Urinary Function (PKenny) Flashcards
where does neurological control of the bladder originate?
Lumbosacral spine - L1-L4, S1-S3 > hypogastric n. (L1-L4) > pelvic n. (S1 - S3) > pudendal n. (S1-S3)
What is the bladder and urethra made up of/controlled by?
> Bladder - detrusor m. (smooth m) > urethra - internal urethral sphincter (smooth m) - external urethral sphincter (skeletal m) controlled by pudendal n.
Where is the micturition centre located?
Pons
- receives input from cerebrum too
What NTs control the micturition reflex?
- 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 - 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
What is UMN bladder?
Lesion anywhere from pons - L7
- UMN inhibition lost -> ^ tone
- turgid easily palpable bladder
- ^ urinary sphincter tone
- may be some overflow leakage
What is LMN bladder?
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
Problems associated with neurogenic bladder dysfunction?
- ncontinence
- urine scald
- urine stasis -> UTI -> pyelonephritis
- detrusor atony d/t over stretching of sm. m. tight junctions
- pain
How can voluntary micturition be distinguished from overflow?
Palpate bladder
Management of neurogenci bladder dysfunction
> physical management usually necesary - manual expression - urethral catheterisation (indwelling or permenetn) - cystotomy tube (long term) > pharmacological manipulation - to assist manual
Give 5 drugs used to manipulate bladder function and their mechanisms of action
> 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
What does ^ protein in a CSF tap indicate?
Non specific sign
How can caudal sacral lesions be differentiated from nerve roots?
Cant really - v difficult
- could be L7-cauda equina or spinal n roots