Anaemia Flashcards
What is anaemia?
Reduction in RBC mass
-associated with pallor
What are the causes on anaemia?
*1 Inadequate production by the bone marrow
–Non-regenerative
–Typically normocytic normochromic
*2 Increased destruction
–Regenerative (exceptions)
–Typically macrocytic hypochromic
*3 Loss (haemorrhage)
–Not regenerative enough
–Typically microcytic, hypochromic
–(Hypoproteinaemia)
What are the clinical signs on anaemia?
Pallor
Weakness
Exercise intolerance
Tachycardia
Tachypnoea
‘Haemic’ murmur
How would you classify mild anaemia in dogs/cats?
30-36% in dogs, 20-24% in cats
How would you classify moderate anaemia in dogs/cats?
- 18-29% in dogs, 15-19% in cats
How would you classify severe anaemia in dogs/cats?
*<18% in dogs, <15% in cats
What are the signs on regeneration?
- Reticulocytosis and polychromasia are the hallmarks of regeneration
What are the main causes of regenerative anaemia?
–Haemorrhage
–Haemolysis
What does acute haemorrhage result in?
Hypovolaemic shock
loss of more than 30% of blood = fatal
What can chronic blood loss lead to?
bleeding for >2 weeks
* May lead to consumption of iron stores and
iron deficiency anaemia (IDA)
* Initially regenerative, becoming less or non-
regenerative due to depletion of iron
What are the effects of iron deficiency on RBC’s
RBC’s get smaller and hypochromic
(microcytic + hypochromic)
Causes of chronic bleeding?
– Typically from GI tract
* NSAIDs, steroids, neoplasia, ulcers, CRF
– Can also result from haemorrhage from other systems
– Urinary tract
– Skin
– Respiratory tract
– (Congenital haemostatic defects)
– (Parasitic infestations (external/internal))
Treatment of iron deficiency anaemia?
- Iron supplementation
–Oral ferrous sulphate (preferred)
–Intramuscular iron dextran (caution!) - Blood/packed red cell transfusion
Causes of haemolysis?
Immune-mediated
* immune-mediated haemolytic anaemia
*primary
*secondary to infection or neoplasi)
*neonatal isoerythrolysis
Non immune-mediated
* oxidative damage: onions, paracetamol in cats,
zinc,
*intra-erythrocytic parasites
*mechanical damage (angiopathic anaemia)
How would you diagnose IMHA?
–Typically regenerative anaemia (exceptions)
–Autoagglutination (not always present)
–Spherocytes (especially if many)
–Leukocytosis with left shift
* Direct antiglobulin test (Coombs’ test or other)
–Demonstration of anti-RBC antibodies
Treatment of IMHA?
*Immunosuppressive therapy
*Antithrombotic therapy
*Supportive therapy
Treat underlying disease if secondary
What drugs can be use for immunosuppressive therapy?
*Prednisone/prednisolone
*Dexamethasone
*Azathioprine
*Ciclosporin
*Mycofenolate mofetil
*Leflunomide
What are the side effects of corticosteroids?
- Polyuria/polydipsia/polyphagia
- Muscle wastage and poor exercise
tolerance - GI signs
– gastritis, ulceration
– pancreatitis
What can be used for antithrombotic therapy?
*Antiplatelet drug (primary haemostasis)
-Clopidogrel
*Anticoagulant (secondary haemostasis)
- Unfractionate Heparin
What are the other supportive therapy?
- Blood transfusion
- Gastroprotectants - omeprazole
What is Neonatal isoerythrolysis?
Distruction of neonate RBC by maternal antibodies
- v rare in puppies
- rare in kittens
What is Microangiopathic Haemolytic Anaemia?
RBCs are mechanically damaged or
fragmented as they pass through fibrin
meshworks in the microvasculature
What are Schistocytes?
Fragmented RBC’s
What causes oxidative damage in Dogs and cats?
*Onions and zinc toxicity in dogs
*paracetamol in cats
What does oxidative injury cause?
– methaemoglobinaemia
– Heinz body formation
– RBC membrane oxidation (eccentrocytes)
What is the treatment of oxidative damage?
– immediate withdrawal of the offending cause
– supportive care
– (for methaemoglobinaemia)
* methylene blue
* 1mg/kg once i.v.
– N‐acetyl cysteine for paracetamol poisoning
How would you identify non-regenerative anaemia?
- Absence of reticulocytes
What are the causes of non-regenerative anaemia?
– Primary marrow disease
– Other diseases affecting marrow function
– Lack of erythropoietin (e.g. due to kidney disease)
What drugs can cause marrow disease and therefore non-regenerative anaemia?
– oestrogen (dogs)
– antibiotics
– NSAIDs
– anticonvulsants (phenobarbital)
– antivirals (cats)
– antifungals (griseofulvin in cats)
– methimazole (antithyroid drug used in cats)
What does oestrogen toxicity cause?
– thrombocytopenia
– neutrophilia then neutropenia
– anaemia
=non-regenerative anaemia
What does anaemia of Chronic Kidney disease cause?
- Normocytic, normochromic, non‐regenerative
anaemia - Reduced erythropoietin production
- reduced red cell survival
- reduced erythropoieisis
- haemorrhage
– thrombocytopathies
– GI ulceration
