Back to Basics A&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) symptoms Increased frequency/ nocturia Urgency +/- urgency incontinence Detrusor Overactivity A urodynamic observation characterised by involuntary detrusor contractions during the filling phase.

Normal cystometry Flat, normal

Detrusor Overactivity during 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  AcetylcholineBladder  NoradrenalineBladder neck Prostate urethra * ATP, etc

Divisions of the CNS SomaticS2-4 Voluntary Autonomic Nervous System Parasympathetic S2-4 Stimulation of bladder, gut, mediates erection SympatheticT10-12 Contracts 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 SensationNormal, reduced, absent hypersensitive, distension feeling DetrusorNormal, overactive, underactive, areflexic UrethraNormal, 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 nerves Botox Bladder instillations

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