Anemia - Part 2

Pet Tales
by Barry B. Burtis D.V.M.

Anemia is a blood disorder that is frequently encountered in their patients by veterinarians in small animal practice. It can be a very serious, possibly life threatening condition in cats and dogs who become affected by it. To determine the cause of an anemia, can be quite a diagnostic challenge. Treatment may be difficult. Certainly it's not just a matter of prescribing a multi-vitamin mineral supplement for "tired blood", as television ads once portrayed anemia.

When their story ended in my last column both Tyson, a middle aged neutered male cat and Lady, a just senior (8 years old) spayed female cocker spaniel had been diagnosed with anemia. The symptoms noticed in each pet, by their respective owners, were very similar and were primarily caused by the anemia and their resultant inability to get oxygen to the tissues in the body where it is needed for normal metabolism. Lady and Tyson were lethargic, depressed and had recently lost interest in eating. They were very weak and non-responsive to normal stimuli. Both patients were admitted to the hospital for nursing care and supportive treatment when their illness struck.

At the same time that symptomatic treatment is initiated, other diagnostic measures are continued, attempting to determine the cause of the anemia. There are a variety of other tests that may need to be considered but almost always more blood tests are the most likely to be helpful. One very important thing to find out is whether the anemia is regenerative or non-regenerative. In other words, is the body responding appropriately to the problem by producing new, immature red blood cells or is it not. Examination of blood smears from the patient, spread out on a glass microscope slide, and using a microscope to count the immature red cells will yield this information.

Most red blood cells are produced in the bone marrow, the central cavernous area in certain large, long bones in the body. A regenerative anemia is usually associated with blood loss from the circulation or destruction of red blood cells after they are produced (i.e. extra marrow causes). A non-regenerative anemia is characterized by lack of bone marrow regeneration and can be due to primary bone marrow or extra-marrow disorders.
Lady and Tyson both had a regenerative anemia.

Examination of Tyson's blood smear provided even more valuable information in determining the cause of his illness. Haemobartonella felis a mycoplasma or bacteria-like parasite was detected on certain of his red blood cells in the blood smear. When the parasite attaches to the outside surface of the red blood cell, a cat's immune system recognizes it as different and destroys the red blood cell, eventually leading to anemia. Without treatment, mortality may reach 30% in cats. Treatment with doxycycline or tetracycline antibiotics for 3 weeks is usually very successful in treating the infection. Tyson's packed cell volume was rechecked a week after treatment was started and was found to be quickly returning to normal levels. Tyson will likely remain a carrier of the disease after treatment but once he is no longer anemic he is unlikely to relapse.

It turns out that Lady's malfunctioning immune system was also causing her illness. Lady was found to have immune-mediated hemolytic anemia. This disease most frequently affects female dogs of the following breeds; Old English sheepdogs, cocker spaniels, poodles, Irish setters, English springer spaniels and collies. The diagnosis took a bit longer to reach and, as in most cases of this disease in dogs, it was never determined exactly what triggered her immune system to begin destroying apparently normal red blood cells. Treatment efforts are directed at stabilizing the acute medical crisis and using powerful drugs to try and suppress the immune system that is malfunctioning. Depending whether or not such things as thromboembolism, heart beat irregularities and clotting disorders complicate the initial stages of the disease, mortality rates can reach  30-80%. Lady responded successfully initially to treatment efforts.

However, sadly, three months after the initial episode and while still on medications to try to control the disease, Lady had a relapse. This, unfortunately, is known sometimes to happen. Concerned with Lady being so seriously ill again and faced with such an unknown future for such a dearly loved pet, Lady's owners chose to let her life end peacefully and with dignity and she was euthanized.