Dogs are pretty efficient at recycling their red blood cells. But when the process breaks down, anemia -- a drop in red blood cells -- may set in. Hemolyisis occurs when a dog's red blood cells break down faster than they should. If left untreated, hemolysis can lead to organ damage and even death.
Red Blood Cells
Red blood cells, produced in bone marrow, carry oxygen throughout the body. A cell's typical life span is about four months, after which it breaks down and the iron the cell carries is recycled to make fresh cells. Adult dogs typically have 39 percent to 60 percent red blood cells by volume. When that measure dips below 37 percent, anemia sets in. Less oxygen carries through the body, and unrecycled iron builds up the dog's system.
Anemia is not itself a disease, it is a symptom. When a dog becomes anemic, she cannot process oxygen efficiently and will likely become lethargic or easily tired. Hemolysis is an acceleration in the breakdown of red blood cells, causing a surplus of depleted cells and iron that can lead to enlarged lymph nodes, spleen or liver. Signs of hemolysis in dogs include jaundice and darkening of the urine. Your dog may also appear pale and develop a rapid heart rate.
Hemolysis is an autoimmune condition, meaning that a dog's immune system directs its disease-fighting antibodies at the red blood cells. The condition, called immune-mediated hemolytic anemia, is often hereditary, but can result from a reaction to medicine such as acetaminophen, an injury such as a poisonous snake bite, or from an infectious disease. Many infections produce toxins that target red blood cells.
Treatment and Outlook
If you suspect your dog may be anemic, take him to your vet right away. In most cases, corticosteroid and immunosuppressant administration can block the antigen/antibody reaction and thus prevent further breakdown of red cells. Blood transfusions and splenectomy are reserved for severe cases or otherwise when the spleen is shown to contribute to the hemolytic process. The outlook, however, is iffy. Even with appropriate medical treatment, the mortality rate associated with hemolysis is almost 40 percent.