Haematology (Yr 3)

Question 1

what is anaemia?

Answer 1

reduction of RBC mass below the reference values for PCV, RBC count or total Hb

Question 2

what are the three pathophysiological causes of anaemia?

Answer 2

inadequate production by bone marrow
increased destruction
loss (haemorrhage)

Question 3

what type of anaemia is usually seen with inadequate production by bone marrow?

Answer 3

non-regenerative
normocytic normochromic

Question 4

what type of anaemia is usually seen with increased destruction of RBCs?

Answer 4

regenerative
microcytic hypochromic

Question 5

what type of anaemia is usually seen due to haemorrhage?

Answer 5

not regenerative enough
microcytic hypochromic
(hypoprotainaemia also seen)

Question 6

how does the body respond to anaemia?

Answer 6

2,3-DPG increases in erythrocytes to give a lower oxygen-Hb affinity to allow better delivery to peripheral tissues
altering tissue perfusion
erythropoietin stimulates erythropoiesis
alterations to behaviour

Question 7

what are some clinical signs seen with anaemia?

Answer 7

pallor
weakness
exercise intolerance
tachycardia/tachypnoea
haemic murmur

Question 8

what are some possible findings on clinical examination of an animal with anaemia?

Answer 8

pallor
weakness
tachycardia/tachypnoea/dyspnoea
haemic murmur
icterus
petechiation
evidence of bleeding
pyrexia
lymphadenopathy
abdominal pain/mass or splenomegaly

Question 9

what are the ways anaemia can be classified?

Answer 9

severity (mild/moderate/severe)
erythrocyte index (MCV, MCHC)
regenerative response

Question 10

what is mild anaemia in dogs and cats?

Answer 10

30-36% dogs
20-24% cats

Question 11

what is moderate anaemia in cats and dogs?

Answer 11

18-29% dogs
15-19% cats

Question 12

what is severe anaemia in cats and dogs?

Answer 12

<18% dogs
<15% cats

Question 13

what is MCV?

Answer 13

mean corpuscular volume (size of RBC)

Question 14

what is MCHC?

Answer 14

mean corpuscular haemoglobin concentration (colour of RBC)

Question 15

how can MCV of an RBC be described?

Answer 15

microcytic
normocytic
macrocytic

Question 16

how can MCHC of an RBC be described?

Answer 16

hypochromic
normochromic

Question 17

how are polychromatophils stained?

Answer 17

diff quik

Question 18

how are reticulocytes stained?

Answer 18

new methylene blue

Question 19

what are two classic signs on haematology of regenerative anaemia?

Answer 19

reticulocytosis
polychromasia

Question 20

why do anaemias appear non-regenerative initially?

Answer 20

it takes 2-3 days for the reticulocyte count to increase

Question 21

is the percentage reticulocyte count of absolute reticulocyte count more accurate?

Answer 21

absolute

Question 22

what are the main causes of regenerative anaemia?

Answer 22

haemolysis
haemorrhage

Question 23

what are the two types of immature reticulocyte?

Answer 23

aggregate (24 hours)
punctate (up to 10 days)

Question 24

what causes hypovolaemic shock?

Answer 24

acute haemorrhage of all blood components

Question 25

why will PCV and TP continue to fall even after acute haemorrhage has been stopped?

Answer 25

interstitial fluid moves into the vascular space so replace the lost blood volume, diluting the proteins nd RBCs

Question 26

what is chronic blood loss?

Answer 26

continuous bleeding for >2 weeks

Question 27

what type of anaemia can develop in cases of chronic blood loss?

Answer 27

iron deficiency anaemia

Question 28

how regenerative is anaemia causes by chronic bleeding and iron deficiency?

Answer 28

initially is regenerative, will because less and less as the iron stones are used up

Question 29

what is the appearance of RBCs in cases of iron deficiency anaemia?

Answer 29

microcytic hypochromic

Question 30

what are some possible causes of iron deficiency anaemia?

Answer 30

chronic GI bleeding (most common) - NSAIDs, ulcers, neoplasia parasite infections congenital haemostatic defects dietary is rare

Question 31

how is iron deficiency anaemia treated?

Answer 31

treat underlying cause iron supplementation (oral ferrous sulphate) blood transfusion

Question 32

why should you be cautious when using iron dextrans IM injection to treat iron deficiency anaemia?

Answer 32

can cause anaphylaxis (is also painful)

Question 33

what are the two main categories of haemolysis?

Answer 33

immune mediated non immune mediated

Question 34

what are some non immune mediated causes of haemolysis?

Answer 34

oxidative damage (onions, paracetamol, zinc) intra-erythrocytic parasites mechanical damage (angiopathic anaemia)

Question 35

what happens during extravascular haemolysis?

Answer 35

antibody binds to RBC macrophages recognise RBC phagocytosis/lysis of RBC haem converted to bilirubin bilirubin is conjugated in the liver

Question 36

how do spherocytes form?

Answer 36

from partial phagocytosis of RBCs

Question 37

what happens is the livers capacity for conjugating bilirubin is overwhelmed?

Answer 37

hyperbilirubinaemia leading to bilrubinuria and jaundice

Question 38

what happens during intravascular haemolysis of RBCs?

