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Anemia Due to Enlarged Blood Cells in Cats


Anemia, Megaloblastic (Anemia, Nuclear Maturation Defects) in Cats


In this disease, red blood cells fail to divide and become abnormally large. These cells are also deficient in necessary DNA material. These giant cells with underdeveloped nuclei are called megaloblasts, or "big cells." Red blood cells are mainly affected, but white blood cells and platelets can also go through changes.


For cats that have anemia associated with feline leukemia virus (FeLV), this type of anemia is expected to occur. The seriousness of the anemia can rang from mild to severe.


Symptoms and Types


  • Loss of appetite (anorexia)
  • Diarrhea
  • Pale skin color
  • Weakness
  • Sore mouth and tongue




  • Deficiencies of Vitamin B-12 and folic acid
  • Leukemia
  • Bone marrow disorder
  • Genetics
  • Drugs such as chemotherapy




Tests will be conducted to rule out the following:


  • All mild to moderate non-regenerative anemias, including those of inflammatory disease, renal disease, and lead poisoning
  • Complete blood counts will be taken and bone marrow aspiration analysis
  • In cats, the major disease to be ruled out is feline leukemia virus


Complete blood count, biochemistry, and urinalysis will examine the following:


  • Whether the anemia mild or moderate
  • Whether the anemia is caused by over-sized cells
  • In cats with feline leukemia: whether the anemia associated with a disorder of the spinal column or, possibly, with a different leukemia
  • Bone marrow biopsy usually reveals variable marrow findings



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