Approach to anaemia 2 Flashcards
What are the 3 main methods of treatment for IMHA?
Treat underlying disease
Immunosuppression (in some cases)
Supportive therapy
Is immunotherapy required for primary or secondary IMHA?
Primary
Sometimes secondary
Should the dose of immunosuppression be high or low for treating IMHA?
Start high and gradually reduce
2 weeks between each reduction
(May be taking for months, or up to life)
What supportive therapies may be given for IMHA?
Oxygen
Fluids
Drugs that reduce platelet activation and the coagulation cascade
Blood transfusion
Does oxygen have much benefit as a supportive treatment for IMHA? Why?
No - requires RBCs to carry the oxygen
May help if pulmonary thromboembolism
Why is fluid therapy an important aspect of IMHA supportive treatment?
Maintains renal and hepatic perfusion
Especially important if intravascular haemolysis
What should you be careful with when using IVFT for supportive IMHA treatment?
Careful not to overload volume
Patients aren’t usually hypovolaemic - just aiming to dilute the haem in blood
What is a serious complication of IMHA? (think due to agglutination)
Thromboembolisms
How can the risk of thromboembolisms (with IMHA) be reduced?
Aspirin and clopidogrel - reduce platelet activation
Heparin and low molecular weight heparin - reduce XS coagulation cascade
Why are blood transfusions controversial for treating IMHA?
May cause even more increased RBC destruction
Risk of pulmonary thromboembolism
Transfused RBCs have short lifespan
Give examples of drugs that may be used to treat idiopathic/primary IMHA
Corticosteroids - prednisolone, dexmethasone
Cytotoxics - azathioprine (dogs), mycophenolate mofetil (cats)
Cyclosporin
When might corticosteroids (prednisolone, dexamethasone) be used to treat IMHA? What are side effects?
Emergencies
Anorexic patients
PUPD, GI signs, long term use damage organs
Azathioprine is a cytotoxic drug that is the drug of choice to treat IMHA in dogs. Would you use it alone? What are the side effects?
Delayed onset of action -use in combination with prednisolone
Myelodepression, GI effects
Azathioprine is a cytotoxic drug that is the drug of choice to treat IMHA in dogs. Can it be used in cats? What should be given?
Not suitable for cats
Use mycophenolate mofetil
What surgical treatment may be considered for treating idiopathic/primary IMHA?
Splenectomy
Make sure not infected with vector borne diseases - worsens condition
What is neonatal isoerythrolysis?
Specific type of IMHA
Neonatal RBCs destroyed by maternal antibodies
Neonatal isoerythrolysis is rare in puppies and kittens. What can cause it?
If mother has different blood type to puppies
Maternal antibodies destroy neonatal RBCs
Neonatal isoerythrolysis can occur in kittens with what blood type? What is the mothers blood type?
Type A or AB kittens
Born to a B queen
What breed of cat is prone to neonatal isoerythrolysis?
British shorthair
Can you give a cat any blood type?
NO
Never give a type B cat type A blood
How can the risk of neonatal isoerythrolysis be reduced?
Avoid mating B queens with A/AB toms
Foster kittens for first 24 hrs - give milk from queen with same blood type
Mycoplasmosis causes what type of anaemia?
Regenerative anaemia (non-regenerative if associated with FeLV/FIV) Due to haemolysis (mostly IMHA)
What organism causes mycoplasmosis in cats
Mycoplasma haemofelis
How can mycoplasmosis in cats be diagnosed?
PCR
Can a cat be treated for mycoplasmosis?
Treatment with doxycycline or prednisolone BUT
Once infected infected for life
What is microangiopathic haemolytic anaemia?
Type of anaemia caused by mechanical damage to RBCs
Microangiopathic haemolytic anaemia is due to mechanical damage of RBCs. What may cause this?
Altered vasculature e.g. haemangiosarcoma
Fibrin nets (DIC)
Glomerulonephritis
Vascular anomalies/congenital heart defects
What RBC abnormalities are found with microangiopathic haemolytic?
Shistocytes
Acanthocytes
What is intrinsic haemolytic anaemia?
Rare inherited metabolic defects
Leads to RBC membrane instability and defects
What are shistocytes?
