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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Anaemia is a reduction in the number of red blood cells in the blood and in oxygen carrying capacity of the blood

Anaemia can be diagnosed based on clinical signs, for example :

  • the animal will have pale mucous membranes, eg gums, lips
  • fatigue
  • increased respiratory rate
  • increased heart rates

It is confirmed on laboratory examination of blood samples.

There are many possible causes of anaemia - which may require other tests to be performed to make the diagnosis, including the following :

  • Haemorrhagic anaemia - blood loss from the body - the most common cause of anaemia in pets
    • External haemorrhage - wounds, nose bleeds
    • Internal haemorrhage - into urine, faeces or body cavities eg the abdomen
    • Common causes of haemorrhage include :
      • Trauma
      • Tumours of various organs
      • Blood clotting defects
      • Poisoning with anticoagulants eg warfarin - prevent blood clotting and cause haemorrhages
      • Severe liver disease - the liver manufactures important clotting factors
      • Large numbers of blood-sucking parasites eg ticks, hookworms
      • Gastrointestinal ulcers - can occur after drugs eg non-steroidal anti-inflammatory drugs (NSAIDs) 
  • Haemolytic anaemia - increased destruction of red blood cells - the least common cause of anaemia in pets
    • Autoimmune disease - caused by antibodies being produced against the animals own red blood cells
    • Toxins - eg snake venom, onions, paracetamol, phenylbutazone, fertilizers (nitrates), lead, copper
    • Blood parasites - eg Mycoplasma haemofelis (previously called feline haemobartonella infection), leptospirosis, canine heartworm (dirofilaria immitis)
    • Reaction to an incompatible blood transfusion
    • Hypotonic fluids given intravenously
    • Physical injury to red cells - burns, radiation poisoning
    • Low blood phosphorus (hypophosphataemia)
    • Some malignant cancers eg haemangiosarcomas
  • Inadequate production of red blood cells
    • Nutritional deficiencies (rare) - iron, protein, Vitamin B (folate, niacin, pyridoxine, riboflavin)
    • Bone marrow disease
      • Secondary to other diseases eg inflammation, cancer, renal failure, liver disease, infections
      • Toxicity - drugs, heavy metals

Some forms of anaemia are treatable but others are not. Treatment includes :

  • Stop blood loss
  • Treat the underlying (primary) disease
  • Blood transfusions
  • Ensure adequate nutritional intake
  • Avoid contact with toxins
  • Drugs that influence the immune response

Last updated : March 2013