Incontinence

Urinary incontinence: causes

▶Incontinence has a major adverse impact on quality of life and has significant associated morbidity (it may be the last straw leading to institutionalization). Even longstanding cases may be reversible so always explore continence issues even if everyone else is complacent.

It is very common (around 30% of elderly at home, 50% in care homes) but is not a natural consequence of ageing. Most incontinence in older people is multifactorial, so think of all the possible contributing factors and address each in turn. They can be divided as follows:

Age-related changes

Diminished total bladder capacity but increased residual volume
Diminished bladder contractile function
Increased frequency of uninhibited bladder contractions
Reduced ability to postpone voiding
Excretion of fluid later in the day with less concentrated night-time urine
Atrophy of vagina and urethra in females
Loss of pelvic floor and urethral sphincter musculature
Hypertrophy of the prostate in males

Comorbidity

Diminished mobility—may have an urge to urinate then not be able to get to the toilet in time
Prescribed medications affect lower urinary tract, conscious state (eg sedatives) or ability to get promptly to the toilet (eg antihypertensives causing postural drop)
Increased constipation
Impaired cognition— a continent person needs to be able to recognize that they need to urinate, locate and reach a toilet, then undress in time to pass urine in the right place. Confusion can cause inappropriate micturition (initially failure to find an appropriate receptacle, then in later dementia they may be unaware altogether of urination). There may also be interference with UMN input into continence pathways

Reversible factors

UTI (see ‘Urinary tract infection’, p.621)
Delirium
Drugs eg diuretics cause polyuria, anticholinergics such as tricyclics cause retention, sedatives can reduce awareness or mobility
Constipation—may cause voiding difficulty and increased residual volumes in both sexes
Polyuria (eg poorly controlled diabetes, hypercalcaemia, oedema resorption at night can cause nocturnal polyuria, psychogenic polydipsia)
Urethral irritability (eg atrophic vaginitis, candida infection)
Prolapse (women)
Bladder stones and tumours

Irreversible (but treatable) factors

In males, prostatic hypertrophy or carcinoma causes outflow obstruction, an unstable bladder or ‘overflow’ incontinence
Overactive bladder syndrome (symptom diagnosis)/detrusor overactivity (urodynamic diagnosis)—spontaneous contractions of the bladder muscle causes urgency and frequency ± incontinence
In females, outlet incompetence (stress incontinence)—usually due to pelvic muscle and ligament laxity (which supports the urethra) following childbirth—any rise in intra-abdominal pressure causes small leaks eg with cough, hoisting
Mixed symptoms—suggesting the presence of both overactivity and stress incontinence
Fistula (connection between the bladder and vagina) can occur after pelvic malignancy and irradiation, causing constant wetness

Environmental factors

Being bed bound and reliant on assistance with toileting makes continence a challenge. Whilst nurses will endeavour to promptly attend to a request for toileting, there is an inevitable delay
In males with reduced mobility, a lack of manual dexterity and/or small penile size can make the use of bottles a challenge
In hospitals, the toilet may be further away than at home, or difficult to find. In addition, the acute illness may mean that mobilizing is difficult
At home, access to a toilet may become harder with reducing mobility (eg if there is only an upstairs toilet)

Urinary incontinence: assessment

Much is made in the literature of the different symptoms in different diagnostic groups.

Urgency symptoms Frequent (>8 times per day) and/or precipitant voiding— strong urge, and decreased time to reach the toilet. If incontinence occurs this is termed wet overactive bladder (OAB). Urge alone whilst maintaining continence is dry OAB and may be a precursor to the wet form. Nocturnal incontinence common. Urge symptoms are commonly due to detrusor muscle overactivity where the residual volume small, but can also occur in obstruction
Stress symptoms Small volume leaks during coughing, laughing, lifting, walking and other exercise. Often coexist with urge symptoms in women
Obstructive symptoms in men include decreased force of urinary stream, hesitancy, and intermittent flow

Older patients are often unable to give precise descriptions and the different symptom complexes can overlap. Even where a ‘pure’ symptom complex exists you may get the diagnosis wrong, eg prostatic outflow symptoms where incontinence is actually detrusor overactivity or symptoms of urgency as a presentation for retention with overflow. Additional factors such as reduced mobility, dexterity, and cognition also interact to produce the syndrome of incontinence.

A more pragmatic approach is often required.

Take a history—a bladder or voiding diary can help, especially if you are relying on carers for information. Ask questions such as:
- ‘Do you know when you need to go to pass urine?’
- ‘Do you get much time between getting the urge and when the urine comes?’
- ‘Do you sometimes leak urine when you cough or run?’
Examination—include vaginal, rectal, and neurological examination
Exclude a significant residual volume See Box 20.1
Investigations—urinalysis and midstream urine (MSU), general screening blood tests, cytology and cystoscopy if haematuria. Urodynamics can be helpful if patient’s incontinence cannot be explained or they are not responding to treatment and essential if surgical intervention is contemplated

Box 20.1 Residual volume

Normal young people have only a few mL of urine post-micturition but normal elderly can have up to 100mL.

Causes of raised residual volume include:

Prostatic hypertrophy, carcinoma
Urethral stricture
Bladder diverticulum
Large urinary cystocele and other pelvic organ prolapsed (females)
Hypocontractile detrusor
Neurological disease eg Multiple sclerosis, Parkinson’s disease, spinal cord disease, disc herniation
Bladder tumour
Drugs eg tricyclic antidepressants, anticholinergics

Acute retention is usually painful but can present atypically with delirium, renal failure etc.

Chronic bladder distention is usually painless, presenting with infection, abdominal distension/mass or incontinence (continuous dribbling due to overflow or urge incontinence due to detrusor instability).

Persistently elevated residual volume increases the risk of infection.

If pressure is elevated this can cause dilation of the urinary tract and eventually hydronephrosis and renal failure.

Residual volume can easily be estimated using a simple ultrasound bladder scan or a diagnostic (in/out) catheterization.

Bladder diaries

It is helpful to ask patients and/or carers to complete a bladder diary to aid assessment. This should include the timing and volume of all urine voided along with details of any symptoms and episodes of incontinence. An example is shown in Table 20.1.

Analysis of this will allow correct assessment of: