Back to BasicsA&P

NZCA

September 16, 2010

URETHRAL RESISTANCE

Smooth muscle Striated muscle

External urethral sphincter

Pelvic floor muscles Mucosal suppleness Rotational effect of prolapse

INTRAVESICAL PRESSURE

Intrabdominal pressure

Cough laugh sneeze, lifting etc

Masses

Sexual activity Detrusor contraction pressure and

compliance of bladder wall

DEFINITIONS

Overactive Bladder (OAB) symptomsIncreased frequency/ nocturiaUrgency +/- urgency incontinence

Detrusor Overactivity A urodynamic observation characterised by

involuntary detrusor contractions during the filling phase.

Normal cystometry

Flat, normal

Detrusor Overactivityduring coughing

Detrusor overactivity during filling and standing

Nerve supply: Definitions

Nerve: Cell body, axons, dendrites Neuro-effector junctions Central Nervous System Peripheral Nervous System Afferent and efferent

REFLEXES

Three components: Sensory nerve Connecting nerve(s) in the spinal cord Motor nerve

Reflexes can be inhibitory or excitatory

Neuro-muscular transmission

Striated muscle

Acetylcholine Smooth muscle

Acetylcholine Bladder

Noradrenaline Bladder neck

Prostate

urethra

* ATP, etc

Divisions of the CNS

Somatic S2-4 Voluntary Autonomic Nervous System

Parasympathetic S2-4Stimulation of bladder, gut, mediates erection

Sympathetic T10-12Contracts urethral/prostatic smooth

muscle, semen secretion, [Combination of all 3 divisions for ejaculation]

Voiding: How do you do it?

Relax Pelvic floor Afferents signal back to pons and higher

centres:

to stimulate the detrusor contraction

Relax the urethra until bladder empty

Continent between voids: How?

Bladder: low pressure reservoir Urethra:

Contraction increases as the bladder fills

Rises in abdominal pressure transmitted to the urethra, plus active contraction

Neuropathic bladder

Sensation Normal, reduced, absent hypersensitive, distension feeling

Detrusor Normal, overactive, underactive, areflexic

Urethra Normal, dys-synergic, paralysed

Case 1. Mid-thoracic (T6) spinal injury

Will this man have floppy legs, or legs that show spastic activity?

What activity would you expect in his bladder?

Could both erection and ejaculation be preserved?

Case 2. A man with a cauda equina injury at L3

What tone would you expect in his legs, and bladder?

Could he have erections? Could he ejaculate?

If ‘he’ were a ‘she’

How could she empty her bladder?

Would she be continent?

Clinical cases

1. Prostatectomy involves resecting the bladder neck and its sphincter function.

Are men incontinent post-TURP? Why?

2. A man with a ruptured urethra from a # pelvis has destroyed his external urethral sphincter.

Will he be continent? Why?

Clinical cases

3. Since a prolonged obstructed labour in Africa, a patient has been totally incontinent of urine.

What could cause this?

Clinical cases

4. After vaginal surgery, a woman develops a urethro-vaginal fistula.

Will she be continent?

5. A child is born with an ectopic ureter opening into the vagina near the cervix.

Will she be continent? Why?

Clinical cases

6. What does on open or incompetent bladder neck, mean?

Continent or not?

On what does it depend?

Stress Incontinence: predisposing factors

Pregnancy, delivery, parity Obesity Chronic straining/coughing Paralysed pelvic floor (eg cauda equina) Drugs: alpha-blockers for HT

Striated muscle of urethra

To treat spasm:Drugs Baclofen Surgery Sphincterotomy

(Stents)Denervation

Cut nervesBotoxBladder instillations

Mucosal suppleness

Factors influencing: Submucosal vascularity Epithelial thickness Absence of scarring eg DXT, surgery