What is hemolytic anemia?

Hemolytic anemia is a type of regenerative anemia affecting dogs. A dog with haemolytic anemia will suffer from abnormal red blood cell destruction. Hemolytic anemia can be a primary disease or a result of other diseases, such as cancer and various infections. Hemolytic anemia can also be seen in some dogs as a result of vaccination, medication, or exposure to lead. The most important type of hemolytic anemia in dogs is the immune-mediated hemolytic anemia.

What is Autoimmune hemolytic anemia (AIHA)?

An autoimmune disease is the result of the dog’s own immune system turning against the body. The term ‘hemolytic’ is used for diseases that destroy the red blood cells. As a result of the red blood cell destruction, the dog will develop anemia.

In a dog suffering from autoimmune hemolytic anemia (AIHA), antibodies will stick to the red blood cells. This will cause the dog’s immune system to believe that the red blood cells are dangerous invaders, and it will destroy the red blood cells just like they would destroy a virus. The exact reason behind this error varies depending on the cause of AIHA, but it is often the result of a drug, toxin or parasite sticking to the surface of the red blood cells. 

Symptoms of Autoimmune hemolytic anemia (AIHA) in dogs

The lack of oxygen in the blood causes weakness, lethargy and an increased heart rate in dogs suffering from AIHA. The dog will also breathe faster. The mucous membranes of the gums, ears and eyelids can turn pale. A build up of bilirubin can cause yellow colouring of the white parts of the eyes. Other symptoms of autoimmune hemolytic anemia (AIHA) in dogs are vomiting, abdominal pain, blood in urine and/or stool, and fever.

Autoimmune hemolytic anemia (AIHA) medication for dogs

Since autoimmune hemolytic anemia can be caused by a wide range of reasons, the veterinarian will have to determine the original cause of the problem as well as treat the acute symptoms of anemia in the dog. Several different treatments are available for dogs with autoimmune hemolytic anemia and the treatment must be tailor made to fit your dog, the cause of the disease and the overall health status of the dog.

Prednisone medication is one of the most important treatments for autoimmune hemolytic anemia in dogs. Prednisone is a corticosteroid capable of suppressing the dog’s immune system. As the immune system becomes weaker, it will not be able to destroy as many red blood cells as before. The problem is of course that is dog with a weak immune system is susceptible for a wide range of other diseases. The veterinarian will normally give a dog with AIHA very high doses of Prednisone to begin with, in order to put a quick halt to the destruction of red blood cells. A normal dose during the initial stage is 1 mg of prednisone per pound of body weight each day, divided into two doses. In some cases, even higher doses will be necessary. You can expect your dog to show improvement within 5-7 days. The Prednisone dose can then be gradually lowered over the course of many months. examethasone is another corticosteroid drug that can be used in dogs with AIHA. This drug is 5-7 times more potent than Prednisone.

Cytotoxic drugs can be combined with corticosteroids. Some veterinarians will start giving them to the dog from day one, while others prefer to give corticosteroids only for 7 days before introducing cytotoxic drugs.

Danazol is another drug commonly combined with corticosteroids to treat dogs with autoimmune hemolytic anemia. In some dogs, giving Danazol only will be enough once remission has been achieved.

In cases where the abovementioned treatment is not efficient enough, it can be necessary to add even stronger immunosuppressive medication. The veterinarian can for instance prescribed a drug containing Azathioprine, such as Imuran. Your dog might have to be given this drug for up to 6 weeks before you can notice any difference.

Drugs with Cyclophosphamide, e.g. Cytoxan, can be used to treat dogs where the autoimmune hemolytic anemia has lead to severe hemolysis and agglutination. Cyclophosphamide is normally administered daily for 4 days, followed by 3 days without Cyclophosphamide, and then 4 more days with Cyclophosphamide, and so on. Cyclosporine is commonly used to make organ transplantations possible, but its powerful immunosuppressant capacity can also be used to treat dogs with autoimmune hemolytic anemia. The therapeutic range for cyclosporine starts at 300-500 ng/ml (nanogram/milliliter). Cyclosporine is available under several different brand names, such as Atopica, Gengraf, and Neoral.

Other possible Autoimmune hemolytic anemia treatments for dogs

A blood transfusion can be given in life threatening situations. Introducing blood from another dog (e.g. introducing foreign protein) is dangerous for dogs with AIHA and should only be done when absolutely necessary. Artificial blood, such as Oxyglobin, can also be used.

A splectonomy (removal of the spleen) can help dogs with autoimmune hemolytic anemia. It is normally only performed on dogs that have not responded to other forms of treatment.

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