Urinalysis

Question 1

When should u+ be examined

Answer 1

As soon as possible
Within 60 mins fresh, or refridgerate then allow to come back to room temp before analysis
Longer age of u+ = higher pH, degeneration of cells and casts, dissolution and precipitation of casts, bacteria multiply, decrease in glucose and ketones

Question 2

How may infection alter pH

Answer 2

Increases it

Question 3

Outline the protein measurement on dipstick

Answer 3

Small amount normal, can get false positives if the pH is high
Only albumin so will miss things like bence jones proteins

Question 4

What can cause false readings on the blood measurement on dipstick?

Answer 4

bleach and bacteria

Question 5

What can cause a +ve on the blood measurement on dipstick?

Answer 5

UT disease
Genital tract disaese
Prostate disease
coagulopathy

Question 6

Outline the leukocyte measurement on dipstick

Answer 6

If negative means nothing
If +ve in dogs is significant
Cats can get false +ve

Question 7

How can you get a false +ve glucose measurement on dipstick?

Answer 7

Bleach/ from containers
Also from drugs - asprin/ morphine/ vitamin c/ cephalosporins
False -ve - from fridge samples

Question 8

Whaat does glucosuria mean?

Answer 8

If also high in blood - DM or stressed cat or exogenous/ endogenous steroids
If normal in blood - fanconi syndrome or primary renal glucosuria

Question 9

What can cause high ketones measurement on dipstick?

Answer 9

Diabetic ketosis
starvation
high T4
Can just be if the sample is very concentrated

Question 10

What must you be careful with with measuring ketones on dipstick with DKA?

Answer 10

In severe cases it is main bHB that is produced, this is not measured on the dipstick, only acetoacetate.
So as patient improves their ketone levels on dipstick may increase

Question 11

On sediment, what does a lot of RBCs without lots of WBCs suggest?

Answer 11

Haemorrhage without significant inflammation
e.g. Neoplasia
Trauma
Coagulopathy

Question 12

What may bacteria in sediment without inflammation suggest?

Answer 12

May be precipitate/ contamination

May also occur in cushings and renal disease - ideally culture

Question 13

When do granular casts occur?

Answer 13

nephrotoxicity
Ischaemia
Haemoglobinuria
Small amount may be normal

Question 14

When are crystals more likely to be significant?

Answer 14

If examined within 60 mins of sample collection
Dilute urine
Blood or WBCs present
Suggestive clinical signs

Question 15

Outline struvite stones/ crystals

Answer 15

Coffin lid shape, colourless
radio-opaque
magnesium ammonium phosphate
Alkaline pH
Can occur in infection due to urease producing bacteria, can also be in sterile u+
UTI ones with dogs, sterile with cats normally
f>m
Can be normal
Stones are round, smooth and dense
Staph/ e.coli/ klebsiella/ proteus

Question 16

Outline calcium oxalate crystals

Answer 16

Neutral to acidic urine
Colourless
Envelope shape (dihydrate)
Monohydrate are longer in shape, 
occur in antifreeze poisoning
Need surgery to remove uroliths
Radio-opaque
Stones can cause a UTI
Males more than females
Dogs that urinate less are more at risk of stones
Stones are round to oval, smooth or rough

Question 17

Outline calcium phosphate aka apatite

Answer 17

Radio-opaque
Neutral to weakly acidic or alkaline urine
Can be normal
Can be due to underlying hypercalcaemia
1-2% uroliths
Pure or minor component of Ca Ox or struvite
Lots of forms reported
More in kidneys than the bladder

Question 18

Outline Ammonium urate

Answer 18

Common in dalmations and English bulldogs, also russian terrier, mini shnauzer, Shih Tzus, yorkies
In other breeds should look for liver disease or PSS
Stones lucent or only barely visible
In acid urine
stones are smooth round to oval
cats can get idiopathic ones

Question 19

Outline bilirubin crystals

Answer 19

Can be normal in dogs, not cats
can suggest liver diease
acidic urine
N.B the dipsticks are more sensitive to conjugated bilirubin than unconjugated bilirubin

Question 20

Outline cholesterol crystals

Answer 20

Rare
Neutral to acidic urine
Can be normal but can be due to a PLN

Question 21

Outline cystine crystals

Answer 21

Rare
Hexagons
Acidic urine
Seen in Mastiffs, EBDs, dachshunds, chihuahuas due to abnormal metabolism. Autosomal recessive in newfoundlands, can occur v early
Stones radiolucent with slightly irregular shape
Crystals predisposing but not a cause

Question 22

What is UPCR?

