Urolithiasis (Specht) Flashcards
1
Q
urolith formation
A
- Initiation requirements
- supersaturation
- precipitation
- nucleation
- Less saturation required for growth
- direct growth slow process
- aggregation can occur quickly
2
Q
Stones probably result from
A
- Nucleation + Growth + Aggregation
*aided by retention
3
Q
Factors influencing precipitation
A
- Solute conc
- pH
- other ions
- proteins, inhibitors
- surfaces present
- bacteria
4
Q
struvite, aka
A
magnesium ammonium phosphate
5
Q
Most common stones we see in small animal
A
Calcium Oxalate (CaOx)
6
Q
Stones caused typically due to inc solute conc
A
- struvite, urate, cystine
7
Q
Stones typically caused by lack of other ions, inhibitors
A
- Calcium oxalate
8
Q
Urolith composition
A
- Mineral (crystalline component)
- many kinds: struvite, CaOx, urate, etc
- very imp for planning/prevention
- Matrix (not very well understood)
- proteins, GAGA, etc
- Role is uncertain
9
Q
Crystalluria
A
- means supersaturated urine
- risk of urolith formation
- may help predict urolith type: diet changes, UTI’s, etc
- Crystals don’t mean uroliths
- Crystals don’t equal pathology
- Crystals may be artifactual due to cooling
10
Q
When uroliths are imp
A
- hematuria, pyuria
- urgency, stranguria, pollakiuria
- 2nd bact infections
- obstruction
-
How important
- in this patient….
- at this time….
11
Q
Diagnosis
A
- Presence suspected based on
- Hx & PE
- UA
- Diagnosed by imaging
- rads
- US
- Contrast studies
- for radioluscent stones
- Endoscopy
12
Q
Order of radioopaqueness (most to least)
A
- CaOx
- Struvites
- Cystein
- Urates
- can sometimes still be seen on rads: big ones or with other minerals
13
Q
Additional stone info
A
- Number
- Size
- Location
- Risk factors & concurrent dz
14
Q
Definitive dx
A
- mineral analysis
- Minnesota: free, takes longer
- UC Davis: faster
15
Q
Treatment
A
- urethral or bilateral ureteral obstruction is life-threatening
- acidosis
- hyperkalemia
- initial tx: fluids
- IV cath before U cath
- If K+ and A-B status are safe then relieve obstruction
- comatose cat: doesn’t need sedation/anesthesia
- if a cat can right itself: need sedation/anesthesia
- palpate penis (cats) => might be able to express if in penis
- rectal palpation in dogs
- catheterization => retrograde
-
Don’t forget lube
- in cath and in flush solution
- +/- decompressive cysto
- Urinary diversion
- Laser lithotripsy
- surgery if necessary
- ureteral stone removal
- perineal urethrostomy
16
Q
Medical therapy
Dissolution: struvite/urate
A
- Some stones don’t dissolve
- we may not know what kind of stone is there
- stones must be in bladder (bathed in urine)
- risk of obstruction
- small risk
- Risk of worsening problem if we guess wrong
- also small risk
- Usually accomplished with diet
- reduce solute conc
- modify urine pH
- alter pop of other ions
- Antibiotics if UTI present (complicated UTI)
- until stone is out of body
- +/- pH modulation
- other meds (allopurinol in dalmations, methionine)
- requires long-term plan for re-checks
- compliance
- follow-up
17
Q
Catheter removal
A
- may work for very small calculi
- procedure
- cath tip at trigone
- patient help upright (bladder neck down)
- bladder agitated and emptied
- refill and repeat
*not a ton of presenting complaints that are conducive to this procedure
18
Q
Urohydropropulsion
A
- general anesthesia
- catheter used to fill bladder w/saline then removed
- patient held upright
- agitate then let settle
- express to achieve forceful stream
- collect for exam
- repeat until all stones collected
- All stones less than urethral diameter
- < 5 mm
- better with smooth surface stones
- be ready unobstruct or go to sx
- rupture
- obstruction
- Useful for stone recurrance (small stones usually)
19
Q
Cystoscopic retrieval
A
- generalized anesthesia
- utilization of
- emtpty sheath
- stone baskets
- Ellik evacuator
- can get a little bigger stone than voiding
20
Q
Lithotripsy
A
- Fragmentation of stone in vivo
- less invasive than sx
- not much cheaper tho
- several methods
21
Q
Lithotripsy
ESWL
A
- shcok waves generated outside of body
- precisely targeted
- primarily useful when uroliths are fixed in location
- nephroliths/ureterliths
- can cause ureteral obstruction
- limited availability
22
Q
lithotripsy
laser
A
- intracorporeal (laser) lithotripsy
- holmium - YAG laser
- quickly attenuates in fluid
- proximity/contact to uroliths required
- will damage bladder wall if comes in contact
- most common for cystic calculi
- at UF this is cheaper than sx
- opposite from private practice
- better for single stone or few small stones
- better for female dogs
- not feasible for small male dogs
23
Q
Surgery
A
- Most common
- be aware of residual stones
- invasive, but normally good outcome
- laparascopic-assisted?
- better for lower tract
- more complications with upper tract
- easy to leave stones behind
24
Q
Preventative strategy
consider in….
A
- consider in
- recurrent urolithiasis
- nephrolithiasis, ureterolithiasis
- no identifiable underlying cause
- underlying cause untreatable or uncontrolled
25
Q
Non-specific prevention
A
- inc H2O consumption
- dec mineral conc
- reduced possibility of super saturation
- strategies
- available fresh water
- canned food
- dry food with water
- decrease urine retention/inc access to outdoors
26
Q
Struvite stones
A
- common in dogs
- often assoc with UTI’s
- may respond to dissolution
- In cats usually no assoc UTI
- Usually do to super saturation events
- liver dz - inc ammonia
- change in mg
- kidney dz - change in phosphate levels
- Diet: lower mineral conc, pH modulation
- slight risk of inc CaOx risk
- pH modulation: acidifiers not usually necessary, may help assess other tx
- Abx if UTI for as long as stones are present
27
Q
Calcium Oxalates
A
- can’t be dissolved, complicated and poorly understood
- 30-50% recurrence w/in 3 yrs
- Risk factors
- breed: schnauzers
- inc Ca
- obesity
- primary hyperparathyroidism
- chronic metabolic acidosis
- Diet: something about moderate pH
- Hills u/d; royal canin S/O
- Hill’s w/d
- pH modulation
- pushed to alkaline range
- Hydrochlorathiazide
- Potassium Citrate
28
Q
Hydrochlorothiazide
A
- dec Ca excretion
- consider using if diet fails
29
Q
Potassium Citrate
A
- 2 potential actions
- pH modulation
- correction of hypocitraturia
- Cosider when
- diet, thiazides have failed
- to achieve target pH
