Urinary Function (PKenny)

Question 1

where does neurological control of the bladder originate?

Answer 1

Lumbosacral spine
- L1-L4, S1-S3
> hypogastric n. (L1-L4)
> pelvic n. (S1 - S3) 
> pudendal n. (S1-S3)

Question 2

What is the bladder and urethra made up of/controlled by?

Answer 2

> Bladder
- detrusor m. (smooth m)
> urethra 
- internal urethral sphincter (smooth m)
- external urethral sphincter (skeletal m) controlled by pudendal n.

Question 3

Where is the micturition centre located?

Answer 3

Pons

- receives input from cerebrum too

Question 4

What NTs control the micturition reflex?

Answer 4

1. storage phase (sympathetic)
   - bladder relaxed (B adrenergic Rs of hypogastric)
   - urethra contracted (A adrenergic Rs of hypogastric and nicotinic cholinergic Rs of pudendal n)
   + inhibition of parasympathetic
2. voiding phase (parasympathetic)
   - bladder contraction (Ach muscarinic cholinergic Rs of pelvic n.)
   - relaxation of the urethra d/t lack of symp tone
   + inhibition of sympathetic fibres

Question 5

What is UMN bladder?

Answer 5

Lesion anywhere from pons - L7

• UMN inhibition lost -> ^ tone
• turgid easily palpable bladder
• ^ urinary sphincter tone
• may be some overflow leakage

Question 6

What is LMN bladder?

Answer 6

Lesion sacral SC or sacral nn. (seen with cauda equina syndrome)

• v tone
• flaccid, hard to palpate bladder
• v urinary sphincter tone
• passive leakage of urine

Question 7

Problems associated with neurogenic bladder dysfunction?

Answer 7

• ncontinence
• urine scald
• urine stasis -> UTI -> pyelonephritis
• detrusor atony d/t over stretching of sm. m. tight junctions
• pain

Question 8

How can voluntary micturition be distinguished from overflow?

Answer 8

Palpate bladder

Question 9

Management of neurogenci bladder dysfunction

Answer 9

> physical management usually necesary 
- manual expression 
- urethral catheterisation (indwelling or permenetn)
- cystotomy tube (long term) 
> pharmacological manipulation 
- to assist manual

Question 10

Give 5 drugs used to manipulate bladder function and their mechanisms of action

Answer 10

> diazepam
- centrally acting muscle relaxant
- v external urethral tone
- give 1 hr pre expressing bladder
Bethanechol (?? off market now?)
- muscarinic cholinergic agonist (parasympathomimetic)
- facilitates detrusor muscle contractility
- do not give if ^ urethral tone will -> rupture
Phenoxybenzamine and Prazosin
- a-adrenergic antagonist
- v internal urethral sphincter tone
- can use in conjunction with Bethanechol
Phenylpropanolamine (PPA)
- mixed a+b adrenergic agonist
- ^ internal urethral sphincter tone
- tx of incontinence rather than urine retention

Question 11

What does ^ protein in a CSF tap indicate?

Answer 11

Non specific sign

Question 12

How can caudal sacral lesions be differentiated from nerve roots?

Answer 12

Cant really - v difficult

- could be L7-cauda equina or spinal n roots