Chronic Anemia in Dogs

It is important to remember that chronic anemia can have various causes and as a result, a thorough physical exam, history taking and a few laboratory tests need to be done in order to diagnose the underlying cause. As such, treatment plans and prognosis may vary depending on the individual case.

Red blood cells are composed of a protein known as hemoglobin. Within this protein are iron atoms; these atoms are able to take up oxygen. And so, red blood cells play an important role in oxygen transport and carbon dioxide excretion. When a dog is diagnosed with chronic anemia this indicates that blood cell count, packed cell volume and hemoglobin concentration may be significantly low.

As chronic anemia is multifactorial and may be caused by a possibility of disease, it is important to realise that the symptoms listed below may not be solely associated with anemia alone. Nevertheless, common symptoms associated with chronic anemia include:

• Lethargy over time
• Inability to exercise for extended periods
• Difficulty breathing
• Collapse
• Abdominal distension
• Heart murmurs may develop
• Pale gums
• Increased breathing 
• Increased heart rate 
• Hypothermia
• Anorexia 

It is important to note that chronic anemia often allows the dog to adjust to the drastic decrease in the oxygen carrying capacity of the blood.

Types 

• Blood loss 
• Hemolysis which refers to as the destruction of blood cells
• Regenerative anemia 
• Non-regenerative anemia 
• Aplastic anemia, which is a decrease in or an inability for the body to produce new blood cells and/or hemoglobin

• Severe gastro-intestinal parasites - Often this can be either chronic or acute; in chronic cases, blood loss due to parasites may gradually lead to iron deficiencies in the dog
• Chronic kidney disease - Kidney failure often involves a decrease in the production of erythropoietin, thus, there are less circulating red blood cells; furthermore, chronic kidney failure leads to a very uremic environment (increased urea) this decreases red blood cell survival
• Iron deficiency - May be caused by chronic blood loss as a result of untreated parasitic infections (for example hookworms), neoplasia, ulceration and/or extensive, untreated ectoparasitism
• Non-immune mediated anemia and immune mediated anemia are examples of hemolytic anemia
• Aplastic anemia resulting from failure of bone marrow to produce red blood cells

Your veterinarian will first conduct a full clinical exam to evaluate the key clinical symptoms present in the dog. They will ask for the history of the animal, and the duration and onset of the clinical signs. A complete blood count will be done along with an examination of the platelet and reticulocyte count. A reticulocyte count examines the turnover time of blood cell regeneration from bone marrow.

Blood smears may be done as well in order to view any abnormalities in blood cell structure.

Your veterinarian may further do a blood chemistry panel and urinalysis. This is done in order to rule out the possibility of metabolic diseases such as kidney failure and diabetes. 

Should the veterinarian suspect hemorrhaging on the gastrointestinal tract,  X-rays may be taken, along with packed cell volume checks and blood smears. In the case of non-regenerative anemia as a result of bone marrow disease, a bone-biopsy may be taken along with DNA-based testing.

As the cause for chronic anemia is quite extensive, your veterinarian’s treatment plan will depend on the underlying, associated disease. However, the common goal of all anemia treatments involves bringing the oxygen carrying capacity to stability. To do this, your veterinarian may administer electrolytes in the form of intravenous fluids to increase blood volume.

Should your veterinarian suspect significant blood loss either due to gastrointestinal tumors, parasites or ulcerations, then an emergency blood transfusion along with fluid therapy will be the method of treatment in order to prevent the animal from going into shock. Treatment for iron deficiency anemia can either involve a transfusion of packed or whole blood cells. When iron levels drop significantly over time, your veterinarian may administer 10 to 20 mg/kg of  iron dextran. After the first injection, oral administration of ferrous sulfate given at 100 to 300 mg/kg per day may be given to maintain and gradually bring up iron levels and the oxygen carrying capacity of blood. Potassium sulfate and Vitamin C may also be part of the treatment plan depending on the individual case and cause.

Recovery is often dependent on what the underlying cause for the chronic anemia was. Once the underlying cause of the chronic anemia has been diagnosed, the aim is to manage any continuing blood loss and electrolyte imbalance and to increase the oxygen carrying capacity.

Most often, chronic anemia may take months to years to resolve depending on its underlying cause. Older dogs that have chronic anemia due to kidney disease or diabetes may never completely recover and may slowly deteriorate over time. Geriatric dogs may often remain on supportive care that may involve regular subcutaneous fluids to restore electrolyte balance or oral iron supplements.

Dogs that develop anemia due to chronic blood loss from parasites may be treated with anthelmintics. Often, the recovery period for dogs suffering from chronic blood loss is good and quick if the cause of blood loss is treated quickly. 

Dogs with anemia due to bone marrow malfunction may take months to recover and still may require further treatment. Your veterinarian may suggest continuing regular oral doses of iron supplements along with 500 to 1000mg of vitamin C.