Equine clinical pathology Flashcards
Break the following word down into its different meanings: Panhypoproteinaemia
Pan = all Hypo = reduced Protein = protein aemia = condition of the blood
Break the following word down into its different meanings: leukocytosis
Leuko = white cyt = cell osis = disease
Break the following word down into its different meanings: neutropenia
Neutro = neutrophil penia = deficiency
What is meant by a lab tests accuracy and precision?
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)
Define the specificity and sensitivity of a test?
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
What are positive and negative predictive values?
PPV = % of positive results that are actually positive NPV = % of negative results that are actually negative
25-year-old Cob gelding with severe colic signs
- IF PCV has gone up where has the water gone?
Water has been lost from the blood into the bowel, so there is less water in the blood and PCV goes up
What are the 2 main consequences of no blood supply to the bowel e.g. in a strangulating obstruction
- Anaerobic metabolism
- Ischaemic necrosis
What is produced as the product of anaerobic metabolism aka an indicator of an anaerobically respiring bowel?
Lactate
What can be measured to assess if ischaemic necrosis is occuring?
- Amount of RBCs and protein in the peritoneal fluid and blood (increased permeability of BVs causes leakage)
How does peritoneal fluid change grossly to indicate a strangulated bowel?
Normal = yellowish colour
Changes to a reddish colour because of the RBCs
What does SIRS stand for?
Systemic inflammatory response syndrome
What are some of the effects of SIRS?
- margination of neutrophils
- activation of coagulation
- low blood pressure
What are the consequences of low blood pressure in association to SIRS (think kidneys)?
- poor tissue perfusion
- reduced GFR
- increased creatinine and lactate
Give definitions of the following:
- Haematology
- Cytology
- Histology
- morphology of blood and blood forming tissues
- cells, their origin, structure, function and pathology
- microscopic function and composition of tissues
Blood comprises what % of BW?
10%
What features make up the composition of blood?
- Plasma
- Erythrocytes
- Leukocytes
- Platelets
How can serum and plasma be obtained from a blood sample?
Serum - allow blood sample to clot, centrifuge, take the fluid
Plasma - add an anticoagulant, centrifuge and take the fluid
How is serum different to plasma?
Serum is plasma with the coagulation proteins removed
What do we routinely measure a blood sample for when looking at red blood cells?
- Packed cell volume
- RBC count
- Haemoglobin concentration
From the routine blood sample tests what values can be calculated?
- mean cell haemoglobin
- mean cell haemoglobin concentration
- mean cell volume
How do the: - Packed cell volume - RBC count - Haemoglobin concentration Differ in hot blooded vs cold blooded horses?
Hot blooded have higher PCVs, RBC count and Hb conc
Give examples of 3 blood proteins
Albumin
Globulin
Fibrinogen
Which instrument is used to measure total protein?
Refractometer
How would albumin and globulin appear on a serum protein electrophile, explain why
Albumin - small protein, low molecular mass, travels the furthest
Globulin - larger protein, different globulins are spread out due to their different molecular masses
What is the most common cause of hyperproetinaemia?
Dehydration
What is the most common cause of hyperglobulinaemia?
Chronic inflammation
What are 2 causes of hypoproteinaemia?
- aggressive intravenous therapy
- severe protein loss e.g. haemorrhage, diarrhoea
Define oedema
Abnormal accumulation of fluid in interstitial spaces
Define colloid osmotic pressure
The ability of blood to retain water
Which 4 factors of the starling equation lead to odema?
- Increased hydrostatic pressure
- Decreased colloid osmotic pressure
- Increased permeability
- Impaired lymphatic drainage
A low level of … on a blood sample, can be an indicator of oedema
Albumin
What signs can a horse show that indicate a mild colic?
Quite
Off feed
Pawing ground
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?
- Rectal exam
- Nasogastric intubation
- Blood and faeces sample
- Give an NSAID to make the horse more comfortable
What is the purpose of performing a nasogastric intubation for suspected colic? what is normal?
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
What do you need to be aware of when looking at the blood results of a horse or cat?
Stress leucograms
- neutrophil levels raised slightly above normal
If biochem results show low albumin levels and high globulin levels what does this indicate?
Chronic inflammation
Case: horse that is unwilling/unable to move from a single spot, can pick up feet but not willingly
- What are the possible causes?
- Sore joints, fracture (would expect to be weight bearing if it was affecting a singular limb)
- Sore muscles
- Neurological
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)?
Muscle enzymes – AST/CK, seen on a blood test
- When muscles are damaged they release these enzymes
How are CK and AST levels affected if there is a myopathy?
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
Why is CK more useful that AST in detecting a myopathy?
CK is only produced by muscles
AST is also produced by the liver so a rise in its level could indicate a liver problem
Damage to hepatocytes in the liver causes what to be released?
Cytosolic enzymes
What % of liver mass has to be lost before liver function is affected?
80%
What are the signs of liver failure (seen on a test)?
Increased bile acid clinical signs:
- decreased albumin
- increased bilirubin
- increased ammonia
Despite being varied and non-specific what are some clinical signs of liver disease?
- weight loss
- colic
- anorexia
- photosensitisation
- diarrhoea
- jaundice
