Incontinence

Question 1

causes of incontinence

Answer 1

Extrinsic to the urinary system
Environment, habit, physical fitness, etc.

Intrinsic to the urinary system
Problem with bladder or urinary outlet

Often a bit of both

Question 2

extrinsic factors impact on continence

Answer 2

Physical state and co-morbidities
Reduced mobility
Confusion (delirium or dementia)
Drinking too much or at the wrong time
Medications, e.g. diuretics
Constipation
Home circumstances
Social circumstances

Question 3

anatomy and physiology of continence

Answer 3

Continence depends on the effective function of the bladder and the integrity of the neural connections which bring it under voluntary control:

1 : Bladder and Urethra
2 : Local Innervation
3 : CNS Connections

Question 4

bladder and urethra function

Answer 4

Detrusor is smooth muscle
Internal urethral sphincter is smooth muscle
External urethral sphincter is striated muscle

Urine storage
Involves detrusor muscle relaxation with filling (<10CM pressure) to normal volume 400-600ML combined with sphincter contraction.

Voluntary voiding
Involves voluntary relaxation of external sphincter and involuntary relaxation of internal sphincter and contraction of bladder.

Question 5

local innervation of bladder and urethra

Answer 5

(T10-L2) : Sympathetic
ß - adrenoreceptor : causes detrusor to relax.

(T10-S2) : Sympathetic
a - adrenoreceptor : Causes contraction of neck of bladder, and internal urethral sphincter.

(S2-S4) : Parasympathetic
Increases strength and frequency of contractions

(S2-S4) : Somatic
Contraction of pelvic floor muscle (urogenital diaphragm) and external urethral sphincter.

Question 6

CNS connections for continence

Answer 6

Centres within the CNS inhibit parasympathetic tone, and promote bladder relaxation and hence storage of urine.

Sphincter closure is mediated by reflex increase in a-adrenergic and somatic activity.

Question 7

pontine micturation centre

Answer 7

The pontine micturition centre normally exerts a “storage program” of neural connections until a voluntary switch to a voiding program occurs.

Other areas involved include:
Frontal cortex
Caudal part of spinal cord

Question 8

intrinsic factors causing incontinence

Answer 8

Bladder
Outlet

Too weak - stress incontinence
Too strong - overflow continence
bladder muscle too strong - urge incontinence