5: Haematology 3 Flashcards
What are some primary causes of secondary haemolytic anaemia?
Neoplasia, drugs, alloimmune
What are two non-immune mediated causes of haemolytic anaemia?
Oxidative damage, envenomation
Which sex and breed usually get IMHA?
Female Cockers, not cats
What’s the normal cause of IMHA?
Idiopathic
What are four drugs that can cause IMHA?
NSAIDs, cephalosporins, sulphonamides, vaccinations
What are three infectious agents that can cause IMHA?
Babesia, Leishmania, FeLV
Which antibodies are produced in IMHA?
IgG/M
What happens to the RBCs following recognition by macrophage Fc receptor?
Either fully destroyed or form a spherocyte following removal of part of the membrane
Other than IMHA, what other conditions can cause spherocytosis?
Zn toxicity, envenomation, PFK deficiency
When can spherocytosis be artefactual?
In tail of the smear
Why can’t you see spherocytosis in cats?
Their blood cells don’t have central pallor
In which species in Rouleaux normal?
Cats and horses
How do you tell apart Rouleaux vs agglutination?
Rouleaux will disperse in saline, agglutination won’t
WHen doing an agglutination test for IMHA, what must you do to remove other causes of agglutination?
Wash cells and do it again to remove other causes
What is the definitive test for IMHA?
Coombs test
How do you treat idiopathic IMHA?
High dose pred or cyclosporin or azathioprine
How do you treat the hypercoagulable state in IMHA?
Aspirin, transfusion, anti-thrombin therapy
How can you remove the problem macrophages in IMHA?
Splenectomy
Which species gets haemolytic anaemia due to haemotropic mycoplasmas?
Cats
Which species gets haemolytic anaemia due to Babesia?
Dogs and cattle
Which species gets haemolytic anaemia due to Leptospirosis?
Cattle, lambs, pigs
Which species gets haemolytic anaemia due to Clostridium?
Ruminants, horses
Which species gets haemolytic anaemia due to equine infectious anaemia virus?
Horses
How many species of haemolytic mycoplasmas are there?
4
What is the most common species of haemolytic mycoplasma?
M. heamofelis
Which part of the cell to haemolytic mycoplasmas attach to?
Cell membrane
Which kind of haemolysis does haeotropic mycoplasma cause?
Extravascular
What duration of parasitaemia does haemotrpic mycoplasma cause?
Cyclical
How do you test for haemotropic mycoplasma?
Hard to see on blood smear so use PCR
Which kind of cats are most likely to get haemotropic mycoplasma?
FeLV infected
What kind of parasite is babesia?
Intracellular protozoan
How is babesiosis spread?
Tick
Which kind of haemolysis does babesiosis give?
Extravascular or intravascular +/- IMHA
How do you diagnose babesiosis?
Can see on capillary blood smear but PCR is best
What are two examples of alloimmune haemolysis?
Transfusion reactions and neonatal isoerythrolysis
What causes neonatal isoerythrolysis?
Ingest antierythrocyte antibodies from colostrum
What is the most relevant dog blood group?
DEA1.1
How many times can you transfuse a dog without cross-matching?
Once
How do DEA1.1 dogs get alloantibodies?
From transfusion reaction or pregnancy/parturition of a positive pup
What are the three cat blood groups?
A (weak anti-B), B (strong anti-A), AB (no reaction)
When must you especially cross match in cats?
Type A given to type B
What happens if a type B cats has type A kittens?
Neonatal isoerthyrolysis from colostrum
How can you prevent neonatal isoeryhtrolysis in kittens?
Pre-breeding blood typing
What is formed by oxidation of haemoglobin chains?
Heinz bodies
Oxidant damage to what leads to eccentrocytes?
RBC cell membrane
How is methaemoglobin formed?
Oxidation of Fe3+ to Fe2+
What stain is used to see Heinz bodies?
Methylene blue
Which kind of haemolysis are Heinz bodies associated with?
Intra or extravascular
What are four toxins that can result in Heinz bodies?
Onions, garlic, paracetamol, zinc
In which species can Heinz bodies be normal?
Cats
Which other diseases can cause Heinz bodies?
Liver disease, diabetes, hyperthyroidism, recent propofol
Which conditions can cause erythrocyte fragmentation?
Abnormal vessels e.g. haemangiosarcoma, fibrin clots, valvular disease
Which kind of cells are formed by erythrocyte fragmentation?
Acanthocytes and schistocytes
Why do you get mild anaemia following acanthocyte and schistocyte production?
Removed by spleen
Which breeds are prone to PK deficiency?
Various
What is degree of anaemia and prognosis like in PK deficiency?
Severe regenerative, poor prognosis
Which breeds are prone to PFK deficiency?
Cocker
What is degree of anaemia and prognosis like in PFK deficiency?
