25th July 2023

Continence

Overview

Continence is the ability to control one’s bladder and bowel. This topic will mainly focus on urinary incontinence in the elderly. Urinary incontinence is defined as the involuntary leakage of urine and can be classified as below.

• Functional incontinence: inability to reach the toilet in time due to poor mobility and/or unfamiliar surroundings.
• Stress incontinence: secondary to exertion or effort/sneezing/coughing/laughing. The bladder sphincter is incompetent and can be associated with genitourinary prolapse.
• Urge incontinence: associated with or immediately preceded by the urge to urinate. Urgency can be defined as the sudden and strong desire to urinate that cannot be deferred. It is because of detrusor instability or hyperreflexia, which leads to involuntary detrusor contraction. This may be idiopathic or secondary to neurological conditions such as multiple sclerosis, Alzheimer’s dementia, spinal cord injury and Parkinson’s disease. It can also be caused by infection or bladder stones which cause local irritation.
• Overactive bladder (OAB) syndrome: a condition that causes urgency either with or without incontinence. It is caused by detrusor overactivity.
• Mixed incontinence: a combination of urge and stress incontinence.
• Overflow incontinence: urinary leakage due to either detrusor underactivity or chronic bladder outflow obstruction (BOO). Both can cause urinary retention and subsequent leakage. BOO is often due to prostate problems in men, which can lead to obstructive nephropathy secondary to back pressure.
• True incontinence: a fistula forms between the vagina and the ureter or bladder or urethra and predisposes to continuous urine leakage.

Urinary incontinence is more prevalent with age and is common in those living in institutions such as assisted living and care homes. Risk factors include high BMI, diabetes mellitus, pregnancy and childbirth, hysterectomy, multiparity, recurrent UTI, cognitive impairment, neurological disorders, and prostate disorders.

Assessment/Investigations

• Review medications as a possible cause for symptoms.
• Assess lifestyle factors, i.e., alcohol/caffeine intake, weight.
• Assess functional status, i.e., ability to access the toilet.
• Men: perform a digital rectal examination to assess the prostate and to rule out any other rectal pathology.
• Women: take a full obstetric history. Perform a vaginal/bimanual examination to exclude pelvic organ prolapse and assess the ability to initiate voluntary contraction of pelvic floor muscles, i.e., Kegel’s exercise.
• Urine dip and culture.
• Bladder diary/chart to be recorded by the patient (minimum 3 days).
• Urodynamic studies.
• Imaging: bladder scan (to assess post void residual volume to rule out voiding dysfunction). Ultrasound kidney ureter bladder is indicated in men and women with neurological conditions such as spina bifida/spinal cord injury, where renal complications may occur.

It is important to note that urinary incontinence associated with features suggestive of urological/gynaecological cancer should be referred via the two-week wait pathway. Symptoms to exclude:

• Men: lower urinary tract symptoms complicated with recurrent/persistent UTI, retention, renal impairment, persisting bladder or urethral pain and associated faecal incontinence.
• Women: constant leakage (possible urogenital fistula), previous pelvic radiation therapy, associated faecal incontinence, persisting bladder or urethral pain and pelvic masses.

Management

If stress incontinence is predominant:

• Pelvic floor muscle training: minimum 8 contractions performed 3 times/day for a minimum of 3 months. Continue if successful. Electrical stimulation and/or biofeedback in women who cannot actively contract pelvic floor muscles.
• Surgical treatment if conservative measures fail, i.e., open colposuspension or autologous rectus fascial sling.
• Duloxetine is used second line in women who do not want or are not surgical candidates. It increases the synaptic concentration of noradrenaline and serotonin within the pudendal nerve. This increases the stimulation of urethral sphincter striated muscles and enhances contraction.

If urge incontinence is predominant:

• Bladder retraining: minimum of 6 weeks involving pelvic muscle training, scheduled voiding intervals with stepped increases and suppression of urge with distraction or relaxation techniques.
• If bladder training alone is ineffective, antimuscarinics/anticholinergics can be offered as an adjunct, e.g., oxybutynin, tolterodine, solifenacin, and fesoterodine. They act by having a direct relaxant effect on urinary smooth muscle. Hence involuntary detrusor contractions are reduced, and bladder capacity is increased. Immediate-release formulations are more cost effective. However, extended-release formulations are associated with fewer side effects, such as dry mouth. Avoid these drugs in frail elderly women. An alternative is mirabegron – a beta-3 agonist of detrusor smooth muscle which promotes detrusor relaxation. It is avoided in patients with uncontrolled hypertension.
• Other treatment options include botulinum toxin injections.

In mixed incontinence, management is directed at the more predominant symptom; however, a combination of strategies can be used.

• Pelvic floor muscle training and bladder retraining are first line treatment.
• Drug treatment such as oxybutynin is the first line, but all antimuscarinics are equally effective. Oxybutynin should be avoided in the elderly as it impairs cognition. Newer antimuscarinics such as darifenacin, solifenacin, tolterodine and trospium are alternatives. Extended release or transdermal oxybutynin are other possibilities. Side effects include constipation, urinary retention, and confusion. Review annually, six months if over 75 years old.

Overflow incontinence:

• If secondary to bladder outlet obstruction, treat the cause, i.e., prostate hypertrophy, either benign or malignant.
• Intermittent self catheterisation, indwelling urethral or suprapubic catheterisation can be used.

Preventative measures include weight control, mainly for stress incontinence.