Urinary incontinence is the involuntary leakage of urine. It is a common and distressing problem, which can have a large impact on quality of life. There are several triggers, types and causes with most cases occurring in elderly, postmenopausal, parous women.

Classification and Pathophysiology

There are two main types of urinary incontinence; stress incontinence and urge incontinence – with mixed incontinence describing patients with features of both types (most common).

Stress Incontinence

Stress incontinence is defined as the involuntary leakage of urine during increased intra-abdominal pressure (in the absence of a detrusor contraction like during coughing, sneezing, sitting)

It is typically seen after childbirth, which is the most common causative factor, having resulted in denervation of the pelvic floor. Other risk factors include oestrogen deficient states, pelvic surgery and irradiation.

Urge Incontinence

Urge incontinence (also known as overactive bladder syndrome) is the presence of urgency, usually with frequency and nocturia. Patient passes ( leaks ) large quantities of urine on the way to washroom.

Urodynamic testing typically shows over-activity of the detrusor muscle. This is the type of incontinence seen in neurological conditions like multiple sclerosis or spina bifida – however most cases are idiopathic and some caused by pelvic/incontinence surgery itself or urinary infections.

Other Causes

There are other causes that should be considered in the assessment of any patient with urinary incontinence:

1. Overflow incontinence – leakage of urine from an overfull urinary bladder, often in the absence of any urge to urinate.
2. Bladder fistulae – opening between the bladder and another organ (e.g. the vagina or rectum).
3. Urethral diverticulum – out-pocketing of the urethra into the anterior vaginal wall.
4. Congenital anomalies – e.g. ectopic ureter.
5. Functional incontinence – physical or mental barriers that prevent the patient reaching the toilet (e.g immobility, dementia).
6. Temporary incontinence – due to reversible factors such as constipation and urinary tract infection.

Clinical Features

Stress Incontinence

Stress urinary incontinence is the involuntary leakage of urine on exertion. Typically, this occurs when intra-abdominal pressures rise and this is communicated through to the bladder, resulting in leakage on coughing, sneezing or exercise. As such, this is the symptom with which women present. The leakage is often a small volume coinciding with physical stress

Urge Incontinence

Urge incontinence describes the sensation of urgently needing to pass urine, resulting in involuntary leakage. Patients will often complain of urgency (“If they have to go they have to go’’), frequency and nocturia. There are often trigger factors such as hearing running water, cold weather, etc. There are typically large volumes of leakage compared to stress incontinence.

Patients will often complain of urgency (“If they have to go they have to go’’), frequency and nocturia. There are often trigger factors such as hearing running water, cold weather, etc. There are typically large volumes of leakage compared to stress incontinence.

Investigations

In a patient presenting with urinary incontinence, we exclude infection of the urinary tract.

Summary

1. Urinary incontinence can be subdivided into stress incontinence, mixed and urge incontinence.
2. It is important to remember that these are debilitating conditions for patients and a major disruption to their lives
3. Exclusion of urinary tract infection must be done in any patient presenting with incontinence.
4. Conservative management is indicated in almost all cases
5. Medical therapy is indicated in both types of incontinence but surgical intervention is only to be considered as a last resort in those patients with urge incontinence.