Normal micturation and voiding dysfxn

Question 1

Impacts of urinary incontinence

Answer 1

• Physical limitations
• Psychological
• Social
• Domestic
• Ocupational
• Sexual

Question 2

Control of voiding 1

Answer 2

• Continence is learned: cognitive control over a reflex arc
• Bladder is SM, internal sphincter is SM, external sphincter is striated and SM
• Somatic nerves (pudendal nerves) relay to CNS bladder fullness
• These nerves will also provide somatic control of the external sphincter
• Before learned continence, this afferent signal causes a reflex efferent signal thru the pelvic nerves (PsNS) to relax the sphincter and initiate detrusor contraction and voiding

Question 3

Control of voiding 2

Answer 3

• This process is what causes normal voiding even after continence is learned
• What controls continence is an SNS efferent stimulation (via hypogastric nerves) that causes constriction of the bladder neck and urethral sphincters to prevent voiding, while also inhibiting the PsNS reflex
• When there is conscious desire to urinate, the SNS reflex is shut allowing the PsNS and somatic stimulation to permit voiding

Question 4

Neuroanatomy of voiding

Answer 4

• Brain: cortex inhibits voiding and pons facilitates voiding
• Spinal cord: spinal tract and nuclei
• Local: pudendal nerve somatic sensory (afferent limb of reflex arc) and pelvic nerve PsNS (efferent limb of reflex arc)
• Sympathetics: increase sphincter tone, but little clinical significance
• PsNS (pelvic nerve): required for detrusor contraction
• Somatic sensory (pudendal nerve): sensation of bladder fullness
• Cerebral cortex: required for detrusor-sphincter coordination, inhibits reflex arc

Question 5

Normal bladder function

Answer 5

• Bladder fills under low pressure (high sphincter pressure), and urge to void increases as bladder is stretched
• Continence allows us to inhibit the reflex arc (via suppression of PsNS efferent limb) by cortex
• Pons will disinhibit the PsNS reflex to allow for voiding when acceptable
• Voiding: relaxation of urethral sphincter followed by bladder contraction until empty

Question 6

Abnormal bladder function

Answer 6

• Filling: poor compliance, overactive bladder, poor sphincter activity, disruption in communication btwn bladder and brain (injury to cortex)
• Storage: overstretched detrusor (chronic obstruction, loss of sensation), injury to spinal cord or pons
• Emptying: non-relaxation of outlet, obstructed outlet, poor bladder contraction (areflexia: motor, sensory, neurogenic origins)

Question 7

Abnormal bladder function etiologies 1

Answer 7

• Idiopathic (non-neurogenic): must rule out other issues like BPH, UTI, bladder tumor, stones
• If these are ruled out idiopathic is over active bladder (OAB)
• Neurogenic: UMN or LMN
• Can be from MS, spinal cord injury, transverse myelitis, CVS, parkinson’s
• UMN: can affect bladder (detrusor overactivity) or sphincter (dyssynergy)

Question 8

Abnormal bladder function etiologies 2

Answer 8

• LMN: can affect bladder (areflexic) or sphincter (decreased response)
• Lesions at or above brainstem: intact sensation and sphincter, w/ detrusor overactivity
• Lesions at the spinal cord: detrusor overactivity w/ dyssynergic sphincter, sensation variable
• Lesions distal to spinal cord: bladder areflexic, sensation variable, sphincter variable

Question 9

Voiding dysfxn

Answer 9

• Failure to empty: b/c of bladder or outlet
• Failure to store: b/c of bladder or outlet
• Incontinence is failure to store
• B/c of urethra: stress urinary incontinence
• B/c of bladder: urge incontinence (OAB)

Question 10

Categorization of incontinence

Answer 10

• Stress urinary incontinence: due to poor outlet resistance (sphincter problem)
• Sx: cough, sneeze, exercise all cause voiding
• Dry at night or when sedentary w/ little frequency or urgency
• Often small volume
• Urge incontinence: due to OAB, but may be mixed (w/ SUI)
• OAB usually idiopathic/neurlogic
• Sx: urgency prior to leakage or leakage w/o awareness
• Wet at night w/ frequency, urgency, no relationship to activity
• Often large volume, frequent urge to void, “can’t make it to bathroom”

Question 11

Overflow

Answer 11

• Due to failure to empty
• Sx: straining to void, poor sensation, frequency
• Can be neurologic, BPH, prostate CA, stricture, diabetes

Question 12

Rx for overactive bladder

Answer 12

• Pads, behavior Rx, meds, neuromodulation, surgery
• Behavioral Rx: diet, timed voiding, pelvic exercises, reinforcement, delayed voiding
• Meds (anticholinergics): increase volume to bladder contraction, time btwn voids, does not increase warning time, decreases magnitude of bladder contraction