Urinary Incontinence

Continence is acquired by children as a result of maturation of the nervous system.

A constant flow of nervous impulses is needed to keep the sphincter closed.

For most people, most of the time continence is automatic, we don't need to think about it all the time.

Need occurs at 200 mls, after this volume need increases.

Urethral pressure - urine in

maintained by urethral sphincters and pelvic floor

Bladder pressure - urine out

maintained by contraction of bladder muscle and rise in intra - abdominal pressure, eg. laughing, pregnancy etc.

Normally bladder pressure will exceed urethral pressure when we decide to pass urine

Causes of incontinence

Urological and Gynaecological causes

Pelvic muscle weakness - stress incontinence

Infection

Cancer

Fistula

Prostate gland enlargement

Medical causes

Poor physical mobility - failure to get there

Drugs

Alcohol excess

Diabetes mellitus

Confusion

Depression

Neurological causes

Any CNS pathology or trauma

Peripheral nerve disorder

Environmental factors

Inappropriate furniture

Cot - sides

Distance from toilet

Poor lighting

Getting lost

Poor clothing

Sound of running water

The four main types of incontinence

1. Urgency and Urge incontinence

Causes of urgency;

* unstable bladder contractions

* hypersensivity of stretch receptors

* diuretics

* cystitis/infection

* ageing, (hormonal factors)

* anxiety

2. Stress incontinence

Weakness of the pelvic floor and urethral sphincter

Often noticed for the first time after childbirth

Also occurs around the menopause

"Giggle incontinence" may occur in young girls

Men may also suffer.

3. Retention and overflow

Involuntary loss of urine with over - distension of the bladder.

Failure of bladder ability to contract or urethral obstruction.

Residual urine left after micturition.

Dribbling becomes an almost constant feature

Examination reveals bladder enlargement.

Causes

* loss of bladder tone

* Prostate enlargement

* Post traumatic fibrosis

Reflex incontinence

Loss of higher spinal cord control results in voiding via the sacral reflex arc as in babies.

Large volumes are passed with no previous sensation of need.

Neurological damage can also cause over-active bladder activity and involuntary urethral relaxation.

Micturition

Autonomic and voluntary nervous systems

Detrusor contraction is parasympathetic

Internal sphincter closed by sympathetic activity

During micturition sphincter relaxes due to less sympathetic activity

External sphincter is voluntary

Nerve impulses from the cerebral cortex increases parasympathetic and reduce sympathetic activity causing relaxation of the internal sphincter and contraction of the bladder muscle

The pudendal nerve relaxes the external sphincter under voluntary control

Intra-abdominal pressure is also increased