Micturition Flashcards
What are the two parts of the autonomic nervous system?
- Parasympathetic (rest and digest)
- Sympathetic (fight or flight)
Autonomic nervous system - voluntary or involuntary?
- Involuntary
How many neuron systems with ANS and bladder control?
- Two
- preganglionic and postganglionic
What does ANS innervate?
- Smooth muscles, hollow organs, sweat glands
Somatic control of the bladder - what type of muscle?
- Skeletal muscle
Is somatic control of the bladder voluntary or involuntary?
- VOLUNTARY
How many neurons involved in the somatic system?
- One!
- No preganglionic/postganglionic
Spinal cord region of the sympathetic nervous system
- Thoracolumbar
- T3-L3
Spinal cord region of the parasympathetic nervous system
- Craniosacral
- C1-T2
- L4-S3
Sympathetic preganglionic receptor and neurotransmitter type?
- Nicotinic cholinergic
- NT: ACh
Sympathetic postganglionic receptor (effector organ) and NT type
- Receptor: Adrenergic (alpha or beta)
- NT: Adrenaline derivative (epinephrine or norepinephrine)
Parasympathetic preganglionic receptor and neurotransmitter type?
- Receptor: Nicotinic cholinergic
- NT: Acetylcholine
Parasympathetic postganglionic receptor (effector organ) and neurotransmitter type?
- Muscarinic cholinergic
- NT: Acetylcholine
Somatic innervation receptor and NT type
- Nicotinic cholinergic
- NT: Acetylcholine
Where are somatic receptor organs?
- EVERYWHERE
Sympathetic receptor organs
- bladder, smooth muscle heart
Parasympathetic receptor organs
- Bladder, smooth muscle, heart
What are three components in the brain that influence bladder control?
- Forebrain
- Brainstem
- Cerebellar
Forebrain influence on bladder
- Learned behavior
- Voluntary control
Brainstem influence on bladder
- Coordinate spinal reflex arcs
- Mostly located in the pons
- Considered UMN for normal urination
Cerebellar influence on bladder
- Inhibitory over detrusor reflex
Detrusor muscle
- Smooth muscle surrounding the bladder
What does relaxed detrusor muscle do?
- fill the bladder
WHat does contracted detrusor muscle do?
- Empty the bladder
Bladder filling:
Which receptor type?
Which nerve?
Which spinal cord segments?
- Beta adrenergic
- Sympathetic via the hypogastric nerve (L1-L4)
Bladder emptying:
Which receptor type?
Which nerve?
Which spinal cord segments?
- Cholinergic (muscarinic)
- Parasympathetic (pelvic nerve) (S1-S3)
Where are sensory receptors for the bladder?
- Throughout the bladder wall
Which nerve responsible for stretch?
- Pelvic nerve (S1-S3)
Which nerve responsible for pain?
- Hypogastric nerve (L1-L4)»_space;» pelvic nerve (S1-S3)
What are the two sphincters of the bladder?
- Internal and external sphincter muscle (urethralis muscle)
Muscle type in internal sphincter?
- Smooth muscle of the proximal urethra
What does contracted internal sphincter do?
- Fill the bladder
What does relaxed internal sphincter do?
- Bladder emptying
Which receptor type for internal sphincter muscle?
Which nerve?
Which spinal cord segments?
- Alpha adrenergic
- Sympathetic via hypogastric nerve
- L1-L4
What muscle type is external sphincter?
- skeletal muscle of urethra
How does the external sphincter muscle contract or not?
- Same as internal sphincter muscle
Innervation to the external sphincter muscle?
- Somatic or pudendal nerve (S1-S3)
What are the four major arms of bladder retention and filling?
- Sensory input detecting stretch (detrusor muscle via pelvic nerve S1-S3)
- Hypogastric nerve L1-L4 control with detrusor relaxation under beta-adrenergic and internal urethral sphincter contraction under alpha-adrenergic
- Pudendal nerve (S1-S3) control under somatic for contraction of external urethral sphincter under the nicotinic cholinergic receptor
- Pelvic nerve iS1-S3 inhibition (inhibition of muscarinic cholinergic pathway)
What are the four major arms of bladder voiding/emptying?
- Sensory input (detrusor muscle via pelvic nerve S1-S3)
- Pelvic nerve (S1-S3) control - detrusor contraction under muscarinic cholinergic
- Hypogastric nerve (L1-L4) control inhibited to relax the external urethral sphincter
- Pudendal nerve S1-S3 control (somatic) is inhibited
Look at the helpful charts for urination
- Just do it - it’s really quite nice
Why do we care about the bladder with spinal cord injury?
- It can cause dysfunction of the bladder just like with the limbs downstream of hte lesion
- Requires proper maangement for the type of injury
- If ignored can lead to serious complications!
What should you NEVER EVER ASSUME?
