Neurourology

Question 1

What composes the upper and lower urinary tracts? What are functions of lower tract?

Answer 1

Upper: kidney, ureter
Lower: bladder, urethra for storage and periodic expulsion

Question 2

What kind of reflex does micturition depend on?

Answer 2

Spinal-pontine-spinal reflex pathway, aka supraspinal reflex

Question 3

What brain areas are involved in voluntary control of the bladder? What areas receive sensory input?

Answer 3

Motor: medial PFC and cingulate gyrus
Sensory: PAG, VPL (thal), insular cortex

Question 4

What will a lesion to medial PFC cause?

Answer 4

Urinary incontinence

Question 5

Describe the conscious viscerosensation of bladder pathway.

Answer 5

Bladder -> a-delta thinly myelinated fiber to DRG -> interneuron in S2,3,4 -> PAG, VPL -> insular cortex

Question 6

What causes stress incontinence?

Answer 6

Pressure from coughing, laughing, sneezing, lifting; due to bladder support issues

Question 7

What is urge incontinence? What are causes?

Answer 7

Sudden onset of intense urge, overactive bladder; bladder irritation/tumors, diabetes, bening prostatic hypertrophy

Question 8

What is overflow incontinence? Causes?

Answer 8

Cannot empty bladder, leading to overflow; benign prostatic hypertrophy

Question 9

What is functional incontinence? Causes?

Answer 9

Physical or mental impairment; paralysis or dementia

Question 10

What is reflex incontinence? Causes?

Answer 10

Urine loss without sensation/warning; SCI

Question 11

Describe innervation of the bladder.

Answer 11

ANS PSNS and SNS in inferior hypogastric plexus, and somatomotor pudendal n to external sphincter

Question 12

Where is the pontine micturition center? What does it do? What neurotransmitter does it use?

Answer 12

Dorsal part of rostral pons; part of voiding reflex to empty bladder when distention detected; glutamate

Question 13

How do SCI affect bladder control?

Answer 13

Renal failure due to lack of voiding reflex, requires catheterization

Question 14

Where are beta adrenergic sympathetic receptors on the bladder, and what do they do?

Answer 14

Detrusor muscle, for relaxation and storage of urine

Question 15

Where are alpha adrenergic sympathetic receptors on the bladder, and what do they do?

Answer 15

Internal urethral sphincter, to contract for continence

Question 16

What class of medicine can help urinary incontinence?

Answer 16

Cholinergic blocking drugs, although contraindicated in geriatrics for worsening cognitive impairment

Question 17

What are the three targets of sympathetics reflexes to maintain continence?

Answer 17

Inhibit ganglionic PSNS in bladder, inhibit detrusor (beta receptors), stimulate internal sphincter (alpha receptors)

Question 18

What is the external urethral sphincter reflex?

Answer 18

DRG detection of distention -> interneuron -> pudendal somatomotor to contract external urethral sphincter

Question 19

What is the guarding reflex?

Answer 19

After intense abd/perineal stimulation DRG -> interneuron -> pudendal to contract external urethral sphincter

Question 20

How does guarding reflex change after SCI?

Answer 20

Interneuron inhibits pudendal nerve instead of exciting, leading to relaxation of external urethral sphincter

Question 21

What is the pathway for voluntary inhibition of micturition?

Answer 21

DRG distention -> inter -> PAG/VPL -> insula, PFC, cingulate -> mPFC -> inhibit PMC & activate pudendal n -> external sphincter

Question 22

What happens when bladder long tracts aren’t myelinated? In whom is this common?

Answer 22

Loss of bladder control; infants and MS

Question 23

What happens when there are lesions to medial prefrontal urinary area? What may cause this?

Answer 23

Frontal-type incontinence; falx cerebri meningioma, anterior cerebral a infarct, frontal medial TBI, etc.

Question 24

What is lesioned to cause areflexic/flaccid bladder?

Answer 24

Loss of detrusor contraction (lesion PSNS S2,3,4, pelvic splanchnic n, or DRG viscerosensory in diabetic neuropathy) and loss of external sphincter control if cord lesion S2,3,4 (pudendal)

Question 25

What are consequences of areflexic bladder?

Answer 25

Urinary retention and overflow, atrophy of detrusor

Question 26

What causes hyperreflexic bladder?

Answer 26

SCI above sacral cord or brain lesion (mPFC, post limb internal capsule). Flaccid, then over time C-fiber replaces A-delta fiber, projecting to different interneurons, to sacral PSNS pregang -> chronic firing of detrusor

Question 27

Which types of neurogenic bladder are considered LMN and UMN bladder lesions?

Answer 27

LMN: areflexic/flaccid
UMN: hyperreflexic/spastic

Question 28

What is detrusor-external sphincter dyssynergia?

Answer 28

After spastic bladder forms, ext sphincter contracts and does not relax; hypertrophy of detrusor and urge incontinence

Question 29

What are the consequences of acute SCI/neurogenic shock?

Answer 29

Hypotension, bradycardia, priapism, loss of bulbo-anal reflex, temporary reflex loss below lesion (until shock over)

Question 30

What is autonomic dysreflexia?

Answer 30

After SCI above T6, SNS below lesion not regulated. Simple stimuli like full bladder cause vasoconstriction sub-diaphragmatic aa

Question 31

What are the 3 classic signs of autonomic dysreflexia?

Answer 31

Sudden onset of hypertension, sweating above level of lesion, cutaneous vasodilation above level of lesion

Question 32

Why is a headache in an SCI patient potentially lethal?

Answer 32

Sign of potentially fatal hypertension stroke due to norepi from postgang SNS

Question 33

Why does SCI cause cutaneous sweating above the lesion?

Answer 33

Heat stress to hypthal via ALQ -> T-L pregang SNS above lesion -> postgang with ACh -> sweating above level of lesion b/c no input below lesion