Anaemia

Question 1

What is anaemia?

Answer 1

Reduction in RBC mass
-associated with pallor

Question 2

What are the causes on anaemia?

Answer 2

*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)

Question 3

What are the clinical signs on anaemia?

Answer 3

 Pallor
 Weakness
 Exercise intolerance
 Tachycardia
 Tachypnoea
 ‘Haemic’ murmur

Question 4

How would you classify mild anaemia in dogs/cats?

Answer 4

30-36% in dogs, 20-24% in cats

Question 5

How would you classify moderate anaemia in dogs/cats?

Answer 5

• 18-29% in dogs, 15-19% in cats

Question 6

How would you classify severe anaemia in dogs/cats?

Answer 6

*<18% in dogs, <15% in cats

Question 7

What are the signs on regeneration?

Answer 7

• Reticulocytosis and polychromasia are the hallmarks of regeneration

Question 8

What are the main causes of regenerative anaemia?

Answer 8

–Haemorrhage
–Haemolysis

Question 9

What does acute haemorrhage result in?

Answer 9

Hypovolaemic shock
loss of more than 30% of blood = fatal

Question 10

What can chronic blood loss lead to?

Answer 10

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

Question 11

What are the effects of iron deficiency on RBC’s

Answer 11

RBC’s get smaller and hypochromic
(microcytic + hypochromic)

Question 12

Causes of chronic bleeding?

Answer 12

– 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))

Question 13

Treatment of iron deficiency anaemia?

Answer 13

• Iron supplementation
  –Oral ferrous sulphate (preferred)
  –Intramuscular iron dextran (caution!)
• Blood/packed red cell transfusion

Question 14

Causes of haemolysis?

Answer 14

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)

Question 15

How would you diagnose IMHA?

Answer 15

–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

Question 16

Treatment of IMHA?

Answer 16

*Immunosuppressive therapy
*Antithrombotic therapy
*Supportive therapy
Treat underlying disease if secondary

Question 17

What drugs can be use for immunosuppressive therapy?

Answer 17

*Prednisone/prednisolone
*Dexamethasone
*Azathioprine
*Ciclosporin
*Mycofenolate mofetil
*Leflunomide

Question 18

What are the side effects of corticosteroids?

Answer 18

• Polyuria/polydipsia/polyphagia
• Muscle wastage and poor exercise
  tolerance
• GI signs
  – gastritis, ulceration
  – pancreatitis

Question 19

What can be used for antithrombotic therapy?

Answer 19

*Antiplatelet drug (primary haemostasis)
-Clopidogrel
*Anticoagulant (secondary haemostasis)
- Unfractionate Heparin

Question 20

What are the other supportive therapy?

Answer 20

• Blood transfusion
• Gastroprotectants - omeprazole

Question 21

What is Neonatal isoerythrolysis?

Answer 21

Distruction of neonate RBC by maternal antibodies
- v rare in puppies
- rare in kittens

Question 22

What is Microangiopathic Haemolytic Anaemia?

Answer 22

RBCs are mechanically damaged or
fragmented as they pass through fibrin
meshworks in the microvasculature

Question 23

What are Schistocytes?

Answer 23

Fragmented RBC’s

Question 24

What causes oxidative damage in Dogs and cats?

Answer 24

*Onions and zinc toxicity in dogs
*paracetamol in cats

Question 25

What does oxidative injury cause?

Answer 25

– methaemoglobinaemia
– Heinz body formation
– RBC membrane oxidation (eccentrocytes)

Question 26

What is the treatment of oxidative damage?

Answer 26

– immediate withdrawal of the offending cause
– supportive care
– (for methaemoglobinaemia)
* methylene blue
* 1mg/kg once i.v.
– N‐acetyl cysteine for paracetamol poisoning

Question 27

How would you identify non-regenerative anaemia?

Answer 27

• Absence of reticulocytes

Question 28

What are the causes of non-regenerative anaemia?

Answer 28

– Primary marrow disease
– Other diseases affecting marrow function
– Lack of erythropoietin (e.g. due to kidney disease)

Question 29

What drugs can cause marrow disease and therefore non-regenerative anaemia?

Answer 29

– oestrogen (dogs)
– antibiotics
– NSAIDs
– anticonvulsants (phenobarbital)
– antivirals (cats)
– antifungals (griseofulvin in cats)
– methimazole (antithyroid drug used in cats)

Question 30

What does oestrogen toxicity cause?

Answer 30

– thrombocytopenia
– neutrophilia then neutropenia
– anaemia
=non-regenerative anaemia

Question 31

What does anaemia of Chronic Kidney disease cause?

Answer 31

• Normocytic, normochromic, non‐regenerative
  anaemia
• Reduced erythropoietin production
• reduced red cell survival
• reduced erythropoieisis
• haemorrhage
  – thrombocytopathies
  – GI ulceration