How Anemia Affects Dogs
Within red blood cells is a protein called “hemoglobin,” which functions to transport molecular oxygen in the blood to all body tissues. Normally, as red blood cells age or are damaged, they are broken down by other cells, called “macrophages.” Part of the hemoglobin molecule is recycled to the bone marrow to be incorporated into new red blood cells (also called erythrocytes or RBCs). Other parts of the old or damaged RBCs are processed and excreted by the liver. When dogs have an abnormally low red blood cell mass – and therefore an abnormally low amount of hemoglobin available to carry oxygen throughout their bodies – they basically experience varying degrees of oxygen starvation. The consequences of anemia can be mild or life-threatening, depending on its cause and the ability of the dog’s body to regenerate and maintain a healthy red blood cell level.
Owners may notice similar or slightly different signs of anemia depending on whether it comes on suddenly (acute anemia) or slowly (chronic anemia). Dogs suffering from anemia may have one or more of the following symptoms:
- Exercise Intolerance
- Lack of appetite
- Bloody stools
- Abdominal distention
- Pale mucous membranes (pallor); possible mucosal bleeding (primarily of the gums and nasal membranes)
- Difficulty breathing (tachypnea); rapid shallow breathing; respiratory distress
- Elevated heart rate (tachycardia)
- Bounding pulses
- Heart murmur
Most of these signs are non-specific for anemia. However, when a number of them are present in one animal, anemia should be high on the list of suspects.
Dogs At Increased Risk
Dogs of all breeds, any age and either gender can be affected by anemia. Those with heavy parasite loads and with gastrointestinal ulcers are at increased risk of blood loss anemia. Hemolytic anemia (destruction of RBCs) due to varied hereditary defects are seen more so in certain breeds, including English Springer Spaniels and less commonly Cocker Spaniels (phosphofructokinase [PFK] deficiency), and in Basenjis, Beagles, West Highland White Terriers, Cairn Terriers, Miniature Poodles, Toy Eskimos and Dachshunds (pyruvate kinase [PK] deficiency). Greyhounds and Pit Bull Terriers appear to be predisposed to anemia caused by infectious agents.