Micturation (Cooke) Flashcards
1
Q
Detrusor muscle
A
- makes up the bladder
- has tight junctions
2
Q
Urethra
A
- ‘internal sphincter’
- has many components
- external sphincter
- striated muscle
- voluntary control of urination
3
Q
Bladder position
A
- normal position is important
- abdominal pressure presses on neck of bladder as well
4
Q
Uretovesicular junction
A
- ureters need to be located behind the sphincters for an animal to be continant
5
Q
Receptors in the wall of the bladder
A
- Beta receptors
- stimulation of these receptors cause relaxation of detrusor muscle
6
Q
Receptors in the internal urethral sphincter
A
- alpha receptors
- stimulation causes contraction/inc tone in smooth muscle of urethral sphincter
7
Q
Hypogastric nerve
A
- Comes from Lumbar cord segments 1-4 or 5 I think
- Sympathetic nervous system
- Excites B and alpha receptors on bladder and internal urethral sphincter
- sensory functions
- inflammation
- stretch
8
Q
Pelvic nerve
A
- part of the parasympathetic nervous system
- primary nuerotransmitter is acetylcholine
- Comes from Sacral Cord segements 1-3
- synapses on cholinergic receptors in detrusor muscle
- stimulation creates contraction of detrusor muscle
- sensory fibers
- sense normal stretch of filling bladder
9
Q
Pudendal nerve
A
- Comes from sacral segments
- Primarily somatic and motor fibers to external sphincter
- some sensory fibers
- urethra and neck of bladder
- responsible for voluntary control of bladder
10
Q
Phases of normal micturition
A
- Storage phase
- sympathetic dominance => hypogastric N.
- plus pudendal nerve => voluntary control
- Voiding phase (sensory)
- distention => pelvic nerve
- pain and overdistension => hypogastric nerve - cerebral cortex
- pons => to spinal cord => to pelvic n.
- Voiding phase (motor)
- coordinated response of
- bladder contraction
- urethral relaxation
- coordinated response of
11
Q
Following the schematic (normal micturition)
A
- Pelvic n. can sense distention
- Hypogastric n. can sense pain or over distension - carried up to brain
- Brain sends stimulus to hypogastric, pelvic, pudendal nerve
- inhibition of the hypogastric nerve - inhibition of tone in internal sphincter (alpha receptors)
- inhibition of pudendal n. for relaxation of external sphincter
- stimulation of pelvic nerve, release of achetylcholine and contraction of bladder
12
Q
disorders of micturition
Storage disorders
A
- components of normal storage
- ureteral position
- detrusor relaxation
- adequate urethral closure/tone
13
Q
Characteristics of storage disorders
A
- Voluntary urination is normal
- no stranguria, pollakiuria
- involuntary leakage
- normal residual volume
- post urination, blatter should be small
14
Q
disorders of micturition
voiding disorders
A
- components of normal voiding
- detrusor contraction
- urethral relaxation
- physical obstruction
15
Q
Characteristics of voiding disorders
A
- voluntary urination abdormal
- stranguria
- pollakiuria
- diminished urine stream
- usually postures
- Increased residual volume
16
Q
Clinical approach
A
- consider age
- young: congenital or housebreaking issues
- adult: acquired
17
Q
Questions to ask on a history
A
- When did it start?
- When does it occur?
- Urine stream?
- Awareness?
- Frequency?
- Volume?
- Straining, blood?
- Other problems?
