Anemia is not only a common problem in critically ill humans but also in TKand veterinary patients. Defined as an inability to carry adequate oxygen to the tissues of the body, anemia is caused by a decrease in the number of circulating red blood cells or a decrease in the amount of circulating hemoglobin (the red pigment inside red blood cells that actually traps and carries oxygen molecules).
Symptoms of anemia vary depending on how fast the blood was lost and the severity of the deficiency. Severe acute anemia will cause high heart rate, shock, collapse, and even death. These pets may or may not have pale gums. In contrast, chronically anemic patients may be lethargic, weak, or have poor appetites. With time, their gums may become very pale, and they may not be able to exercise. As the heart and lungs try to compensate for the anemia, the body will constrict peripheral blood vessels and increase both the heart rate and respiratory rate.
Pets may become anemic for several reasons, such as destruction of the red blood cells or decreased red-blood-cell production in the bone marrow; these can be triggered by immune mediated diseases, infections, cancers, chronic inflammatory diseases, chronic kidney disease, and some types of toxins. Another way animals become anemic is blood loss, either externally (e.g., a large wound, laceration, or severe bloody nose) or internally, such as bleeding into the abdomen, which is a common cause of acute and life-threatening anemia. Yet another way bleeding can occur is by toxins or drugs, including anticoagulant rat baits; warfarin; heavy metals such as zinc and lead; aspirin and other non-steroidal anti-inflammatory medications; heparin; and chronic exposure to estrogens, onions, or garlic.