Anaemia refers to a decrease in red blood cells in the bloodstream. Red blood cells are produced in the bone marrow and are responsible for carrying oxygen from the lungs to all body tissues and organs. There are lots of different types of anaemia, which may be caused by different conditions – so there’s no one treatment. However, most types are treatable… so read on for more details!

A feline red blood cell’s lifespan is 70 days, which is short compared to approximately 120 days in humans and dogs. Furthermore, cats also have a relatively low blood volume of 60 millilitres per kilogram (ml/Kg) of body weight; compared to 90 ml/Kg in dogs and 75 ml/Kg in humans. For these reasons, cats are prone to developing anaemia; however, this species has developed mechanisms to cope with a low red blood cell count. Therefore, when clinical signs are displayed, anaemia is often already severe.

What are the signs of anaemia?

Without red blood cells, there is less oxygen being transported to the tissues. Therefore, the body slows down, and cats can appear tired, lethargic or listless. Their gum colour can become paler than normal, white or, occasionally, yellow. In an attempt to deliver oxygen quicker, the heart can beat faster resulting in an increased heart rate. 

Different types of anaemia

Anaemia is a manifestation of a disease process and not a specific disease itself. And there are multiple possible causes for a decrease in red blood cells. These causes can be divided into three groups: anaemia due to loss of red blood cells; destruction of red blood cells; or impaired production of red blood cells. Examples of these are discussed below.

After identifying anaemia, your vet will try to determine the type of anaemia, to then reach a diagnosis and establish a treatment plan.

Treatment of anaemia

Because anaemia is a manifestation of an underlying problem, treatment is directed at correcting its cause and there is no “one size fits all”. 

How urgent treatment is largely depends on how quickly the decrease in red blood cells occurred. If there is a rapid decline, for example in an active bleeding secondary to an injury, the body does not have the time to adapt to the lack of oxygen and treatment needs to be established urgently. If the decline was slow, for example with blood in stools over a larger period of time, the body has mechanisms to adapt to this. Therefore, treatment is usually not an emergency.

Regardless of the cause of anaemia, blood transfusions may be indicated in critical cases to buy cats some time while diagnostic tests or correction of the primary problem take place. However, it is just a temporary measure, as it does not correct the underlying problem.

Loss of red blood cells

  • Acute haemorrhage – if there is active bleeding from a mass or as result of trauma, this needs to be controlled, often with surgery, for the anaemia to be corrected successfully.
  • Chronic haemorrhage – if bleeding is mild and has occurred over a long period of time, for example in cases of blood in stools or urine, mouth ulcers or heavy flea infestation, the primary problem (gastrointestinal parasites or ulceration, urinary disease or external parasites) needs to be controlled for the anaemia to be resolved.
  • Clotting problems – there are several causes of clotting disorders which can lead to severe acute blood loss or more chronic blood loss. These need to be addressed and corrected for anaemia to be treated effectively.

Destruction of red blood cells

  • Immune-mediated haemolytic anaemia – cats’ immune system can attack red blood cells as a result of an immune-mediated disease, as a response to drug administration, presence of blood parasites, cancer or exposure to toxins. These need to be identified and corrected for successful treatment of anaemia.
  • Intoxication – exposure to certain toxins, such as onion, garlic, acetaminophen, zinc and anti-freezing can lead to oxidative damage of red blood cells. If this is the case, toxin exposure needs to be identified and appropriate treatment put in place for anaemia to be corrected.

Impaired production of red blood cells 

  • Production of red blood cells can be reduced or completely stopped in cases of bone marrow disease, chronic liver and kidney disease, hypoadrenocorticism, hypothyroidism, iron deficiency and other disease processes. These problems need to be ruled out and managed for anaemia to be corrected.

Take-home notes:

  • Anaemia refers to the lack of circulating red blood cells in the bloodstream.
  • It is a manifestation of a problem and not a disease itself.
  • Signs of anaemia include pallor, tiredness and nausea.
  • Treatment is directed at its cause and, therefore, further investigation is often necessary when anaemia is identified.

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