Urinary incontinence refers to the loss of control of urination. There are two types of urinary incontinence, urge incontinence and stress incontinence. Establishing the type of incontinence is essential, as this will determine the management.
Urge incontinence is caused by overactivity of the detrusor muscle of the bladder. Urge incontinence is also known as overactive bladder. The typical description is of suddenly feeling the urge to pass urine, having to rush to the bathroom and not arriving before urination occurs. Women with urge incontinence are very conscious about always having access to a toilet, and may avoid activities or places where they may not have easy access. This can have a significant impact on their quality of life, and stop them doing work and leisure activities.
The pelvic floor consists of a sling of muscles that support the contents of the pelvic. There are three canals through the centre of the female pelvic floor: the urethral, vaginal and rectal canals. When the muscles of the pelvic floor are weak, the canals become lax, and the organs are poorly supported within the pelvis.
Stress incontinence is due to weakness of the pelvic floor and sphincter muscles. This allows urine to leak at times of increased pressure on the bladder. The typical description of stress incontinence is urinary leakage when laughing, coughing or surprised.
Mixed incontinence refers to a combination of urge incontinence and stress incontinence. It is crucial to identify which of the two is having the more significant impact and address this first.
Overflow incontinence can occur when there is chronic urinary retention due to an obstruction to the outflow of urine. Chronic urinary retention results in an overflow of urine, and the incontinence occurs without the urge to pass urine. It can occur with anticholinergic medications, fibroids, pelvic tumours and neurological conditions such as multiple sclerosis, diabetic neuropathy and spinal cord injuries. Overflow incontinence is more common in men, and rare in women. Women with suspected overflow incontinence should be referred for urodynamic testing and specialist management.
Risk Factors for Urinary Incontinence
- Increased age
- Postmenopausal status
- Increase BMI
- Previous pregnancies and vaginal deliveries
- Pelvic organ prolapse
- Pelvic floor surgery
- Neurological conditions, such as multiple sclerosis
- Cognitive impairment and dementia
A medical history should distinguish between the types of incontinence. Try to differentiate between urinary leakage with coughing or sneezing (stress incontinence), and incontinence due to a sudden urge to pass urine with loss of control on the way to the toilet (urge incontinence).
Assess for modifiable lifestyle factors that can contribute to symptoms:
- Caffeine consumption
- Alcohol consumption
- Body mass index (BMI)
Assess the severity by asking about:
- Frequency of urination
- Frequency of incontinence
- Nighttime urination
- Use of pads and changes of clothing
Examination should assess the pelvic tone and examine for:
- Pelvic organ prolapse
- Atrophic vaginitis
- Urethral diverticulum
- Pelvic masses
During the examination, ask the patient to cough and watch for leakage from the urethra.
The strength of the pelvic muscle contractions can be assessed during a bimanual examination by asking the woman to squeeze against the examining fingers. This can be graded using the modified Oxford grading system:
- 0: No contraction
- 1: Faint contraction
- 2: Weak contraction
- 3: Moderate contraction with some resistance
- 4: Good contraction with resistance
- 5: Strong contraction, a firm squeeze and drawing inwards
A bladder diary should be completed, tracking fluid intake and episodes of urination and incontinence over at least three days. There should be a mix of work and leisure days.
Urine dipstick testing should be performed to assess for infection, microscopic haematuria and other pathology.
Post-void residual bladder volume should be measured using a bladder scan to assess for incomplete emptying.
Urodynamic testing can be used to investigate patients with urge incontinence not responding to first-line medical treatments, difficulties urinating, urinary retention, previous surgery or an unclear diagnosis. It is not always required where the diagnosis is possible based on the history and examination.
Urodynamic tests are a way of objectively assessing the presence and severity of urinary symptoms. Patients need to stop taking any anticholinergic and bladder related medications around five days before the tests.
