Equine clinical pathology

Question 1

Break the following word down into its different meanings: Panhypoproteinaemia

Answer 1

Pan = all
Hypo = reduced
Protein = protein
aemia = condition of the blood

Question 2

Break the following word down into its different meanings: leukocytosis

Answer 2

Leuko = white
cyt = cell
osis = disease

Question 3

Break the following word down into its different meanings: neutropenia

Answer 3

Neutro = neutrophil
penia = deficiency

Question 4

What is meant by a lab tests accuracy and precision?

Answer 4

How close is the result to the actual value?

How repeatable is the test? (if you took a sample and ran it 100 times, how close would all of the values be)

Question 5

Define the specificity and sensitivity of a test?

Answer 5

Specificity = % of disease negative animals that correctly identified as negative with your test
Sensitivity = % of disease positive animals that are correctly identified as positive with your test

Question 6

What are positive and negative predictive values?

Answer 6

PPV = % of positive results that are actually positive
NPV = % of negative results that are actually negative

Question 7

25-year-old Cob gelding with severe colic signs

- IF PCV has gone up where has the water gone?

Answer 7

Water has been lost from the blood into the bowel, so there is less water in the blood and PCV goes up

Question 8

What are the 2 main consequences of no blood supply to the bowel e.g. in a strangulating obstruction

Answer 8

• Anaerobic metabolism

- Ischaemic necrosis

Question 9

What is produced as the product of anaerobic metabolism aka an indicator of an anaerobically respiring bowel?

Answer 9

Lactate

Question 10

What can be measured to assess if ischaemic necrosis is occuring?

Answer 10

• Amount of RBCs and protein in the peritoneal fluid and blood (increased permeability of BVs causes leakage)

Question 11

How does peritoneal fluid change grossly to indicate a strangulated bowel?

Answer 11

Normal = yellowish colour

Changes to a reddish colour because of the RBCs

Question 12

What does SIRS stand for?

Answer 12

Systemic inflammatory response syndrome

Question 13

What are some of the effects of SIRS?

Answer 13

• margination of neutrophils
• activation of coagulation
• low blood pressure

Question 14

What are the consequences of low blood pressure in association to SIRS (think kidneys)?

Answer 14

• poor tissue perfusion
• reduced GFR
• increased creatinine and lactate

Question 15

Give definitions of the following:

• Haematology
• Cytology
• Histology

Answer 15

• morphology of blood and blood forming tissues
• cells, their origin, structure, function and pathology
• microscopic function and composition of tissues

Question 16

Blood comprises what % of BW?

Answer 16

10%

Question 17

What features make up the composition of blood?

Answer 17

• Plasma
• Erythrocytes
• Leukocytes
• Platelets

Question 18

How can serum and plasma be obtained from a blood sample?

Answer 18

Serum - allow blood sample to clot, centrifuge, take the fluid
Plasma - add an anticoagulant, centrifuge and take the fluid

Question 19

How is serum different to plasma?

Answer 19

Serum is plasma with the coagulation proteins removed

Question 20

What do we routinely measure a blood sample for when looking at red blood cells?

Answer 20

• Packed cell volume
• RBC count
• Haemoglobin concentration

Question 21

From the routine blood sample tests what values can be calculated?

Answer 21

• mean cell haemoglobin
• mean cell haemoglobin concentration
• mean cell volume

Question 22

How do the:
- Packed cell volume
- RBC count
- Haemoglobin concentration
Differ in hot blooded vs cold blooded horses?

Answer 22

Hot blooded have higher PCVs, RBC count and Hb conc

Question 23

Give examples of 3 blood proteins

Answer 23

Albumin
Globulin
Fibrinogen

Question 24

Which instrument is used to measure total protein?

Answer 24

Refractometer

Question 25

How would albumin and globulin appear on a serum protein electrophile, explain why

Answer 25

Albumin - small protein, low molecular mass, travels the furthest Globulin - larger protein, different globulins are spread out due to their different molecular masses

Question 26

What is the most common cause of hyperproetinaemia?

Answer 26

Dehydration

Question 27

What is the most common cause of hyperglobulinaemia?

Answer 27

Chronic inflammation

Question 28

What are 2 causes of hypoproteinaemia?

Answer 28

- aggressive intravenous therapy | - severe protein loss e.g. haemorrhage, diarrhoea

Question 29

Define oedema

Answer 29

Abnormal accumulation of fluid in interstitial spaces

Question 30

Define colloid osmotic pressure

Answer 30

The ability of blood to retain water

Question 31

Which 4 factors of the starling equation lead to odema?

Answer 31

- Increased hydrostatic pressure - Decreased colloid osmotic pressure - Increased permeability - Impaired lymphatic drainage

Question 32

A low level of ... on a blood sample, can be an indicator of oedema

Answer 32

Albumin

Question 33

What signs can a horse show that indicate a mild colic?

Answer 33

Quite Off feed Pawing ground

Question 34

Case: colic – 4-year-old Arab mare. 3 colics in the last 2 weeks, all resolved with NSAIDs - Physical exam mostly normal, gut sounds slightly reduced - The horse is showing mild signs - What are the next steps at the yard?

Answer 34

- Rectal exam - Nasogastric intubation - Blood and faeces sample - Give an NSAID to make the horse more comfortable

Question 35

What is the purpose of performing a nasogastric intubation for suspected colic? what is normal?

Answer 35

Can help indicate if there is a small intestine obstruction Should expect a small amount of fluid reflux from the stomach Can be up to 10-15L in a very sick horse

Question 36

What do you need to be aware of when looking at the blood results of a horse or cat?

Answer 36

Stress leucograms | - neutrophil levels raised slightly above normal

Question 37

If biochem results show low albumin levels and high globulin levels what does this indicate?

Answer 37

Chronic inflammation

Question 38

Case: horse that is unwilling/unable to move from a single spot, can pick up feet but not willingly - What are the possible causes?

Answer 38

- Sore joints, fracture (would expect to be weight bearing if it was affecting a singular limb) - Sore muscles - Neurological

Question 39

Case: horse that is unwilling/unable to move from a single spot, can pick up feet but not willingly - How could you detect if it is a myopathy (disease that affects muscles)?

Answer 39

Muscle enzymes – AST/CK, seen on a blood test | - When muscles are damaged they release these enzymes

Question 40

How are CK and AST levels affected if there is a myopathy?

Answer 40

CK - goes up very quickly, and comes down very quickly after an episode of myopathy AST - goes up more slowly and has a longer lag phase

Question 41

Why is CK more useful that AST in detecting a myopathy?

Answer 41

CK is only produced by muscles | AST is also produced by the liver so a rise in its level could indicate a liver problem

Question 42

Damage to hepatocytes in the liver causes what to be released?

Answer 42

Cytosolic enzymes

Question 43

What % of liver mass has to be lost before liver function is affected?

Answer 43

80%

Question 44

What are the signs of liver failure (seen on a test)?

Answer 44

Increased bile acid clinical signs: - decreased albumin - increased bilirubin - increased ammonia

Question 45

Despite being varied and non-specific what are some clinical signs of liver disease?

Answer 45

- weight loss - colic - anorexia - photosensitisation - diarrhoea - jaundice