Immune-Mediated Hemolytic Anemia, Canine - contd.
Treatment is directed toward any identified underlying causes of the hemolytic anemia and toward symptomatic illness secondary to the IMHA itself. Emergency treatment of a patient with IMHA frequently requires blood transfusion or the use of synthetic hemoglobin solutions to temporarily stabilize the patient and to permit time for other treatments to work. Packed red blood cells from a universal or cross-matched donor are used if available, but whole blood may also be used. It is possible that transfused red blood cells may also be destroyed by the patient's immune system, so the benefit from transfusion may only be temporary.
Synthetic hemoglobin solutions have the advantage of a longer shelf life compared to blood, so they can be used in hospitals where blood donors are not available. However, their expense and their interference with the ability to monitor some biochemical parameters in patients with IMHA must be kept in mind. Plasma may also be given to patients that are thought to have serious blood clotting abnormalities secondary to their disease.
The main thrust of drug treatment in IMHA is the use of drugs to suppress the immune system. Corticosteroids like prednisone, prednisolone, and dexamethasone are most commonly used to accomplish this goal. High doses are necessary, and therefore side effects are common. Some side effects like increased thirst, increased urination, increased appetite, and panting are not very serious, but others, including the potential for gastrointestinal injury, can be severe. When immunosuppressive doses of steroids are used, most animals are placed on drugs to protect the gastrointestinal tract from ulceration.
Additional drugs to suppress or modify the immune system are commonly used to treat IMHA. It is thought that combination therapy may be more effective in some patients, and that it may limit side effects from over-reliance on a single class of drugs. These drugs have the potential to cause serious side effects, such as liver injury or bone marrow suppression, so patients must be carefully monitored. The medications may be used on a one-time only basis, or for longer periods of time during treatment. Examples of these drugs include azathioprine, cyclophosphamide, and danazol.
Some very expensive medications may also be used in the fight against IMHA. These include human intravenous immunoglobulins, and cyclosporine, a drug commonly used in transplant recipients to prevent organ rejection.
In some IMHA-patients that have failed to adequately respond to medical treatment, surgical removal of the spleen may also be considered. This invasive step is seldom performed, although there are some reports that indicate it can be associated with a high degree of success. Because many patients with IMHA are in such critical condition, the risk of general anesthesia may be too high.
Despite a relatively large number of treatment options and treatment protocols with these medications, there is no one agreed upon, universally effective treatment for IMHA. All possible treatments have potential side effects that need to be carefully monitored, and once an animal is successfully managed through an initial crisis, long-term treatment is usually necessary.