Answer 22

Urine protein divided by urine creatinine
Quantifies protein loss
Only useful if there is no sediment
>0.5 in dogs and >0.4 in cats = abnormal

Question 23

Outline microalbunuria

Answer 23

Newish test, can be an early indicator of renal disease but can also go up with other issues.

Question 24

How can you tell what is causing brown red or black urine?

Answer 24

If the urine is discolored because of myoglobin, the plasma is clear because myoglobin in plasma is not bound significantly to a carrying protein, which results in filtration and excretion of myoglobin.
If the plasma is pink, it is suggestive of haemoglobin. If the plasma is yellow, it is suggestive of bilirubin; serum bilirubin concentration should also be increased.

Question 25

What do haemoglobinuria/ myoglobinuria/ bilirubinuria mean?

Answer 25

Myoglobinuria indicates muscle damage; serum creatine kinase activity is often increased Hemoglobinemia indicates intravascular hemolysis resulting from immune-mediated, parasite-mediated, or drug-mediated destruction of RBCs. Hyperbilirubinemia may result from liver disease, post–hepatic obstruction, or hemolysis.

Question 26

What does milky white urine suggest? How can you differentiate the causes?

Answer 26

presence of WBCs (pyuria), lipid, or crystals. | Examine the sediment

Question 27

What are the differentials for proteinuria?

Answer 27

prerenal (fever, strenuous exercise, seizures, extreme environmental temperature, and hyperproteinemia) renal (primarily glomerular and occasionally tubular disease), postrenal (inflammation, hemorrhage, and infection)

Question 28

How many WBCs should be seen phpf?

Answer 28

Normal urine should contain less than 5 WBCs per field at 400× magnification

Question 29

How many RBCs should be seen per hpf?

Answer 29

Normal urine should contain less than 5 RBCs per field at 400× magnification

Question 30

What are hyaline casts?

Answer 30

``` pure protein precipitates transparent have parallel sides and rounded ends, composed of mucoprotein. They may occur with fever, exercise, and renal disease, odd one can be normal ```

Question 31

Which casts are always abnormal and what do they mean?

Answer 31

erythrocyte casts and WBC casts Erythrocyte casts form because of renal hemorrhage. WBC casts occur because of renal inflammation, as with pyelonephritis.

Question 32

What is Brownian Motion?

Answer 32

Random movement of the granules in a neutrophil - can be mistaken for bacteria

Question 33

Outline granular casts

Answer 33

degraded cellular material from injured renal tubular epithelial cells or, less often, inflammatory cells, embedded in a protein matrix. Nephrotoxins (e.g., gentamicin sulfate, amphotericin B), nephritis, and ischemia are pathologic events that result in their formation.

Question 34

How are struvites formed in a UTI? More tha 50% fo stones are struvite Almost always due to a UTI in dogs

Answer 34

Urease split to urea and bicarb Urea to ammonia to ammonium = increase in pH as loss of H+ lower H+ --> increased production of phosphorous which combines with Mg Bicarb --> increased pH = lower solubility of struvite Ammonium leads to damage of urothelial GAG coating which allows bacteria and struvite to attach This leads to the promotion of the formation of an organic matrix leading to struvite stones **when disolving, bacteria can be trapped in stones leading to the cycle again**

Question 35

Outline the process of purine to allantoin

Answer 35

Purine to hypoxanthine through xanthine oxidase, to xanthine through XO again to uric acid through uricase, to allantoin

Question 36

Why are dalmations predisposed to urate calculi?

Answer 36

Decreased conversion of uric acid to allantoin Increased uricosia d/t decreased tubular absoprtion males more than females Average age 4.5, decreasing chace with age Autosomal recessive

Question 37

What can cause urate stones?

Answer 37

Urease bacteria = ammonium, which predisposes to urate calculi formation. needs low pH Low protein diet - poor hepatic function - increased uric acid Poor hepatic function (MD, pSS, cirrhosis)

Question 38

outline xanthine uroliths

Answer 38

Tx with allopurinol, diet high in purine | Hereditary in dachshunds and CKCS