18
Q
Physical exam elements
A
- Bladder size / tone
- before / after urination
- Perineal / preputial wetness / staining
- Rectal exam
- +/- vaginal exam
- especially if patient will be sedated for other purposes
- Neurological exam
- check anal tone
- check perineal reflex - retraction if you touch around anus
19
Q
Features of storage disorders
A
- Involuntary leakage / urination
- continuation
- intermittent
- Actual urination is normal
- bladder empties
- Stranguria uncommon
- may come about if problem has predisposed animal to urinary tract infections
20
Q
Features of voiding disorders
A
- Posturing to urinate
- Decreased urine passage
- Large residual volume
- Stranguria, pollakiuria
- +/- hematuria
21
Q
Clinical case: Problems - what are DDXs for young adult M-C cat
Stranguria
Pollakiuria
Pigmenturia
Large bladder
Bladder pain
Lethargy
A
- Urethral obstruction
- urethrolith
- matrix plug
- Functional obstruction
- urethrospasm
- +/- cystitis
- inflammatory
- infectious
22
Q
Storage disorders
A
- Urethral incompetance
- hormone resonsive
- congenital
- lower motor neuron disease
- Detrusor relaxation
- usually secondary
- Ectopic ureter
23
Q
Urethral sphincter mechanism incompetence
(USMI)
A
- Most common
- young-middle aged, spayed female dogs
- large breed > small breed
- Clinical features
- incontinence - usually at rest
- months to years post-spay
- +/- recurrent urinary tract infections
- Cause?
- effects of dec estrogen
- alpha-adrenergic receptor numbers?
- inc collagen/ dec muscle?
- effects of dec estrogen
- Diagnosis
- urethral pressure profilometry
- presumptive
-
TX
- increase urethral sphincter tone
- Phenylpropanolamine (PPA) - alpha agonist
- Estrogen (DES) - maybe upregulate number of alpha receptors
- other diagnostics
- other options -
- urethral occluder
- bulking agent injections
- increase urethral sphincter tone
24
Q
Pelvic bladder
A
- Clinical features (zebra diagnosis)
- similar to USMI
- maybe void spastically
- Diagnosis
- clinical signs + rads
- R/O other causes
- TX
- similar to USMI
- +/- sx to tack the bladder somewhere…lol
25
Detrusor spasticity
* Clinical features
* sudden voiding w/ small bladder
* usually secondary to inflammation
* infections
* cystoliths
* neoplasia
* idiopathic
* DX
* look for inciting inflammation / infection
* presumtive
* +/- cytometrography (rarely done)
* TX
* **underlying cause**
* enhance relaxation
26
Ectopic ureters
* Unilateral vs bilateral
* female \> male
* clinical features from birth
* females: often constant dribbling
* males: may dribble intermittently
* DX
* **cystoscopy**
* contrast radiography (DOUBLE)
* maybe abdominal U/S first
* +/- urodynamic testing (rarely done)
* TX
* laser ablation (intramural)
* surgery (extramural, no laser available)
* outcome
* 25-50% residual incontinence
* manage like USMI
27
2 yo, F-s, labrador reriever
leaking urine at night
no other accidents in the house
no stranguria or pollakiuria
previously well house-broken
**what is your top differential? TX?**
* USMI
* used to be housebroken so probs not ectopic ureter
* alpha adrenergic agonist
* stimulate the alpha receptors
\*ACh-receptor agonist would probably also stimulate bladder contraction, we don't want this
28
Voiding disorders
* Detrusor contraction
* atony
* lower motor neuron dz
* Urethral relaxation (functional obstruction)
* upper motor neuron disease
* urethrospasm
* physical obstruction
29
Detrusor atony
* acquired most common
* post obstruction
* lower motor neuron dz (sacral cord)
* Clinical features
* large, soft bladder
* +/- easy to express
* stranguria with minimal / weak stream
* large residual volume
* may see 'overflow' incontinence
30
LMN
* Sacral lesion, or lubar lesion
* Pelvic/Pudendal nerve
* trauma
* cauda equina syndrome
* distended, flaccid bladder
* easily expressed
* dec anal tone / dec perineal reflex
* +/- paraparesis / paralysis
31
Detrusor atony dx
Neurogenic vs. Non-neurogenic
* Neurogenic
* complete neuro exam
* imaging
* radiographs
* myelography
* CT/MRI
* Non Neurogenic
* don't forget rectal exam
* neuro exam
* imaging
* radiographs
* abdomen
* caudal urethra
* +/- contrast
* cytoscopy
32
detrusor atony - treatment
* neurogenic - fix underlying problem
* non-neurogenic
* relieve physical obstruction
* address functional obstruction
* internal sphincter
* external sphincter
* reestablish tight junctions
* keep bladder small
* stimulate detrusor contraction
* parasympathomimetic: **bethanechol**
* **don't do if urethral obstruction present**
33
Which class of drugs would relax the internal urethral sphincter?
