What is anemia?
Anemia refers to a decrease in the number of circulating red blood cells (RBCs), hemoglobin (Hb or Hgb), or both. It is not a specific disease, but rather the result of some other disease process or condition.
Red blood cells are produced in the bone marrow and released into the bloodstream, where they circulate for about three months. As red blood cells age or become damaged, they are removed from the bloodstream and their components are recycled to form new red blood cells. The number of red blood cells may decrease due to decreased production, lysis (cell destruction), or increased loss as seen in bleeding (hemorrhage).
Hemoglobin delivers oxygen to the body's cells and tissues, and dogs with anemia can show signs associated with hypoxia.
Anemia occurs when the number of red blood cells decreases, which can be measured by red blood cell count or hemoglobin concentration. It can develop from the loss, destruction or lack of production of red blood cells. Anemia is classified as aplastic or non-plastic. In regenerative anemia, the bone marrow responds appropriately to the reduced number of red blood cells by increasing the production of new blood cells. In nonregenerative anemia, the bone marrow does not respond adequately to the increased demand for red blood cells. Anemia caused by bleeding or destruction of existing red blood cells is usually regenerative. Anemia caused by a decrease in hormones that stimulate erythropoiesis or bone marrow abnormalities is nonregenerative.
What are the signs of anemia in dog?
The signs of anemia in dogs depend on the severity, duration and underlying cause of the disease. Sudden anemia can lead to shock or even death if more than one-third of the blood volume is rapidly lost and not replaced. Following rapid blood loss, animals usually develop a rapid heart rate, pale gums, and low blood pressure. The cause of blood loss may be obvious, such as serious injury. If no evidence of external bleeding is found, your veterinarian will look for internal or hidden sources of blood loss, such as ruptured spleen tumors, gastric ulcers, bleeding disorders, or parasites. If red blood cells are destroyed, the animal may develop jaundice (yellow coloration of the whites of the eyes, skin or gums). Animals with chronic anemia have time to adapt, and their signs usually develop more slowly. These include loss of energy, weakness and loss of appetite. Affected animals will have similar physical findings, such as pale gums, increased heart rate, possible enlargement of the spleen or heart murmur.
A complete medical history is an important part of diagnosing anemia. Questions your veterinarian may ask include how long the signs have been present; whether there has been any exposure to toxins such as rodent poisons, heavy metals or toxic plants; what medications and vaccinations the pet has received; where the pet has been; and any prior illnesses.
A complete blood count is another diagnostic tool your veterinarian will use to provide information about the severity of anemia, the degree of bone marrow reaction, and other types of blood cell conditions. Tests should be performed to evaluate red blood cell size and shape and to check for red blood cell parasites.
The most common symptoms of anemia in dog are -
1. Pale gums
The most obvious and directly observable symptom of anemia is a change in the color of your dog's gums!
When a dog's gums become lighter in color, or even pale, it may be the result of anemia or low blood pressure. Normal dog gums are bright red, sometimes if the color is not easy to distinguish, you pooper scoopers can try to press the gums and then release them to see if the time from white to normal is more than 1 second.
2. Loss of appetite
When a dog is sick, loss of appetite is the most common symptom, and anemia is certainly no exception, so if you find that your dog can't even eat his favorite meat in front of him, be sure to take him to the doctor.
3. Shortness of breath
Dogs with anemia will have a reduced ability to transport oxygen in their blood to meet the needs of the dog's body organs and may experience shortness of breath or panting, and when a pooper scooper observes this symptom, it means that the dog's anemia is more severe.
If your dog is showing signs of kidney disease, it is time to get your pet to the vet immediately. In order to get good treatment, it is important to get an accurate diagnosis and start treatment as soon as possible.
Can dogs develop iron deficiency anemia?
Iron deficiency anemia is a condition that is relatively common in people, especially women. Iron deficiency is common in dogs and is usually secondary to some form of chronic blood loss. It is occasionally seen in puppies with very poor diets or with severe hookworm infections. It is important to understand the underlying cause and to supplement with iron.
What diseases can cause blood loss in dogs?
