Back to Basics A&P

1. Back to BasicsA&P NZCA September 16, 2010

3. URETHRAL RESISTANCE • Smooth muscle • Striated muscle External urethral sphincter Pelvic floor muscles • Mucosal suppleness • Rotational effect of prolapse

7. INTRAVESICAL PRESSURE • Intrabdominal pressure Cough laugh sneeze, lifting etc Masses Sexual activity • Detrusor contraction pressure and compliance of bladder wall

8. 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.

9. Normal cystometry Flat, normal

10. Detrusor Overactivity during coughing

11. Detrusor overactivity during filling and standing

13. Nerve supply: Definitions • Nerve: Cell body, axons, dendrites • Neuro-effector junctions • Central Nervous System • Peripheral Nervous System • Afferent and efferent

14. REFLEXES Three components: • Sensory nerve • Connecting nerve(s) in the spinal cord • Motor nerve Reflexes can be inhibitory or excitatory

15. Neuro-muscular transmission • Striated muscle Acetylcholine • Smooth muscle  Acetylcholine Bladder  Noradrenaline Bladder neck Prostate urethra * ATP, etc

16. Divisions of the CNS • Somatic S2-4 Voluntary • Autonomic Nervous System Parasympathetic S2-4 Stimulation of bladder, gut, mediates erection Sympathetic T10-12 Contracts urethral/prostatic smooth muscle, semen secretion, [Combination of all 3 divisions for ejaculation]

18. 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

19. 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

20. Neuropathic bladder • Sensation Normal, reduced, absent hypersensitive, distension feeling • Detrusor Normal, overactive, underactive, areflexic • Urethra Normal, dys-synergic, paralysed

21. 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?

22. 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?

24. 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?

26. Clinical cases 3. Since a prolonged obstructed labour in Africa, a patient has been totally incontinent of urine. What could cause this?

27. 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?

29. Clinical cases • What does on open or incompetent bladder neck, mean? Continent or not? On what does it depend?

32. Stress Incontinence: predisposing factors • Pregnancy, delivery, parity • Obesity • Chronic straining/coughing • Paralysed pelvic floor (eg cauda equina) • Drugs: alpha-blockers for HT

33. Striated muscle of urethra To treat spasm: • Drugs Baclofen • Surgery Sphincterotomy (Stents) Denervation Cut nerves Botox Bladder instillations

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