* alpha-adrenergic antagonist
\*Beta receptors not really on neck of bladder or sphincters
34
Urethrospasm
* Relatively common post-catheterization
* especially in cats
* Clinical features
* stranguria, pollakiuria
* large, firm bladder
* initial normal stream then stops suddenly
* DX
* History
* Clinical signs
* catheterization: no evidence of obstruction
* +/- rads: **get the whole urethra**
* ****TX
* internal sphincter
* alpha antagonist
* phenoxybenzamine
* prazosin
* tamsulosin: **dogs only**
* external sphincter
* diazepam, alprazolam, midazolam
* acepromazine
35
Upper motor neuron lesion
* Lesion crania to S1
* tetra or paraparesis/paralysis
* hyperreflexia in pelvic limbs
* CP deficits in pelvic limbs
* Voluntary bladder function lost, pudendal n. intact
* sphincter intact: difficult to express
* +/- loss of inhibition
* DDX
* **IVDD**
* Trauma
* Neoplasia
36
Interneurons
* responsible for reflex arc
* pelvic n. intact, sense distension
* impulse can inhibit pudendal nerve and interneurons can travel down pelvic nerve to stimulate bladder contraction
* Some upper motor neuron dogs can develop a reflex bladder (neurogenic bladder)
* usually this will be incomplete emptying
* not conscious
37
Physical obstruction
* Clinical features
* stranguria, pollakiuria, +/- hematuria
* large, firm, painful bladder
* minimal-no urine passed
* +/- systemic signs
* vomiting, anorexia
* depression, recumbent
* relative bradycardia-check electrolytes
38
3 yo M-n DSH
lethargy and stranguria for 2 days
PE-large, firm, painful bladder, small amount red urine passed on PE
T: 101.5; P: 100; R: 60
* **This is an emergency**
* Check electrolytes
* address hyperkalemia
* Abdominal radiographs
* get whole urethra
39
Relieving physical obstruction
* Relieving physical obstruction
* catheterization is first choice
* and urethrogram to find obstruction
* cystocentesis
* consider risk of bladder rupture
* If no stones
* radioluscent stones, tumor, stricture
* contrast radiography or cystoscopy
40
Peripheral Nerve lesion
* **RARE NEVER RARE NEVER RARE**
* Hypogastric
* Pelvic =\> detrusor atony
* Pudendal =\> external sphincter dysfunction
41
2 yo, F-s labrador
PC: incontinence
What else do you want to know?
* When did it start/has it been there all along? - since a puppy
* When does she leak urine? - continuously
* Is she aware/does she posture normally? - no
* Can she urinate normally? - yes
* Stranguria/pollakiuria? - no
What next?
42
2 yo, F-s labrador
Incontinent
What do you want to do after PE?
disorder, ddx?
1. Watch urination - normal
* disorder: Storage dz
* top ddx: ectopic ureter
* USMI possible, don't usually leak all the time
* Pelvic bladder, also don't usually leak all the time
43
5 yo, M-c terrier
PC: unable to urinate
HX:
urethral obstruction 2 weeks ago, urethroliths flushed into bladder and removed, unable to urinate normally since then
PE:
soft, distended bladder, postures, stranguria
**WHAT WOULD YOU DO NEXT?**
**WHAT IS YOUR TOP DDX?**
1. Abdominal radiographs to see if there is a missed stone
* normal except distended bladder
2. Pass a urinary catheter to see if it passes easily
* catheter passes easily
* bladder easy to express when animal sedated
* Top DDX:
1. Detrusor atony: b/c of hx of obstruction and easily expressible bladder
2. Urethrospasm
3. Maybe both
44
Drug for treating Detrusor atony
* Bethanicol
* cholinergic
45
Phenylpropanolamine
* increases urethral sphincter tone
46
3 yo M-c DSH
unable to urinate, hx of urethral obstruction, indwelling catheter for several days, stranguria (passes small amount urine then stream abruptly stops), urinary cath passes easily, no stones on rads
**TOP DDX?**
**TX of choice?**
* Top DDX
* urethrospasm
* TX
* Phenoxybenzamine
* alpha antagonist to relax urethra and stop spasmings
