Urolithiasis

Front 1

What is the precipitation-crystallization theory

Back 1

Urine is supersaturated w/ minerals and undergoes spontaneous precipitation (nucleation)

Front 2

What is the crystallization-inhibition theory

Back 2

Lack of crystallization inhibitors allow crystals/nucleus to form

i.e. GAGs, citrates, pyrophosphates

Front 3

What is the matrix-nucleation theory

Back 3

Preformed organic material promotes precipitation of minerals/crystals on surface, leading to a nucleus

i.e. pus, mucus

Front 4

What is the FB induction theory

Back 4

Hair, suture, and plant material can serve as surface for precipitation/nucleation
(rock candy forms faster if you put a string in it!)

Front 5

Explain how crystal growth occurs (broadly) once it has started

Back 5

A lower degree of supersaturation is needed for further mineral deposition once a nucleus is formed

Front 6

Explain epitaxial growth

Back 6

A nucleus of one type can promote organized crystal alignment of other types, leading to mixed stones

Front 7

What are the signs of LUT Uroliths

Back 7

LUT signs:
Stranguria
Hematuria
Pollakiuria

Systemic signs of renal failure if complete urethral obstruction

Front 8

True/False: Voiding urohydropropulsion can be therapeutic

Back 8

True

Front 9

How often should you use voiding urohydropropulsion in male cats

Back 9

Never!
Their urethral diameter does not support it

Front 10

Which urolith is the most common type in dogs

Back 10

Struvite and CaOx are equal

Front 11

What causes formation of struvites in dogs

Back 11

Likely precipitation-crystallization theory

Alkaline pH and supersaturation w/ Mg, NH4, and PO4 promote ppt

Induced by infection in most cases

Front 12

When urea is split by urease from urease-producing bacteria in the formation of struvites, and CO2 is produced, what type of stone can be formed

Back 12

Calcium carbonate stones

Front 13

What is another name for struvite stones

Back 13

Magnesium Ammonium Phosphate Stones

Front 14

How do you dx struvites in dogs

Back 14

pH ≥ 7
Inflammatory UA w/ bacteria
Culture usually + for Staph or Proteus
Radiodense and rounded

The bigger the stones get, the more likely they are to be struvites

Front 15

What is the dissolution protocol for struvites

Back 15

S/D for 1 mth
No treats
Abx 1 mth past resolution of signs
Rads q mth to check stone size (and UA and cultures)

Front 16

What is the avg time for struvite stones to dissolve

Back 16

Infection-induced: 3mths
Sterile: 1.5mths

Front 17

What characteristics of S/D make it a good diet to dissolve struvites

Back 17

Low protein to decrease urea and phosphate

Reduced in Mg

High in salt to dilute urine

High in fat to provide calories

Very acidifying

Front 18

What are three reasons for the use of surgical removal or lithotripsy in tx of struvites

Back 18

Owner cannot comply
Signs too severe to wait
Very unsure of stone type

Front 19

How can you prevent recurrent struvite formation

Back 19

Eliminate cause of recurrent infection

UA often to detect infection early (q3-6mths)

C/D or SO to decrease protein, Mg, and acidify

Increase water intake

Front 20

What is different about feline struvites

Back 20

They are rarely caused by UTI
They are the most common stone in cats
They are the most common component of mucus plugs

Front 21

How do you treat feline struvites

Back 21

Same as dogs
Most do not need Abx, though, b/c sterile
Therapeutic diet indicated for almost all b/c sterile