- The main causes of blood loss in dogs include
- Persistent bleeding due to trauma or injury to blood vessels or damage to internal organs
- Severe infestation of blood-sucking parasites such as fleas, ticks and hookworms
- Tumors (benign or malignant) of the intestines, kidneys, bladder, and spleen that begin to bleed
- Diseases that prevent normal blood clotting
Sudden and severe blood loss can lead to shock or even death if blood loss exceeds 30% to 40% of total blood volume and is not treated quickly with intravenous fluids or transfusions, or both. Obvious causes of severe loss include major injury or surgery. If the cause of blood loss is not obvious, your veterinarian will look for other causes, such as diseases that affect the ability of the blood to clot, bleeding tumors, stomach ulcers or parasites. Internal parasites, such as hookworms in dogs, can cause severe blood loss, especially in puppies. Low, prolonged blood loss eventually leads to iron deficiency anemia. This leads to a deficiency of abnormally small red blood cells and hemoglobin. In young animals this is usually caused by parasites such as fleas, lice or intestinal worms, but in older animals bleeding from gastric ulcers or tumors is more common.
What diseases can cause hemolysis?
- The main causes of hemolysis include
- Autoimmune diseases, especially immune-mediated hemolytic anemia (IMHA or AIHA)
- Blood parasites (e.g., Babesia)
- Chemicals or toxins (e.g., zinc, rat poison, onions or garlic)
- Cancer
Hemolytic anemia occurs when red blood cells are destroyed. They are usually reproducible. Toxins, erythrocyte trauma, infections, immune system defects, and defects in the erythrocyte membrane can all cause hemolytic anemia.
Immune-mediated hemolytic anemia dog
In dogs, the most common cause of hemolytic anemia is immune-mediated. This type of anemia can occur alone or can be caused by tumors, infections, drugs or vaccinations. The body no longer recognizes red blood cells as its own and produces antibodies against circulating red blood cells, causing them to be destroyed.
Dogs with immune-mediated hemolytic anemia usually develop jaundice, sometimes a fever, and may have an enlarged spleen. They may show signs of mild, slow progression and may not seem to be in any pain, or they may suddenly fall into a severe crisis. Your veterinarian will tailor the treatment plan to the animal's signs. Any underlying infection will be treated and unnecessary medication will be discontinued. Intravenous fluid therapy and supplemental blood transfusions may be started if necessary. Medications are also given to suppress the immune system to stop the destruction of red blood cells.
A piece that has been dislodged from the blood clot (called a pulmonary thromboembolism) blocks a blood vessel in the lung, which is a risk in dogs with immune-mediated hemolytic anemia. The underlying cause is not known, but supportive care through fluid replacement and blood transfusions can reduce the risk. Fluids are important to keep the kidneys functioning properly and to protect them from high levels of circulating bilirubin (the red-yellow pigment in the blood that causes jaundice). Anticoagulants may also be given if there is a high risk of clot formation.
Immune-mediated hemolytic anemia is a serious disease that causes death in 20-75% of affected animals. The risk of death depends on the signs seen, but a rapidly declining red blood cell count, moderate to high white blood cell count, abnormal bruising and excessive clotting may indicate a high risk. Your pet's veterinarian may need to refer your dog to an internal medicine specialist.
Homozygous Hemolytic Anemia
Homozygous immune hemolysis occurs when antibodies attack the red blood cells of another individual of the same species. Neonatal isoerythrocytolysis is an example of this disease and is rarely seen in dogs. It is caused by the mother's colostrum (the antibody- and mineral-rich yellowish fluid produced after delivery and before the production of true milk) containing antibodies against the newborn's red blood cells. The antibodies are produced in the mother's body during a mismatched blood transfusion. Newborns with neonatal isoerythrocytolysis are normal at birth but develop severe hemolytic anemia and become weak and jaundiced within 2 to 3 days. A veterinarian can perform tests to confirm the diagnosis. Treatment consists of stopping any colostrum while supportive care is given through blood transfusions. Neonatal isoerythrocytolysis can be avoided by withholding colostrum from the puppy's own mother and giving antibody-free colostrum. Before allowing the newborn to receive maternal colostrum, the veterinarian can perform tests to check for homozygous immune hemolysis.
