Lecture 4

Question 1

When does the kidney dilute urine?

Answer 1

In the loops of henle

Question 2

When does the kidney concentrate the urine?

Answer 2

In the distal tubules and collecting ducts

Question 3

When would an inadequate USG show up in most species?

Answer 3

When 2/3 of functional nephrons are lost

Shows up before azotemia

Question 4

When does azotemia show up in most species?

Answer 4

When 3/4 of the functional nephrons are lost

Question 5

What is different in cats regarding inadequate USG?

Answer 5

Azotemia may show up before inadequate USG

Question 6

What is adequate USG for dogs?

Inadequate?

Answer 6

Greater than 1.030

Less than 1.030

Question 7

What is adequate USG for cats?

Inadequate?

Answer 7

Greater than 1.035

Less than 1.035

Question 8

What is adequate USG for large animals?

Inadequate?

Answer 8

Greater than 1.025

Less than 1.025

Question 9

What does hyposthenuria mean?

Answer 9

Kidneys can dilute urine but can’t concentrate it

Tubules are unresponsive to ADH

Question 10

What two things could cause hyposethenuria?

Answer 10

Central diabetes insipidus

Nephrogenic diabetes insipidus

Question 11

Describe isosthenuria

Answer 11

Osmolality of the urine is the same as plasma

Means the kidneys aren’t doing anything

1.008-1.012

Question 12

Where should the microscope condenser be when evaluating a urine sample

Answer 12

Turned down

“High and dry”

Question 13

What are normal values for epithelial cells, casts, WBCs, and RBCs?

Answer 13

Less than 5

Question 14

Squamous epithelium cells-

What do they look like?

Where do they come from?

When would you see them?

Answer 14

Large, flat

Lots of cytoplasm with small nucleus

Come from distal urethra, vagina, or prepuce

Seen with voided or catheterized samples and lower urinary tract contamination

Question 15

Transitional epithelial cells-

What do they look like?

Where do they come from?

When would you see them?

Answer 15

Round to pear shaped

Line urinary bladder and proximal urethra

Cystocentesis sample or other irritation in bladder

Question 16

Caudate epithelium-

What do they look like?

Where do they come from?

What do they mean?

Answer 16

Tadpoles

Originate from renal pelvis

Means pyelonephritis or calculi in renal pelvis

Question 17

Renal tubular epithelium-

What do they look like?

Where do they come from?

What do they mean?

Answer 17

Small round/ rectangular; may have vacuoles in the cat

Come from renal parenchyma

Mean damage in kidneys (inflammation, tubular nephritis)

Question 18

Hyaline casts

Answer 18

First step in cast formation

Protein matrix from secreted proteins from renal tubular epithelial cells

Low numbers are insignificant

Question 19

Epithelial (cellular) casts

Answer 19

Round to polygonal cells

Seen with nephritis/pyelonephritis (esp with low USG)

Comes after hyaline cast but before granular

Question 20

Granular casts

Answer 20

Seen with epithelial cells begin to degenerate

Indicates renal tubular damage

First are coarse granular then fine granular

Question 21

Waxy casts

Answer 21

Last stage

Indicates chronic tubular lesion

Question 22

What is the order of cast life?

Answer 22

Hyaline
Cellular
Coarse granular
Fine granular
Waxy

Question 23

Fatty casts

Answer 23

Will see lipid droplets in casts

Seen in cats or animals with hyperlipidemia

Question 24

Hemoglobin casts

Answer 24

Indicates IV hemolysis

Question 25

What might you mistake for casts?

Answer 25

Mucous threads, microscopic fibers

Tell the difference because the borders are undulating and not parallel (true casts)

Question 26

Calcium carbonate

Answer 26

Sphere or dumbell

Alkaline urine

Normal in horse, rabbit, guinea pig, elephant

Question 27

Struvite/ MAP

Answer 27

Rectangular prisms
Coffin lids
Alkaline urine
Secondary to UTI in dogs
Sterile cystitis in cats
Seen in stored samples

Question 28

Amorphous crystals

Answer 28

Found in clinically normal animals, looks like sand

Question 29

Urates/amorphous urates

Answer 29

Small brown spheroids

Acidic urine

Dalmations and english bulldogs are predisposed because of defective purine metabolism

Question 30

Uric acid

Answer 30

Found in avian and reptilian urine

Question 31

Calcium oxate- dihydrate

Answer 31

Envelope shape
Can be normal
Can be seen with cushings, storage, or eating oxalate containing plantes

Question 32

Calcium oxalate- monohydrate

Answer 32

Dumbbell- can be normal calciuresis

Picket fence- big deal! Ethylene glycol toxicity

Question 33

Ammonium biurate

Answer 33

Thorny apple looking

Sometimes will see in normal Dalmatians or english bulldogs

Indicates severe hepatic disease

Question 34

Bilirubin crystals

Answer 34

Needle like crystals

Can be normal in low numbers in dogs but always abnormal in cats

Indicates disorder in bilirubin metabolism (liver disease, EV hemolysis)

Question 35

Cystine crystals

Answer 35

Flat hexagons

Always abnormal

Indicates urolith

Breeds predisposed- dachshunds, english bulldogs, newfoundlands, siamese cats, chihuahuas, rottweilers

Question 36

Sulfa crystals

Answer 36

Haystack bundles or spheres

Seen in patients administered sulfa-containing drugs

Question 37

What do lipid droplets look like?

Answer 37

Green tint, refractile, variable in size

Question 38

When would any bacteria in the urine be abnormal?

Answer 38

If sample was obtained via cystocentesis

Question 39

What other nonbacterial organism might you find in the urine?

Answer 39

Fungi

• German shepherds with systemic aspergillosis
• candida
• animals on antibiotics or with indwelling catheters

Question 40

What parasitic organisms might you find in the urine?

Answer 40

Trichuris
Pearsonema
Dioctophyma renale

Question 41

Bladder neoplasia

Answer 41

Difficult to diagnose on urine sediment..may see abnormal transitional epithelium cells

Transitional cell carcinoma is most common (middle age-old dogs; not in cats)

Also wont see any inflammation