021115 voiding dysfxn

Question 1

CNS’ role in micturition

Answer 1

voluntary control

inhibition of reflex detrusor contraction

Question 2

PNS’ role in micturition

Answer 2

autonomic-involuntary

parasym: facilitates micturition
sympath: facilitates urine storage

Question 3

how does parasym facilitate micturtion

Answer 3

direct motor activation of detrusor contraction (Ach, muscarinic receptor)

indirect facilitation of detrusor contraction via stretch receptors

Question 4

how does sympath facilitate urine storage

Answer 4

inhibition of detrusor (direct-beta3 adrenergic receptor. indirect via inhibition of parasym stimulation)

contraction of internal sphincter/bladder neck via alpha adrenergic receptors

Question 5

how does somatic control of micturition work?

Answer 5

innervates external urethral sphincter

Question 6

micturition reflex

Answer 6

autonomic reflex btwn bladder and sp cord promoting bladder emptying

bladder fills w urine causing stretch of wall. stretch receptors activated-send signals to sp cord that promote detrusor contraction

Question 7

micturition reflex is modulated by

Answer 7

CNS
CNS sends inhibitory signals to shut down micturition reflex in cognitively intact people

micturition reflex can also be abolished by external sphincter contrac

Question 8

what coordinates voiding?

Answer 8

pontine micturition center:

• detrusor contrac (parasym innervation)
• internal sphincter relaxation (sympath innervation)
• external sphincter relaxation

Question 9

what can cause failure to store urine?

Answer 9

overactive detrusor

underactive detrusor w/ chronic urinary retention and bladder overdistension–overflow incontinence

stress incontinence (if you cough, etc)–causing urethral sphincter to be weak

Question 10

what causes a failure to empty urine?

Answer 10

weak detrusor (neurogenic, myogenic, psychogenic, med)

urethral obstruction:

• anatomic (prostatic enlargement, urethral stricture, prior incontinence surgery)
• functional (hyperactive sphincter)-neurogenic which is detursor-sphincter dyssnergia due to MS or sp injury etc. or non-neurogenic which is dysfunctional voiding

Question 11

hyperactive destrusor

Answer 11

bladder decides to empty independent of brain’s control

Question 12

what causes an overactive bladder?

Answer 12

inflam/infec
bladder irritants (food, alcohol)
neurologic conditions (sp cord injury, stroke, MS)
metabolic conditions (diabetes)
urethral obstruction (causes secondary active bladder)

also associated w: lack of estrogen, obesity, pelvic organ prolapse, pelvic floor dysfxn

Question 13

tx for overactive bladder

Answer 13

behavioral therapies:

• fluid management
• pelvic floor exercises (inhibit detrusor contrac by contracting urinary sphincter/pelvic floor)

meds:

• anticholinergics
• beta 3 adrenergic agonist (activates beta 3 recptor in detrusor to relax detrusor)

surgery

Question 14

risk factors for stress urinary incontinence

Answer 14

vaginal/pelvic trauma (pregnancy, etc)
lack of estrogen
neurologic
radiation therapy-scarring
obesity

Question 15

tx for stress incontinence

Answer 15

behavioral therapies (weight loss, pelvic floor exercises)

medication (technically no approved drug for it)

surgery

Question 16

what kinds of meds can cause detrusor weakness

Answer 16

anticholinergics (psychiatric, anesthetic)
alpha-agonist (cold meds)
narcotics

Question 17

symptoms of urinary retention

Answer 17

voiding difficulty
urinary frequency (from lack of bladder emptying)
lower abd pain (acute)
overflow urinary incontinence (chronic)
distended bladder
hydronephrosis/renal failure
leaking

Question 18

management of retention

Answer 18

• catheter drainage of bladder
• treat UTI (heightened sympath state can tighten sphincter)
• stop aggravating meds
• relieve any obstruction (use alpha blocker to reduce internal sphincter tone, surgery on prostate)
• neuromodulation

Question 19

if you have surgery for brain tumor, how can does adverseley affect micturition

Answer 19

can cause infantile state in which CNS is not controlling the reflex to urinate