IMHA - Immune Mediated Hemolytic Anemia
Clotting, or coagulation, takes place when blood transforms from a liquid to a thickened gel-like state. Once in this state, the gelled blood is called a clot. It is through the clotting process that a wound begins to heal. If a dog continues to bleed uncontrollably through a wound, this may be a sign of a clotting disorder. The failure of blood to clot can also result in internal hemorrhaging.
There are several different clotting disorders that can occur in dogs. One common condition is called Immune Mediated Hemolytic Anemia (IMHA). Anemia is a condition that arises when the number of red blood cells falls below normal values, or the red blood cells function improperly. IMHA is a result of a dog’s immune system destroying its own red blood cells (RBC’s). The body is still producing RBC’s, but the immune system is mistaking them as something foreign, like a virus or infection, and destroying them. There are two forms of IMHA: primary and secondary. With primary IMHA, the immune system produces antibodies that attack its own RBC’s. This is the most common cause of anemia in dogs. With secondary IMHA, the surface of the RBC is modified by an underlying disease, drug, or toxin, and the immune system identifies them as foreign and destroys them. Secondary IMHA can be triggered by conditions such as cancer, infections, blood parasites, drug reactions, snake bites, bee stings, exposure to certain chemicals or toxins, and allergic reactions. Symptoms of both types may include pale gums, lethargy, shallow or rapid breathing, faster than normal pulse, lack of appetite, weight loss, black or tarry stools, and eating dirt. These symptoms vary from dog to dog and depend on the underlying cause of IMHA. In mild or early IMHA, a dog may present no signs at all.
When diagnosing IMHA, it is important to identify the underlying cause. Your veterinarian may recommend particular tests depending on the pet’s symptoms and history. These tests may include, but are not limited to:
A complete blood count (CBC) to identify IF the dog is anemic, and if so, whether or not his body is responding to the anemia by producing new RBC’s
A reticulocyte count to help identify if the dog’s body is responding to the anemia by making new RBC’s
A blood film to look for parasites and blood cell characteristics
Blood chemistry tests to evaluate kidney, liver, and pancreatic function
Fecal analysis to evaluate for intestinal parasites
Radiographs and ultrasounds to determine if the IMHA is primary or secondary
Any dog can get IMHA, but the most commonly affected breeds are Irish setters, poodles, English springer spaniels, cocker spaniels, collies, and Doberman pinschers. IMHA cannot be transmitted from one dog to another.
Treatment of IMHA will depend on the severity of the condition. Some dogs need intensive care, while others may be treated as an outpatient. Treatment often includes a variety of drugs and close monitoring of the dog’s vital signs and lab values (CBC’s and blood chemistry panels are the two most common). With secondary IMHA, treatment of the underlying cause is critical. The prognosis of a dog with IMHA is dependent upon the underlying cause, the severity of the disease, the stage at which the disease is diagnosed, and the dog’s overall health and history.