Answer 38

intravascular cell lysis complement is activated\ haemoglobinaemia leading to haemoglobinuria and renal compromise

Question 39

why does intravascular haemolysis cause renal compromise?

Answer 39

the free haemoglobin leads to damage to tubular epithelium

Question 40

what are the possible clinical signs of intravascular haemolysis?

Answer 40

severe illness/sudden onset pallor collapse jaundice tachycardia/tachypnoea splenomegaly haemoglobinuria

Question 41

what are the signs on haematology of immune mediated haemolytic anaemia?

Answer 41

usually regenerative autoagglutination spherocytes leukocytosis with left shift

Question 42

what test can be used to diagnose IMHA?

Answer 42

Coombs

Question 43

what is the Coombs test?

Answer 43

confirms the presence of anti-RBC antibodies by causing agglutination of the RBCs if they have anti-RBC antibodies on them

Question 44

how do macrophages cause spherocytes to form?

Answer 44

partial phagocytosis leads to decreased RBC surface forming a discoid shape

Question 45

where should spherocytes be looked for on a smear?

Answer 45

in the monolayer (this is where you should look at RBC morphology)

Question 46

what could cause autoagglutination of RBCs?

Answer 46

antierythrocyte IgM (or very high IgG)

Question 47

what is the difference between agglutination and rouleaux formation?

Answer 47

agglutination is antibody mediated clumping that is strongly supportive of IMHA rouleaux formation is stacking of RBCs due to increased plasma proteins coating RBCs, caused by inflammation or cancer (normal in cats)

Question 48

how can you determine if a structure is a rouleaux formation or autoagglutination?

Answer 48

add saline to a drop of anti coagulated blood, the rouleaux formations will disappear

Question 49

what changes will be seen on biochemistry in IMHA cases?

Answer 49

elevated ALT and ALP hyperbilirubinaemia possible azotaemia

Question 50

what changes will be seen on urinalysis of IMHA cases?

Answer 50

haemolgobinuria bilirubinuria proteinuria

Question 51

what needs to be done before starting treatment for IMHA?

Answer 51

complete all diagnostic tests (immunosuppressants can mask underlying causes)

Question 52

what does IMHA treatment involve?

Answer 52

immuno-suppressive therapy antithrombotic therapy supportive therapy

Question 53

what would be the first choice drug for immunosuppressive therapy in IMHA?

Answer 53

prednisolone

Question 54

what are some side effects of corticosteroids?

Answer 54

PU/PD, polyphagia muscle wastage GI signs - gastritis, ulceration

Question 55

when would you consider using a second immunosuppressant in IMHA cases?

Answer 55

if clinical features of life threatening disease no response to corticosteroids over first 7 days if patient is at risk of severe side effects

Question 56

what is a salvage therapy for IMHA if immunosuppressants don't work?

Answer 56

immunoglobulins (human IVIG) that block macrophage receptors

Question 57

how long are IMHA animals typically on immunosuppressants?

Answer 57

4-8 months

Question 58

what can be used as antithrombotic therapy for IMHA cases?

Answer 58

antiplatlet drugs - clopidogrel anticoagulants - heparin

Question 59

what are some supportive therapies used for IMHA treatment?

Answer 59

blood transfusion gastroprotectants (omeprazole) if evidence of GI bleeding/ulcers

Question 60

what is neonatal isoerythrolysis?

Answer 60

destruction of neonates RBCs by maternal antibodies from colostrum

Question 61

what is microangiopathic haemolytic anaemia?

Answer 61

RBCs get mechanically damage as they pass through fibrin meshwork in the microvasculature, these damaged cells are then removed rapidly from circulation

Question 62

what are some possible causes of microangiopathic anaemia?

Answer 62

altered vasculature (haemangiosarcoma...) fibrin nets (DIC) glomerulonephritis congenital cardiac defects

Question 63

what are schistocytes?

Answer 63

fragmented RBCs

Question 64

what are some possible causes of acanthocytes?

Answer 64

liver disease (hepatic lipidosis) splenic haemangiosarcoma lymphoma high cholesterol diets

Question 65

what can cause oxidative injury to RBC?

Answer 65

paracetamol - cats onions, zinc - dogs

Question 66

why does oxidative injury to RBCs cause anaemia?

Answer 66

RBCs become more fragile so undergo haemolysis or are phagocytosed more readily

Question 67

what cell morphology is seen with oxidative damage to RBCs?

Answer 67

heinz bodies

Question 68

what are Heinz bodies?

Answer 68

round pale inclusions on the inner surface of RBC membrane due to denatured haemoglobin

Question 69

what animals is it normal to see some Heinz bodies in?

Answer 69

cats

Question 70

what is used to treat paracetamol poisoning in cats?

Answer 70

N-acetyl cysteine

Question 71

what type of anaemia is seen with Mycoplasma haemofelis?

Answer 71

regenerative

Question 72

how is Mycoplasma haemofelis treated?

Answer 72

doxycycline and prednisolone (cats will remain carriers)

Question 73

what can cause a non-regenerative anaemia?

Answer 73

primary/secondary marrow disease lack of erythropoietin (kidney disease)