Mild, regenerative, good prognosis
Why is PFK deficiency worse with hyperventilation?
Shows “alkaline fragility”
When does hypoP commonly occur?
Following insulin or post-parturient
What kind of haemolysis does hypoP cause?
Intravascular
Why does hypoP cause haemolysis?
Reduces ATP so can’t maintain membranes so more likely to be haemolysed
Which cells are reduced in aplastic anaemia?
Pancytopaenia
What is happening to bone marrow in aplastic anaemia?
Marrow stem cells are replaced by fat
What are the three causes of an aplastic anaemia?
Infection (parvo, FeLV), drugs (oestrogen, bute), immune mediated
Why do leucopaenia and thrombocytopaenia precede anaemia in aplastic anaemia?
Shorter cell life span
What is another name for pure red cell aplasia?
Intramedullary IMHA
Which cells are damaged in pure red cell aplasia?
Erythroid precursors only
What is the normal cause of pure red cell aplasia?
Immune-mediated
What kind of anaemia do you see in pure red cell aplasia caused by FeLV?
Macrocytic
What are cells in bone marrow doing in pure red cell aplasia?
Erythroid hypoplasia or maturational arrest
Which kind of -penias does luekaemia cause?
Anaemia, neutropenia, thrombocytopenia
Other than in leukaemia, which other neoplasias can replace bone marrow cells?
Stage V lymphoma in dogs, histiocytic sarcoma, mammary or mast cell
Which cells lines are reduced in myelofibrosis?
Anaemia only
What is an example of a disease myelofibrosis can be secondary to?
IMHA
How well do cells exfoliate in myelofibrosis?
Not well
How do you diagnose myelofibrosis?
Bone marrow core biopsy
WHat is the most common cause of secondary non-regenerative anaemia?
Anaemia of inflammatory disease
How long must inflammatory disease be present to cause anaemia?
A long time
What do WBCs look like on CBC in anaemia of inflammatory disease?
Inflammatory leucogram
WHat three processes cause anaemia in inflammatory disease?
Increased hepcidin (decreased Fe absorption), shortened RBC survival (oxidative injury), blurred release and response to EPO
What three processes cause anaemia in CKD?
Reduced EPO due to reduced renal mass, reduced RBC lifespan due to uraemia, chronic GI haemorrhage due to ulceration
Which endocrine hormones enhance EPO’s effects?
Thyroid hormone and cortisol
Which endocrine diseases can cause anaemia?
Hypothyroid, Addisons
Which three nutritional deficiencies can cause non-regenerative anaemia?
Iron, copper, B12/folate
What are the two types of erythrocytosis?
Relative or absolute
In which cases is iron deficiency anaemia caused by dietary deficiency?
Fleas or piglets, but not usually dietary deficiency other than this
What kind of anaemia does iron deficiency result in?
Microcytic or hypochromic
Which toxin is associated with methaemoglobinaemia in cats?
Paracetamol
What does blood look like in methaemoglobinaemia?
Chocolate brown
How do you test for methaemoglobinaemia?
Drops venous blood onto blotting paper, stays brown
What kind of haemolysis occurs when eccentrocytes are removed by the spleen?
Extravascular
What toxin is assocaited with methaeoglobinaemia in ruminants and pigs?
Nitrite
Which are the most relevant blood groups in horses?
Aa, Ac, Ca, Qa
Horses lacking which blood antigen may have natural antibodies?
Aa, Ac, Ca
How can Qa -ve mares get anti-Qa antibodies?
After having a +ve foal
Can negative horses have natural alloantibodies?
Yes
When do you get neonatal isoeryhtrolysis in horses?
Aa/Qa -ve mare gets alloantibodies during foaling or transfusion. Then next foal gets autoantibodies from mother causing haemolysis
How do you treat primary erythrocytosis?
Phlebotomise to reduce PCV and viscosity and do chemo
How do you treat secondary absolute erythrocytosis?
Treat cause, then phlebotomise to reduce PCV and viscosity
Which cells are not seen in relative erythrocytosis?
No polychromasia/reticulocytes
What are two causes of relative erythrocytosis?
Dehydration (PP also increased) or splenic contration (PP normal)
Which cells are seen in absolute erythrocytosis?
polychromasia/reticulocytes
What causes primary erythrocytosis?
Neoplastic proliferation of red cells and sometimes other cell lines
Which hormone is secondary erythrocytosis caused by?
EPO
What’s an example of appropriate secondary erythrocytosis?
Hypoxia in CPD or cardiovascular shunting
What’s an example of inappropriate secondary erythrocytosis?
EPO secreted from renal tumour
What are some conditions caused by absolute erythrocytosis?
Epistaxis, congested retinal vessels, seizures
Why do you get poor perfusion in absolute erythrocytosis?
Increased blood volume, sludging of blood, distended blood vessels