Microangiopathy hemolytic anemia dog
Microangiopathic hemolysis occurs when red blood cells are damaged due to turbulent flow through abnormal blood vessels. It is seen in dogs with severe heartworm infections, vascular tumors (e.g., hemangiosarcoma), distorted spleens, and diffuse intravascular coagulation, in which small blood clots form throughout the bloodstream, blocking small vessels and consuming platelets and clotting factors needed to control bleeding. Treatment requires correction of the underlying disease.
Metabolic causes of hemolysis
Phosphorus deficiency in the blood leading to red blood cell destruction or starvation can be seen in dogs with diabetes mellitus, hepatic lipid deposition disorders (disorders of fat metabolism in the liver) and refeeding syndrome (chemical and humoral abnormalities that occur during recovery from fasting)). The recommended treatment is to provide additional phosphorus by mouth or injection depending on the severity of the disease.
Toxins (drugs, plants, chemicals)
Many classes of drugs can cause anemia if accidentally ingested or if their prescribed use is not closely monitored. These include common human and animal drugs such as acetaminophen, aspirin, naproxen, penicillin, and many other antibiotics and antiparasitic agents. Other toxins that cause anemia include plants such as oak, red maple and fern; foods such as fava beans and onions; chemicals; and heavy metals such as copper, lead, selenium and zinc. When anemia is suspected, it is always important to provide your veterinarian with as complete a history as possible to help identify the cause.
Infections
Many infections (caused by bacteria, viruses, or other organisms) can cause anemia by either directly damaging red blood cells (causing their destruction) or by affecting the elements in the bone marrow that produce red blood cells. For example, in dogs, infections involving certain organisms in the genera Erysipelas and Babesia can cause anemia.
Inherited diseases
Several inherited red blood cell disorders cause anemia. Pyruvate kinase (enzyme) deficiency is seen in Bassinghounds, Beagles, Western Highland White Terriers, Cairn Terriers, and other breeds. Phosphofructokinase (enzyme) deficiency is seen in English Springer Spaniels. Deficiencies in these enzymes can lead to shortened red blood cell life span and regenerative anemia. In dogs with phosphofructokinase deficiency, the sudden destruction of red blood cells is caused by the high blood pH produced by overexcitement or after exercise. If this condition is minimized, these dogs may have a normal life expectancy. There is no treatment for pyruvate kinase deficiency and affected dogs have a shortened life span due to bone marrow abnormalities.
Non-regenerative anemia dog
Non-regenerative anemia can be caused by nutritional deficiencies, chronic disease, kidney disease, or bone marrow disease.
Nutritional deficiencies
Nutritional deficiency anemia occurs when the nutrients required for red blood cell formation are insufficient. The anemia develops gradually and may initially be regenerative but eventually becomes non-regenerative. Starvation causes anemia through vitamin and mineral deficiencies and a negative balance of energy and protein. The deficiencies most likely to cause anemia are iron, copper, vitamin B12, vitamin B6, riboflavin, niacin and vitamin E.
Iron deficiency is the most common deficiency in dogs. It is rarely nutritious - it most commonly follows blood loss (see blood loss anemia). Young animals do not store much iron, and milk contains very little iron. Your veterinarian may recommend oral iron supplements for anemic newborns. Your veterinarian will also look for any hidden sources of blood loss and treat them if needed.
B vitamin deficiencies are rare. Some medications, such as anticonvulsants and drugs that interfere with B vitamin metabolism, may cause anemia. Malabsorption of vitamin B12 has been reported in giant schnauzers. These dogs respond to injections of vitamin B12.
Chronic disease anemia dog
Anemia caused by long-term (chronic) disease is usually classified as mild to moderate and non-regenerative. It is the most common form of anemia in animals. Anemia may occur following long-term inflammation or infection, tumors, liver disease, or hormonal disorders such as hyperadrenocorticism or hypoadrenocorticism (adrenal disease) or hypothyroidism (low thyroid function). Proteins called cytokines, produced by inflammatory cells, lead to decreased iron availability, red blood cell survival and bone marrow regeneration, resulting in anemia. Treatment of the underlying disease leads to correction of the anemia. There are also medications that stimulate red blood cell production, but they may cause side effects.