A thin catheter is inserted into the bladder, and another into the rectum. These two catheters can measure the pressures in the bladder and rectum for comparison. The bladder is filled with liquid, and various outcome measures are taken:
- Cystometry measures the detrusor muscle contraction and pressure
- Uroflowmetry measures the flow rate
- Leak point pressure is the point at which the bladder pressure results in leakage of urine. The patient is asked to cough, move or jump when the bladder is filled to various capacities. This assesses for stress incontinence.
- Post-void residual bladder volume tests for incomplete emptying of the bladder
- Video urodynamic testing involves filling the bladder with contrast and taking xray images as the bladder is emptied. Theses are only performed where necessary and not a routine part of urodynamic testing.
The information here is adapted from the NICE guidelines from 2019 on urinary incontinence. Always check local and national guidelines before treating patients. The first step is to distinguish between urge and stress incontinence, as this dictates the management. Patients are usually managed in primary care initially and referred to a specialist MDT for further management where there are concerning features or an inadequate response to first-line treatment.
Management of Stress Incontinence
Management of stress incontinence involves:
- Avoiding caffeine, diuretics and overfilling of the bladder
- Avoid excessive or restricted fluid intake
- Weight loss (if appropriate)
- Supervised pelvic floor exercises for at least three months before considering surgery
- Duloxetine is an SNRI antidepressant used second line where surgery is less preferred
Pelvic floor exercises are used to strengthen the muscles of the pelvic floor. They increase the tone and improve the support for the bladder and bowel. Pelvic floor exercises should be supervised by an appropriate professional, such as a specialist nurse or physiotherapist. Women should aim for at least eight contractions, three times daily.
Surgical options to treat stress incontinence include:
- Tension-free vaginal tape (TVT) procedures involve a mesh sling looped under the urethra and up behind the pubic symphysis to the abdominal wall. This supports the urethra, reducing stress incontinence.
- Autologous sling procedures work similarly to TVT procedures but a strip of fascia from the patient’s abdominal wall is used rather than tape
- Colposuspension involves stitches connecting the anterior vaginal wall and the pubic symphysis, around the urethra, pulling the vaginal wall forwards and adding support to the urethra
- Intramural urethral bulking involves injections around the urethra to reduce the diameter and add support
Where the stress incontinence is caused by a neurological disorder or other surgical methods have failed, specialist centres may offer an operation to create an artificial urinary sphincter. This involves a pump inserted into the labia that inflates and deflates a cuff around the urethra, allowing women to control their continence manually.
Management of Urge Incontinence
Management of urge incontinence and overactive bladder involves:
- Bladder retraining (gradually increasing the time between voiding) for at least six weeks is first-line
- Anticholinergic medication, for example, oxybutynin, tolterodine and solifenacin
- Mirabegron is an alternative to anticholinergic medications
- Invasive procedures where medical treatment fails
Anticholinergic medications need to be used carefully, as they have anticholinergic side effects. These include dry mouth, dry eyes, urinary retention, constipation and postural hypotension. Importantly they can also lead to a cognitive decline, memory problems and worsening of dementia, which can be very problematic in older, more frail patients.
Mirabegron is used as an alternative medical treatment for urge incontinence with less of an anticholinergic burden. However, it is worth noting that mirabegron is contraindicated in uncontrolled hypertension. Blood pressure needs to be monitored regularly during treatment. It works as a beta-3 agonist, stimulating the sympathetic nervous system, leading to raised blood pressure. This can lead to a hypertensive crisis and an increased risk of TIA and stroke.
Invasive options for overactive bladder that has failed to respond to retraining and medical management include:
- Botulinum toxin type A injection into the bladder wall
- Percutaneous sacral nerve stimulation involves implanting a device in the back that stimulates the sacral nerves
- Augmentation cystoplasty involves using bowel tissue to enlarge the bladder
- Urinary diversion involves redirecting urinary flow to a urostomy on the abdomen
Last updated June 2020