PRACTICAL: Clinical pathology and urinary tract infections

Question 1

What should you examine urine for before spinning?

Answer 1

APPEARANCE:

• turbidity
• colour
• odor

Question 2

Name 3 parts of urine examination

Answer 2

• gross appearance
• chemical analysis
• sediment analysis

Question 3

What does sediment analysis include?

Answer 3

• cellular elements
• crystals
• casts
• others

Question 4

What is urine pH?

Answer 4

• influenced by diet
• lower with high protein diets and fasting in herbivores
• higher pH with vegetable diet
• fresh sample essential (becomes alkaline on standing)

Question 5

Why does cystitis have a higher pH?

Answer 5

d/t conversion of urea to ammonia by bacteria

Question 6

T/F: pH may determine types of crystals formed

Answer 6

True

Question 7

4 types of proteinuria

Answer 7

• prerenal
• glomerular
• tubular
• haemorrhagi or inflammatory proteinuria (postrenal)

Question 8

When does glucose overspill occur?

Answer 8

• > 9mmol/L in dogs

- >14 mmol/L in cats

Question 9

What are the 2 types of glucosuria?

Answer 9

• hyperglycemic glucosuria (DM)

- renal glucosuria

Question 10

What do ketones suggest?

Answer 10

excessive fat degeneration (rather than using glucose as an energy source)

Question 11

What are the ketone bodies?

Answer 11

• acetoacetate (reagent strip primarily detects this)
• beta-hydroxybutyrate
• acetone

Question 12

When do you get ketonuria?

Answer 12

• poorly controlled diabetes

- starvation

Question 13

Causes - bilirubin in the urine

Answer 13

• when there are increased amounts:
• haemolytic anaemia
• liver disease with cholestasis
• gall bladder or bile duct obstruction

Question 14

Is the threshold for urine bilirubin higher or lower in cats or dogs? Importance?

Answer 14

lower in dogs: small amount (especially male) dogs not concerning, always significant in cats

Question 15

Appearance of urine with bilirubin

Answer 15

may appear bright yellow and stain surfaces

Question 16

Define haematuria

Answer 16

intact blood cells in urine. can see intact reds in sediment/ spun sample

Question 17

Ddx - haematuria

Answer 17

• trauma
• cystitis
• renal bleeding
• from GIT

Question 18

Define haemoglobinuria

Answer 18

contents of RBC in urine

Question 19

Ddx - haemoglobinuria

Answer 19

in haemolytic anaemias, where reds have broken down in stored urine

Question 20

Define myoglobinuria

Answer 20

mm oxygen carrying protein

Question 21

Ddx - myoglobinuria

Answer 21

severe mm damage

Question 22

Do you get RBC lysis in urine?

Answer 22

Yes - be careful with very dilute, alkaline urine let over time?????

Question 23

Outline examination of urine sediment

Answer 23

• quantify: cells, crystals, casts, bacteria
• bacterial morphology
• quantify casts/field at 10x
• quantify cells/ field at 40x (if >100/field then TNTC)

Question 24

What do WBCs in urine sediment indicate?

Answer 24

inflammation or infection (usually

Question 25

What doe RBCs in urine sediment indicate?

Answer 25

haemorrhage or contamination from cystocentesis (usually

Question 26

Describe ammonium biurate crystals

Answer 26

• neutral to alkaline pH

- dogs and cats with PSS

Question 27

Describe bilirubin crystal

Answer 27

• most common in canine urine
• low #s is not clinically significant in dogs
• often significant in cats, horses

Question 28

Describe calcium oxalate crystal

Answer 28

• any pH
• 2 forms: monohydrate - ethylene glycol toxicity OR dihydrate which can be found in normal urine
• horses can have low #s of these in urine

Question 29

Describe struvite crystals

Answer 29

• commonest crystal in dog and cat urine
• may be seen in normal urine
• neutral to alkaline pH

Question 30

Describe calcium carbonate crystals

Answer 30

• found in normal horse urine

Question 31

What are casts? significance?

Answer 31

• all casts are derived from renal tubular epithelium
• appearance depends on transit time down tubule
• high #s indicate tubular damage