Anemia with kidney disease dog
Chronic kidney disease is a common cause of non-regenerative anemia in animals. Animals with kidney disease produce less of a renal hormone called erythropoietin, which stimulates the development of red blood cells in the bone marrow and leads to anemia. A synthetic form of the hormone has been used for treatment. Animals receiving treatment require iron supplementation to support red blood cell production.
Bone marrow disorders
Bone marrow disease or failure from any cause may result in non-regenerative anemia and a decrease in the number of all types of blood cells (red blood cells, white blood cells and platelets). With extensive bone marrow involvement, white blood cells are affected first, followed by platelets and finally red blood cells.
Aplastic anemia (anemia in which the bone marrow has a reduced ability to produce all blood cells) has been reported in dogs. Most cases have no known cause, but some are caused by infection, drug therapy, toxins, or total body irradiation. The immune system may also be involved in the development of this disease. This disease is diagnosed by collecting bone marrow samples. To treat this condition, the underlying cause must be identified and eliminated. Supportive care, such as antibiotics and blood transfusions, and medications that suppress the immune system may also be required. Medications that stimulate the bone marrow may be used until the bone marrow recovers. If there is no known cause of the disease or bone marrow recovery is unlikely (e.g., pau d'arco poisoning in dogs), a bone marrow transplant may be helpful if a suitable donor is available. However, bone marrow transplantation may not be available in all areas.
In pure red blood cell aplasia, only red blood cells or red blood cell producing elements are affected. It is characterized by non-regenerative anemia with a severe reduction of red blood cell-producing elements in the bone marrow. It has been reported in dogs. Immune-related cases usually respond to treatments that suppress the immune system. Severe cases may require supportive therapy, such as blood transfusions. A synthetic hormone that stimulates blood cell production has been reported to cause impaired regeneration of pure red blood cells in some dogs. Discontinuation of hormone therapy may eventually lead to recovery in some animals.
Primary leukemia is a type of cancer in which abnormal white blood cells replace normal blood cells. This causes anemia and a lack of normal white blood cells and platelets. Primary leukemia is uncommon, but has been reported in dogs. Leukemia can develop in the bone marrow or lymphatic system and is classified as either acute (sudden and usually severe) or chronic (long-lasting and usually less severe symptoms). Acute leukemia, in which the bone marrow is filled with immature blood cells, usually responds poorly to chemotherapy. In animals that do respond, the duration of remission is usually very short. In dogs with acute lymphoblastic leukemia, the most common type of acute leukemia has a response rate to chemotherapy of about 30%, with about half of the dogs surviving for at least 4 months. Other types of acute leukemia are less common and much less responsive to treatment. Chronic leukemia, in which one blood cell lineage has a greatly increased yield, is less likely to cause anemia and is more sensitive to treatment.
Myelodysplasia (also known as myelodysplastic syndrome) is a bone marrow disorder in which there is a defect in the growth and maturation of hematopoietic cells in the bone marrow. This can lead to non-regenerative anemia or a shortage of white blood cells or platelets. It is considered a pre-leukemia syndrome (occurs before the full development of leukemia). Myelodysplasia occurs in dogs, cats and humans. The disorder may be the result of a mutation in stem cells or may be caused by tumors in other organs or by drug therapy. Some dogs respond to treatment with synthetic hormones and steroids. Supportive care with blood transfusions may be helpful. Survival rates vary, as bone marrow dysplasia can develop into leukemia. Many animals with this disease will fall asleep or die from infection, bleeding or anemia.
When the normal bone marrow components are replaced by fibrous (scar) tissue, bone marrow fibrosis can lead to bone marrow failure. It may be the initial disease or the result of cancer, immune-mediated hemolytic anemia (see immune-mediated hemolytic anemia), total body irradiation, or hereditary anemia. Diagnosis can be made by bone marrow biopsy, a procedure that requires anesthesia. Treatment depends on the underlying cause, but usually involves suppression of the immune system. Because suppression of the immune system increases your pet's chances of contracting other diseases, follow your veterinarian's recommendations carefully to control exposure to disease-causing agents.
References:
1. Kidney Disease (Chronic & Acute) - WebMD
2. Anemia in Chronic Kidney Disease: Treatment and More
See also:
1. 9 Best At-Home Kidney Tests Buyers Guide In 2022
2. Can I take anemia tests at home?
3. What Is Blood Test For Iron Called?