Front 22

What is the avg time for dissolution of feline struvites

Back 22

Infection-induced- 3mths
Sterile- 1mth

Front 23

What is the most common K9 nephrolith

Back 23

CaOx, but the occurence in the LUT is equal to that of struvites

Front 24

What is the most common cause of K9 CaOx LUT uroliths

Back 24

Idiopathic

Front 25

What gender are K9 CaOx crystals more common in

Back 25

Males

This is unlike struvites, which are more common in females

Front 26

How do you dx K9 CaOx stones

Back 26

Urine pH ≤ 7
Inflammatory, but usually sterile
Radiodense, irregular, sharp

Front 27

True/False: CaOx stones can be dissolved

Back 27

False

Front 28

What is the recurrence rate for CaOx formers

Back 28

40-50% recurrence for idiopathic

Front 29

How do you treat CaOx stones

Back 29

Increase water intake
Maintain pH 6.5-7.5
Maintain USG <1.020

Front 30

What is the most common UUT stone in the cat

Back 30

CaOx

Front 31

What is the best diet for prevention of canine CaOx stones

Back 31

SO or u/d (restricted calcium and oxalate, moderately reduced protein, and neutral pH inducing)

Front 32

How frequently should UAs be monitored when aiming to prevent future CaOx stones in dogs

Back 32

q 3-6mths in recurrent formers

Front 33

What is one reason for the increase in the amt of CaOx stones seen in cats

Back 33

Struvite-prevention diets

Other reasons:
Dry food
Modification of maintenance diets

Front 34

How do you treat and prevent CaOx stones in cats

Back 34

Same as dogs

Treat:
Surgical removal
Voiding urohydropulsion
Laser lithotripsy
Eliminate any concurrent infection

Prevent:
Keep pH 6.5-7.5 and USG <1.030
c/d or SO to decrease protein

Front 35

Why are ammonium urate stones formed in Dalmatian dogs

Back 35

They have impaired transport of uric acid across hepatocytes and renal tubular epithelium
Leads to hyperuricuria
(only few form stones, though)

Front 36

Besides Dalmatian breed anomalies, what are other reasons that dogs develop ammonium urate stones

Back 36

PSS, MVD (portovascular anomalies)
Urease-producing bacteria

Front 37

Which gender are ammonium urates more common in

Back 37

Males
(far more common in)

Front 38

How do ammonium urate stones appear on rads

Back 38

Are usually radiolucent
U/S or contrast usually req'd

Front 39

What is the pH of urine in cases w/ ammonium urates

Back 39

Usually neutral to acidic

Front 40

What is the dissolution protocol for ammonium urates

Back 40

Low purine, alkalinizing diet (u/d)

Allopurinol (XO inhibitor to keep xanthine from becoming uric acid)

Urine alkalinizing agents if urine still acidic despite u/d

Monitor urine, contrast rads or U/S monthly

Front 41

How long does it typically take to dissolve ammonium urate stones

Back 41

Several months

Front 42

How can ammonium urate stones be prevented

Back 42

u/d or k/d
Increased H2O consumption
(want USG <1.020)
pH>7
Low dose Allopurinol

Front 43

How can you dissolve feline ammonium urates

Back 43

There is no effective protocol b/c these animals are obligate carnivores and need the protein in their diet

Front 44

How does laser lithotripsy work

Back 44

Laser generates heat within a urolith, causing thermal decomposition and boiling with fragmentation due to H2O vaporization

Front 45

Which animals are NOT considered good candidates for laser lithotripsy

Back 45

Male dogs smaller than 15lbs

Male dogs w/ stones bigger than 5-9mm

Females (cats and dogs) w/ bladder full of stones

All male cats!

Front 46

How common are UUT stones, and what is the most common type

Back 46

Far less common than LUT ones

CaOx most common, then struvite

Front 47

What are the typical signs of UUT stones

Back 47

None usually

But, CRF common in cats (hard to tell which came first)

Front 48

How often is sx utilized as tx for nephroliths

Back 48

Not often b/c difficult to perform and many complications common

Front 49

When is nephrotomy/ ureterotomy indicated

Back 49

Urolith is source of recurrent UTI or sepsis

Renal pelvic/diverticular obstruction

Declining renal fxn w/ persistent nephrolith

Enlarging stone despite therapy

Patient is symptomatic (pain)

Front 50

What is the recurrence rate for UUT stones

Back 50

High

Front 51

When can ESWL be used in cats

Back 51

Never (too traumatic)