Crystals

Question 1

Cholesterol

Answer 1

Flat
colorless plates
with corner notch (“Utah”)

• -acidic, neutral urine
• *may be normal in dogs & cats

Question 2

Calcium carbonate

Answer 2

Tiny
colorless
spheres or dumbbells

• -alkaline/neutral urine
• *common (normal) in rabbits, cows, and horses

Question 3

Calcium oxalate

Answer 3

Small
colorless
envelopes, dumbbell, & ring forms

• Dihydrate = can be normal (esp. plant diets); also in ethylene glycol toxicity
• *MONOhydrate = Specific for EG tox!

Question 4

Cystine

Answer 4

Flat
colorless
hexagonal plates

–acidic urine

Question 5

Leucine

Answer 5

Yellow
spheres
with concentric striations

–acidic urine

Question 6

Phosphates (ammonium, Mg)

Answer 6

3-6 sided
colorless prisms

**can be normal in dogs (± cats)
or
**associated with calculi

Question 7

Phosphates (Calcium)

Answer 7

Amorphous or long thin prisms

** common (normal) in dogs

Question 8

Tyrosine

Answer 8

Fine,
colorless or yellow needles
arranged in sheaves or rosettes

–acidic urine

Question 9

Urates (amorphous Ca, Mg, K)

Answer 9

Fine
yellow-red
amorphous granules

–acidic urine

Question 10

Urates (ammonium) / biurate

Answer 10

Yellow-brown spheres (“thorn apples”)

-alkaline urine!

**R/O disorders of ammonia metabolism
(shunts, liver mass)
**can be normal in Dalmatians

Question 11

Bilirubin granules/clusters

Answer 11

evaluate liver for cholestasis!!

Question 12

Uric Acid crystals

Answer 12

• common in Dalmatians, +/- other dogs.
• associated with altered purine metabolism
  (gout in man)

Question 13

Sulfa crystals

Answer 13

consider drugs for bizarre, colored crystals