Fragments of RBCs
What conditions are associated with shistocytes?
Microangiopathic haemolytic anaemia and their causes DIC Glomerulonephritis Neoplasia Vascular anomalies/congenital defects
What are acanthocytes?
RBCs with unevenly spaced projections (vary in length)
What conditions are associated with acanthocytes?
Microangiopathic haemolytic aanaemia Liver disease Lymphoma Spleen disorders High cholesterol diets and cholesterol metabolism abnormalities
Which RBC abnormality can be associated with cholesterol metabolism and high cholesterol diets?
Acanthocytes
What are Heinz bodies? What are they aggregates of?
Round, pale inclusion on surface of RBC membrane
Denatured haemoglobin
What causes Heinz body anaemia?
Oxidative damage (Extravascular or intravascular haemolysis)
What stain highlights Heinz bodies?
New Methylene blue
What can oxidative injury result in (in terms of haematology)?
Non immediate cell destruction:
Methaemoglobinaemia
Heinz body formation
RBC membrane oxidation - fragile membrane - phagocytose by macrophages
Oxidative injury causes non-immune mediated RBC destruction. What is the treatment for this?
Remove what is causing the oxidation
Supportive care
How can non-regenerative anaemia be distinguished from regenerative anaemia on a blood smear?
Non-Regenerative anaemia has absence of reticulocytes
What are some examples of non-regenerative anaemia?
Primary bone marrow disease
Lack of erythropoietin (due to kidney disease)
Other diseases affecting bone marrow function
Intramarrow disease causes a type of non-regenerative anaemia. How is it diagnosed?
Bone marrow sample
Intramarrow disease has many causes. Give some examples of these
Idiosyncratic drug reactions (many drugs) Oetrogen toxicity Pure red cell aplasia Aplastic anaemia Myelofibrosis Myelodisplastic syndromes
Intramarrow disease can be due to oestrogen toxicity. Give examples of what can cause oestrogen toxicity
Exogenous oestrogen (drugs) Endogenous oestrogen e.g. Sertoli cell tumours
What are the symptoms/clinical findings of oestrogen toxicity?
Tumours Intramarrow disease Pancytopenia Thrombocytopenia Neutrophilia then neutropenia Anaemia
How is oestrogen toxicity treated?
Antibiotics
Transfusions
Remove neoplasms
What is the prognosis for oestrogen toxicity?
Very poor - majority die
Intra marrow disease can be due to pure red cell aplasia. What is this and what is likely to cause it?
No erythroid precursors in the bone marrow
Immune mediated
What is the treatment for pure red cell aplasia?
Remove cause
Transfusions
Immunosuppressive therapy
Intra marrow disease can be due to aplastic anaemia. Which cells are affected? what is the treatment?
All blood cells affected
Supportive
Intramarrow disease can be due to myelofibrosis. What is myelofibrosis?
Proliferation of collagen and reticulin fibres in the bone marrow
What causes myelofibrosis - is it primary or secondary?
Secondary to damage of marrow stroma, retroviral infections, can be idiopathic
What is the treatment for myelofibrosis?
Transfusion
Immunosuppression
Anabolic steroids
Anaemia of chronic disease is a common disease AKA anaemia of chronic inflammation. What type of anaemia does this cause?
Normocytic Normochromic Non-regenerative anaemia Usually mild (No specific therapy - resolve underlying disease)
Anaemia of chronic disease causes normocytic, normochromic, non-regenerative anaemia. What causes this disease?
Decreased erythropoietin production
Leads to reduced RBC survival, reduced erythropoiesis and haemorrhage
What is the treatment for anaemia of chronic kidney disease?
Increased erythropoietin concentration
Minimise blood loss
Give examples of 2 feline retroviruses that can cause anaemia
FeLV
FIV
What type of anaemia do FeLV and FIV usually cause - regenerative or not?
Non-regenerative anaemia
FeLV can occasionally cause macrocytic anaemia. What are some of the mechanisms in which FeLV can cause anaemia?
Red cell aplasia Aplastic anaemia Anaemia of chronic disease Myelodysplasia Acute leukaemia
FIV causes non-regenerative anaemia. Which blood cells are usually more affected?
Granulocytes
Eosinophil, basophil, neutrophil
