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Next Lesson - Glomerular Disease
Core
Urinary incontinence (UI) is defined as the complaint of any involuntary leakage of urine. This can have a huge impact on a person’s quality of life through social exclusion and a sense of shame. Despite this, many patients “just put up” with urinary incontinence without seeking medical help, as it is seen as “a normal part of ageing”.
There are four types of urinary incontinence:
- Stress Urinary Incontinence (SUI) – the complaint of involuntary leakage on increased abdominal pressure, such as exertion, sneezing or coughing.
- Urge Urinary Incontinence (UUI) – the complaint of involuntary leakage accompanied by or proceeded by the urge to initiate voiding.
- Mixed Urinary Incontinence (MUI) – the complaint of involuntary leakage associated with urgency, and also with exertion, effort, sneezing, or coughing.
- Overflow Incontinence – the complaint of involuntary leakage associated with the bladder being overly full, either due to detrusor weakness or blockage, with no urge to micturate.
The prevalence of UI increases with age, and SUI is the most common subtype. A history is the most important investigation when determining the type of urinary incontinence present in a patient.
The three most important risk factors for developing UI are: pregnancy & childbirth, pelvic prolapse, and menopause, as such UI is more common in females.
Some other risk factors for UI include:
- Race
- Family predisposition
- Anatomical abnormalities
- Neurological abnormalities
- Obesity
- Increasing age
- Increased intra-abdominal pressure
- Cognitive impairment
- UTIs
- Drugs
- Pelvic surgery
Lower Urinary Tract Symptoms (LUTS)
LUTS may be associated with urge urinary incontinence.
LUTS can be classified into three types based on which part of the micturition process they are associated with storage, voiding, and post-micturition. The table below shows the symptoms associated with each type of LUTS.
Table - Three types of lower urinary tract symptoms
The types of LUTS experienced can give clues about the underlying diagnosis, and can be seen in other conditions, not just UI. For example, hesitancy can be a symptom of Benign Prostatic Hyperplasia (BPH) – due to the enlarged prostate a greater intra-vesical pressure is needed to void the bladder, this pressure takes time to build up so will manifest as hesitancy to begin voiding.
A thorough history is key when a patient presents with UI as this can be helpful in categorising the type of UI the patient is experiencing. For example, a sudden urge preceding the incontinence is typical of urge incontinence, whereas leakage on coughing is typical of stress incontinence.
An examination of a patient should include measurement of their BMI, an abdominal examination with particular attention paid to trying to palpate a full bladder, a Digital Rectal Examination (DRE) (to quickly assess for any neurological deficit in any patient, and to check for prostate enlargement in males), and for females an examination of the external genitalia and a vaginal examination should also be performed.
All patients should receive a urine dipstick in order to rule out a urinary tract infection, and to also check for haematuria, proteinuria, and glycosuria, any of which would indicate an underlying pathology.
Basic, non-invasive urodynamics can be done such as a frequency-volume chart, asking the patient to keep a bladder diary, and recording the patient’s post-micturition residual volume. These can all be performed between general practice appointments, as no specific secondary care need exists without these.
Further optional investigations could include invasive urodynamics (like pressure-flow studies in which a computer measures the patient’s abdominal and vesical pressure to calculate the detrusor pressure), pad tests (wherein a patient takes an agent to colour their urine and then wears a pad for a period of time to determine if the fluid they are leaking is actually urine), or cystoscopy (direct visualisation of the patient’s bladder).
The management of UI depends on the symptoms the patient is experiencing, the degree of bother the symptoms are causing the patient, the effect the treatment will have on the patient’s symptoms, and any previous or current treatments the patient may have had. In any case, the management plan should be individualised and based on a systematic approach.
A conservative approach to the treatment of any form of UI is based around lifestyle modifications. Patients should be encouraged to modify their fluid intake, lose weight, and stop smoking (if applicable). Modification to fluid intake should be explained carefully to the patient: they should still be drinking the same volume, but earlier in the day, as dehydration creates more concentrated urine, which can further irritate the bladder.
Avoiding constipation has been shown to also be helpful in the treatment of UI. Patients can also undergo bladder training, where they should aim to only void at certain times of the day in the hopes that this fixed voiding schedule will help their UI.
