Auto Immune Haemolytic Anaemia (AIHA)


Auto Immune Haemolytic Anaemia (AIHA) is a condition in which the body’s defences, the immune system, suddenly identify the red cells in the circulation as a foreign body, and destroy them. This can be caused by a fault in the immune system itself, and is called primary (or sometimes idiopathic) AIHA or it can be caused by the red cells being altered by chemical action or another disease process. This AIHA is called secondary. The results are the same, with red cells being broken down and releasing their haemoglobin into the bloodstream. This has various effects, mainly anaemia and all the problems that brings with it, such as racing heart and shortness of breath because the blood can’t carry oxygen, but also the liver can be damaged as it tries to remove the debris of a broken red cell and the haemoglobin from the circulation.

Symptoms of AIHA

The main symptom of AIHA is pallor of the mucous membranes, showing that the cat is anaemic. The anaemia can come on quite slowly, so you may not notice immediately that your cat is unwell, because it will gradually become more tired and lethargic in the first instance. Obviously when the anaemia becomes more profound, your cat will show symptoms such as racing heart and breathlessness as the body tries desperately to get enough oxygen to the tissues. Haemoglobin can only carry oxygen when it is in a red cell, so it is useless when the cell is broken (lysed). Eventually, the cat will start to show symptoms of liver damage as well, which will be anorexia and dark urine. It will be jaundiced, but in some cats this is difficult to see. If your cat is light coloured, you may be able to see it in the skin of its ears, or sometimes in the very corners of its eyes.

Can I diagnose and treat AIHA myself?

Only the vet can treat auto immune haemolytic anaemia and diagnosis can be quite tricky. It is also important to discover whether or not it is idiopathic or secondary, because this has an impact on the treatment. A blood test will certainly be required, and a total red cell count and the haematocrit are the most important figures as they will tell the vet how many unbroken red cells are in circulation. If anaemia is diagnosed, other tests will be done to see if it is caused by haemolysis of cells or because the bone marrow is not working properly. If haemolysis is diagnosed, then more tests will be needed to see if it is primary or not.

The blood is tested for conditions which change the red cells, such as feline leukaemia or haemobartonellosis. If they are present, then that will almost certainly be the cause of the haemolysis (secondary) and the vet will treat whichever disease is found to be present. This will involve antibiotics or antivirals in the first instance, although a transfusion may also be ordered, if the anaemia is very serious. This is also part of the treatment for haemobartonellosis, so this will help if this is the cause. If there is no obvious secondary cause, the diagnosis of primary AIHA can quite confidently be made, but there are various other blood tests to confirm it, which the vet will order to be done. Many vets take enough blood for the lab to add tests as necessary and this is good as the last thing the cat needs at this stage is the stress of constant needles.

Treatment of Auto Immune Haemolytic Anaemia

If the AIHA is found to be secondary, the first port of call is to remove the cause. If it is another disease it must be treated. If it is an outside agent, such as a toxin or possibly a sting or a drug reaction, this must be removed or dealt with. Once this is done, the cat will respond quickly to treatment to improve the anaemia and as long as the secondary cause does not recur, there should be no relapse into AIHA. If it is idiopathic, though, the treatment is rather more lengthy and may not be totally successful. It is at best a holding strategy, using immunosuppressants to stop the red cells from being destroyed.

The right balance of drugs will vary from cat to cat, as many of the medications used in this situation can be quite difficult for the animal to tolerate and as soon as there is an improvement in condition the vet will probably lower the dose. The cat will need to be monitored, though, because the drugs are not a cure but a treatment and they will need to be given for the rest of the cat’s life, in various doses.

Life expectancy for cats with AIHA

As long as there has been no permanent organ damage, a cat which has suffered from secondary AIHA should survive normally, as long as the cause of the condition is not in itself life threatening. In primary AIHA as long as the drugs are tolerated well, the life expectancy is quite good also. The main thing to remember with any serious condition such as this is that the better the condition of the cat at diagnosis, the better the chances of survival with a reasonable quality of life. Watching your cat for signs of ill health should be a natural part of being a caring owner and any behaviour which is different from normal and which lasts for more than a few days should be dealt with as quickly as possible.


You can now get advice online 24/7 from a qualified vet: Ask a Vet Online Now

Close Bitnami banner