That a dog can urinate!
Even if you see a puddle of urine next to a dog
Four steps if you find a neurologic patient with urine in its cage?
ULTIMATELY ASSESS THE BLADDER
- Allow patient to try and urinate - try to observe voiding or attempts to void (if they try to urinate carefully observe)
- Try to palpate the bladder (large and firm or soft, cannot feel)?
- Try to express the bladder? (easy or having to press forcefully)
- Ultrasound to assess size (large? Turgid? flaccid?)
What can result in an UMN bladder?
- Lesion from pons to L3
UMN bladder signs
- Cannot urinate or complete urination, pulsations
- Large, hard bladder, trying to push against an overactive internal urethral sphincter
- Difficult to express
Why does UMN bladder happen?
- Increased tone to pelvic limbs and bladder
- T3-L3 localization to the pelvic limbs?
- No motor? = NO BLADDER FUNCTION
Lesion for LMN bladder?
- Caudal to L4
Signs of LMN bladdre
- Cannot urinate or complete urination
- Large, either soft or non-palpable bladder
- Easy to express but difficult to empty, difficult to hold on
- Constantly leaking
Why does LMN bladder happen?
- Decreased tone to pelvic limbs, anus, and bladder
- Flaccid detrusors and sphincters
- L4-S3 localization to pelvic limbs?
- Can lose bladder function before motor function
Goals of bladder management
- Keep the bladder empty
- If you cannot achieve this manually without great distress, get some help from pharmacological manipulation!
UMN bladder ultimate pathophys
- Lack of inhibition due to localization of lesion
- Causes too much input from all the nerves controlling bladder filling
TOo much tone to internal urethral sphincter (hypogastric nerve L1-L4), detrusor muscle (pelvic nerve S1-S3), external urethral sphincter (pudendal S1-S3)
Fundamentals behind treating the UMN bladder?
- Use medication to decrease internal urethral sphincter tone
- Relax external urethral sphincter
- Release/relax body wall
What type of drug to counteract hypogastric nerve tone of the internal urethral sphincter with UMN bladder?
Alpha adrenergic antagonist
- Sympatholytic or parasympathomimetic
- Prazosin (more common; specific for alpha-1)
- Phenoxybenzamine is a non-specific antagonist
Side effects of alpha-antagonists?
- Hypotension
- Bradycardia
Drugs to relax external sphincter tone and body wall (pudendal nerve)?
- We need a muscle relaxant (Diazepam)
- Sedation (Acepromazine and dexmedetomidine)
Diazepam side effects
- Sedation
- Fatal hepatic necrosis in cats!!!
LMN underlying pathophysiology
- Destroys cell bodies
- Too little to no input to the pelvic and pudendal nerves
- Too decreased to no tone to detrusor muscle (pelvic nerve) and external urethral sphincter (pudendal nerve)
How to help with LMN decreased detrusor tone and external urethral sphincter?
- Use medication to increase detrusor tone
- Do not need to treat to increase internal or external urethral sphincters to limit leakage
- WOrks against trying to express
Drugs to increase detrusor muscle tone (pelvic nerve S1-S3)?
- Parasympathomimetic or sympatholytic
- Bethanechol (stimulates cholinergic receptors)
Side effects of bethanechol
- SLUD, GI hypermotility
- DO NOT USE ALONE
What should bethanechol be used with and why?
- Prazosin
- Need to relax the sphincters
Drugs to help increase internal urethral sphincter tone?
- Hypogastric nerve (L10L4)
- Alpha agonist (sympathomimetic)
- Phenylpropanolamine hydrochloride (mixed adrenergic agonist
- Estrogen (increases alpha receptors)
Side effects of phenylpropanolamine and estrogen?
- Hypertension and tachycardia
Look at the drugs table
Just do it!
Modes of expressing the bladder (and which is proper)
- Manual expression
- Intermittent catheterization
- Indwelling catheterization***
Things needed for intermittent catheterization
- Difficult to do in female patients
- Sterile
- Red rubber catheter
What can a puddle of urine mean?
- Overflow from too large of a bladder that cannot be emptied
- Large, distended, never fully emptied bladder
- Large, distended bladder that continually leaks
Reflex arc with UMN bladder and overflow
- Sensory input (detrusor muscle via pelvic nerve senses bladder stretch)
- Pelvic control (stimulates contraction of detrusor muscle AND relaxation of external urethral sphincter to allow the bladder to empty some volume)
What is the consequence of the reflex arc?
- DETRUSOR ATONY!
What is the risk with large, distended, never fully emptied bladder?
- UTI
- Ascending pyelonephritis
What is risk of large, distended bladder that continually leaks?
- Urine scalding
WORST consequences associated with an unmanaged bladder?
- UTI
- Detrusor atony
- Ruptured bladder
- Urine scald