Decreasing caffeine and alcohol intake has been shown to be useful in the treatment of UUI.
Contained incontinence is a form of therapy which does not aim to treat the cause of the UI, but to collect the leaked urine and allow for disposal at a time that is convenient. This is generally used for patients who are unsuitable for surgery or have failed conservative or medical management.
This can be done in the form of an indwelling catheter (a catheter which is put in place and can be left in long-term). These can be inserted through the urethra or if this is too difficult, above the pubic bone (suprapubic catheter) – however suprapubic catheters require a full bladder at the time of insertion and are related to an increased mortality if the bowel is damaged in the insertion.
Other forms of contained incontinence devices are sheath devices, essentially an adhesive condom attached to catheter tubing and a bag, or incontinence pads.
Diagram - Placement of a suprapubic catheter in a female
Creative commons source by BruceBlaus [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
Initially, patients presenting with stress incontinence should be encouraged to carry out pelvic floor muscle training. These exercises consist of eight contractions of the pelvic floor, three times a day. This should be done for at least three months before reassessing the patient, and if the patient is struggling, a referral to specialist physiotherapists can be made.
Duloxetine is an option for the pharmacological management of SUI. It is a combined noradrenaline and serotonin uptake inhibitor. This increases activity in the striated muscle portion of the urinary sphincter during the filling phase of the bladder. This is not recommended by NICE as a first-line or routine second-line treatment, but it can be offered as an alternative to surgery if this is the patient’s preferred choice.
Surgical options differ for males and females. For females, choices for surgery are offered around the patient’s intent to have future pregnancies.
Low-tension vaginal tapes are the most common surgical procedure for the permanent treatment of SUI. Depending on the clinician's choice, these can consist of a polypropylene mesh, or another material, which helps to support the mid-urethra. This can be placed using minimally invasive techniques and has a long-term success rate of 60-70% (source). There is a controversy with certain types of mesh, but this is beyond the scope of this article.
Retropubic suspension procedures aim to correct the anatomical position of the proximal urethra and improve urethral support. This is similar to a classical fascial sling procedure which helps support the urethra and encourages bladder outflow resistance.
Intramural bulking agents are used in patients who may want to have a future pregnancy. As such, this is a temporary measure to treat SUI. Injections of substances such as silicone or collagen are placed into the bladder neck under general or local anaesthetic. This improves the ability of the urethra to resist abdominal pressure.
For males, the gold standard surgical treatment is an artificial urinary sphincter. These help correct sphincter deficiencies caused by neurological damage or surgery. A cuff is placed around the normal sphincter and stimulates the contraction of the urethra. This can be opened and closed by the patient at will through a hydraulic system. Another option for males is a male sling procedure.
Diagram - An artificial urinary sphincter
Creative commons source by BruceBlaus [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
The first-line treatment for UUI is bladder training. This consists of a voiding schedule, initially every hour of the day, to train the bladder out of producing the urge. The patient must not void in between, even if this means there is some leaking. Intervals are increased by 15-30 minutes a week until an interval of 2-3 hours is reached. This must be tried for 6 weeks.
The first option for pharmacological treatment of UUI are anticholinergics like Oxybutynin. These act on M2 and M3 muscarinic receptors. Side effects of Oxybutynin are related to the effects on muscarinic receptors found at other sites in the body, such as dry mouth, dry eyes and constipation.
Mirabegron, a beta-3-adrenoceptor agonist can also be used in the pharmacological therapy of SUI. This drug increases the bladder’s capacity to store urine.
If anticholinergics and beta-3-agonists fail to help the patient, an intravesical injection of Botulinum toxin (Botox) can be given. This is a potent biological neurotoxin which inhibits the release of acetylcholine at the pre-synaptic neuromuscular junction causing paralysis of the detrusor muscle. This is done under local or general anaesthetic. It has a duration of action of 3-6 months.
If pharmacological management fails, there are surgical options. These include sacral nerve modulation, augmentation cystoplasty, and urinary diversion, but these are rare.
Edited by: Dr. Maddie Swannack
Reviewed by: Dr. Thomas Burnell
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