trial.; JAMA. 2002 Nov 13;288(18):2293-9. [abstract]
4. Thuroff JW, Abrams P, Andersson KE, et al; EAU Guidelines on Urinary Incontinence. Eur Urol. 2010 Nov 24. [abstract]
5. Management of urinary incontinence in primary care, Scottish Intercollegiate Guidelines Network (SIGN), 2005
6. Urinary incontinence: the management of urinary incontinence in women, NICE (2006)
7. Diokno AC, Burgio K, Fultz NH, et al; Medical and self-care practices reported by women with urinary incontinence. Am J Manag Care. 2004 Feb;10(2 Pt 1):69-78. [abstract]
8. Nabi G, Cody JD, Ellis G, et al; Anticholinergic drugs versus placebo for overactive bladder syndrome in adults. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD003781. [abstract]
9. Hay-Smith J, Herbison P, Ellis G, et al; Which anticholinergic drug for overactive bladder symptoms in adults.; Cochrane Database Syst Rev. 2005 Jul 20;(3):CD005429. [abstract]
10. Kreder KJ Jr, Brubaker L, Mainprize T; Tolterodine is equally effective in patients with mixed incontinence and those with urge incontinence alone.; BJU Int. 2003 Sep;92(4):418-21. [abstract]
11. Duthie J, Wilson DI, Herbison GP, et al; Botulinum toxin injections for adults with overactive bladder syndrome. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD005493. [abstract]
12. Sacral nerve stimulation for urge incontinence and urgency-frequency, NICE Interventional Procedure Guideline (2004)
13. Percutaneous posterior tibial nerve stimulation for overactive bladder syndrome, NICE Interventional Procedure Guideline (October 2010)
14. Laparoscopic augmentation cystoplasty (including clam cystoplasty), NICE Interventional Procedure Guideline (December 2009)

Acknowledgements