Conditions such as diabetes, stroke, spinal injury and multiple sclerosis involve the nervous system and so will have some impairment of bladder function.

Neurogenic incontinence

Neurogenic incontinence occurs when there is damage to the nerves involved in bringing about bladder relaxation or contraction, and the co-ordination of the bladder-neck mechanism.

The bladder, like all other vital organs, is under the control of the nervous system.  When things go wrong, the normal function of that organ becomes impaired.  The bladder muscle is important in both the filling and voiding phases of bladder function.

If the filling phase has some nervous impairment then the bladder muscle will not relax to accommodate a good volume of urine.  It often becomes irritable or unstable, meaning the bladder muscle is over-excited, the symptoms experienced by the person being urgency and urge incontinence.

If the voiding phase is impaired, the bladder muscle will be unable to contract (squeeze down) to empty.  This condition leads to residual urine, overflow leaking, and dribbling incontinence.

If the co-ordination between the bladder contracting and the bladder-neck opening is affected (dyssynergia), the experience will be the urgent need to pass urine but an inability to initiate the void (start passing water).  Then, without conscious control, the bladder neck opens leading to a loss of urine without warning.

Bladder problems can arise following back injury or slipped disc.  If the injury has occurred around the level of S234 (sacral bone 2,3, and 4) where the nerves enter, the bladder may be damaged at the time of injury but symptoms may not become apparent until many years later.  Signs of damage may be repeated urinary-tract infections, increasing poor stream, and dribble incontinence.

Investigating neurogenic incontinence

The neurogenic bladder will always need full urological investigation.  Extensive tests will be carried out in hospital by a consultant urologist or neurologist to determine the cause.  It is important to be screened to eliminate a high-pressure bladder that could lead to subsequent kidney damage.

Any degenerative disease of the nervous system may result in problems of bladder control and should be always carefully investigated.

Reflex incontinence

All babies have reflex incontinence.  The bladder fills and empties without instruction from the higher centre, the brain.  The baby's bladder continues to empty in this way until the development of the long nerve pathways to the brain.  Bladder control is developed between the age of 18 months and 4 years.

Reflex incontinence may occur following spinal injury, when the brain is no longer able to receive messages from the bladder, so control is lost.  It is also more common in older people with senile dementia. 

20/05/2009