Causes & Remedies for Cat Anemia: Effective Solutions
The causes of anemia in cats can be broadly categorized into three main types: reduced red blood cell production, increased red blood cell loss, and enhanced red blood cell destruction. Reduced red blood cell production often leads to nonregenerative anemia in cats. Anemia resulting from increased red blood cell loss and destruction typically starts to regenerate within the first 3 to 5 days after an injury, but chronic gastrointestinal bleeding can lead to nonregenerative anemia due to iron deficiency.
When red blood cell production is diminished, it is often due to bone marrow damage. Causes of bone marrow damage in cats include:
1. Kidney failure, which can lead to normocytic, normochromic anemia due to decreased erythropoietin secretion.
2. Myelofibrosis, where new tumors or fibrosis replace the bone marrow, causing sideropenic anemia.
3. Iron deficiency, which typically results in microcytic, hypochromic anemia, though it can occasionally present as normocytic, normochromic anemia.
4. Inflammatory diseases, often causing mild to moderate normocytic, normochromic anemia with a hematocrit of no less than 49% to 59%.
5. Infectious factors, with feline leukemia virus being the most common.
6. Immunemediated diseases.
7. Toxins, such as chloramphenicol and chemotherapy drugs.
Red blood cell loss is often due to gastrointestinal bleeding, urinary tract bleeding, or internal bleeding (such as splenic rupture or hemothorax). Chronic gastrointestinal bleeding may be accompanied by thrombocytosis and elevated urea nitrogen to creatinine ratios. Causes include:
1. Hereditary clotting and platelet disorders.
2. Acquired clotting and platelet disorders, including rodenticide poisoning, immunemediated thrombocytosis, and liver disease.
3. Neoplasms, including hemangiosarcoma, small intestinal lymphosarcoma, and small intestinal adenocarcinoma.
4. Severe ulcerative gastroenteritis, such as eosinophilic gastroenteritis.
5. Trauma.
6. Felinespecific F urinary tract diseases.
7. Parasitic infections, particularly fleas and hookworms.
Clinical symptoms of blood loss include petechiae, ecchymosis, nosebleeds, vomiting blood, melena, hematomas, and joint hematomas. Internal bleeding may present as abdominal distension or dyspnea.
Increased red blood cell destruction can be attributed to several factors:
1. Primary immunemediated diseases, which are relatively rare in cats.
2. Secondary immunemediated diseases following infections, neoplasms, or drug exposure, with infectious diseases being the most common cause of secondary immunemediated hemolytic anemia in cats.
3. Genetic red blood cell defects, such as osmotic fragility defects and pyruvate kinase deficiency, particularly in Somalis and Abyssinians, which can sometimes be misdiagnosed as immunemediated hemolytic anemia.
4. Hypophosphatemia, which can trigger acute hemolysis after refeeding following longterm anorexia or during insulin therapy for diabetic ketoacidosis.
5. Toxininduced oxidative damage to red blood cells and the formation of Heinz bodies. Cats, with more sulfhydryl groups in their hemoglobin than dogs, are more susceptible to oxidative damage. Oxidative toxins include acetaminophen, zinc, onions, garlic, and local anesthetics.
6. Microangiopathic damage to red blood cells. Endothelial damage in small blood vessels can lead to fibrin deposition and platelet aggregation. As red blood cells pass through damaged vessels, they are prone to fragmentation, sometimes even visible as schistocytes in a blood smear.
7. Microvascular disease causing red blood cell damage. Endothelial damage in small blood vessels can lead to fibrin deposition and platelet aggregation. As red blood cells pass through damaged vessels, they are prone to fragmentation, sometimes even visible as schistocytes in a blood smear.
Clinical symptoms of hemolysis include splenomegaly, jaundice, hemoglobinemia, and hemoglobinuria. Compared to dogs, cats have smaller, centrally pale red blood cells, so spherocytes are considered abnormal in cats.
