What is Non-Regenerative Anemia?
Anemia is a decrease in the mass of red blood cells, the result of lack of production, loss of red blood cells, or destruction of red blood cells. There are two types of anemia: regenerative and non-regenerative. With regenerative anemia, alternatively, the bone marrow responds to the anemia by increasing production of red blood cells and releasing reticulocytes (immature red blood cells that don’t have a nucleus). Regenerative anemia can be caused by a hemorrhage or hemolysis (the rupture or destruction of blood cells). In non-regenerative anemia, the cause is usually a decrease in erythropoietin (a hormone controlled by the kidneys that influences red blood cell production as a response to low oxygen in tissues) or bone marrow abnormalities. The bone marrow does not effectively respond to the decrease levels of red blood cells.
Non-regenerative anemia is a deficiency of the red blood cells where the bone marrow is not appropriately addressing the deficiency by increasing red blood cell production and releasing reticulocytes. Symptoms include lethargy, jaundice, fever, pale mucous membranes, and abnormal pulses.
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Symptoms of Non-Regenerative Anemia in Dogs
Symptoms vary depending on the degree, duration, and cause of the anemia, but may include:
- Tachycardia (fast heart rate)
- Pale mucous membranes
- Abnormal peripheral pulses
- Hypotension (low blood pressure)
- Splenomegaly (enlarged spleen)
- Abdominal distension
- Heart murmur
Non-regenerative: Non-regenerative anemia is determined by the absence of reticulocytosis, indicating that erythropoiesis (red cell production) is not functioning properly. Non-regenerative anemia develops slowly and has many potential causes.
Regenerative: Regenerative anemia is characterized by reticulocytosis, a condition where reticulocytes (immature red blood cells) are increased in circulation. This indicates that the body is responding appropriately to the anemia by releasing red blood cells (before they have matured) to compensate for the lower levels in the blood stream. These reticulocytes are polychromatophilic (they have an affinity to multiple acid, neutral and/or basic stains) on routine blood tests.
Causes of Non-Regenerative Anemia in Dogs
- Anemia of chronic disease/anemia of inflammation: This is the most common cause of non-regenerative anemia, typically shares similarities with iron deficiencies
- Absolute iron deficiency: This cause of iron deficiency in dogs is typically caused by chronic blood loss such as in gastrointestinal disease, hookworms, neoplasia, and ulcerations (can cause hemorrhages which lead to iron deficiency)
- Chronic renal failure: In cases of chronic renal failure, a decrease in erythropoietin may cause non-regenerative anemia
- Neoplasia: Non-regenerative anemia can be a complication of cancer, though this is not the case for all cancers; anemia related to cancers is the result of bleeding or hemolysis caused by the neoplasia
- Endocrinopathies: Endocrine diseases such as hypothyroidism, diabetes mellitus, and hypoadrenocorticism, can be associated with non-regenerative anemia
- Liver disease: Non-regenerative anemia caused by liver disease occurs most regularly in cases of chronic liver disease
- Infection of erythropoietic cells: Some viruses can cause infection in the erythropoietic cells, causing non-regenerative anemia
- Disease or toxic injury to bone marrow: Any affliction to bone marrow can cause non-regenerative anemia because it inhibits the bone marrow’s ability to produce red blood cells
Diagnosis of Non-Regenerative Anemia in Dogs
Your veterinarian will likely ask questions to establish a complete medical history. Some of these questions may focus on symptoms, exposure to certain toxins (such as rodenticides, heavy metals, or toxic plants), current drug treatments, vaccinations, history of travel, or previous illnesses. In addition, the following diagnostic tests may be used:
- Physical exam
- Complete blood count, particularly with focus on abnormalities and possible red blood cell parasites
- Bone marrow evaluation
Analysis of red blood cells will focus on size and hemoglobin concentration. Complete analysis of the red blood cells will help to identify or rule out potential causes, including macrocytosis (increase in mean corpuscular volume) which suggests regenerative anemia, microcytosis (decrease in mean corpuscular volume) which indicates anemia from iron deficiency, lead poisoning established through abnormalities in hemoglobin concentration, and oxidative injury indicated by Heinz body formation.
Treatment of Non-Regenerative Anemia in Dogs
Treatment depends on the underlying cause and severity of the regenerative anemia, as well as any underlying conditions that are causing or influencing the anemia, which may include cancer, liver disease, and renal failure. Treatment could include fluid therapy and, in many cases, blood transfusions. Treatment of the cause will need to be considered, and may need to be addressed before the anemia. Recovery will likely include periodic blood transfusions, though that depends on the cause of the non-regenerative anemia. Prognosis varies, ranging from good to poor.
- Fluid therapy
- Blood transfusions, in severe cases
- Removal of any drugs or irritants that could be causing the anemia, especially in instances where the drug is toxic to the bone marrow
- Most genetic diseases have no real treatment
- Treatment of the underlying causes of the anemia, including liver disease, chronic renal failure, and endocrine diseases
Recovery of Non-Regenerative Anemia in Dogs
Recovery and management will depend largely on the underlying condition. If the anemia cannot be completely treated, your veterinarian will likely require multiple follow up visits for blood transfusions or supplemental therapy to help with the anemia. Depending on the cause, treatment, as well as post-treatment recovery, will vary—cause and follow up treatment will influence prognosis.
Non-Regenerative Anemia Questions and Advice from Veterinary Professionals
My dog was fine one day and the next he wasn't. Listless, weak, pale membranes. dark urine. He appeared to go downhill quickly. Took him to the vet, Hct, Hgb, and RBC low and within two days even lower. He could barely walk. Admitted to hosp. Transfused and became even worse. Had a bone marrow biopsy, didn't appear as abnormal as I expected but def. non-regenerative anemia, actually PRCA, no other cells affected. He was too weak and his body never had a chance to respond to steroid therapy. I lost him. I will never get over this loss and I seek answers everyday regarding my "shusky" How common ins this and why. Can the multi-valent vaccines cause the condition? How come some dogs survive. Why did my pup go downhill so quickly? Does it sound like an IM anemia. I'm always looking for news and new treatments for this dreaded condition. Thank you.
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I have a 5.5 year old American Eskimo. He recently passed out when he got overly excited. Brought him to the vet he has had blood work done, an ultrasound, a blood transfusion...so far we have no answer as to what is causing the anemia. Is a bone marrow test likely to lead to the answer? And is that answer most likely cancer?
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My 2 year old cocker spaniel has been diagnosed with congenital kidney disease along with non regenerative anaemia. She has been on several medications and subq fluids. She had been doing really well until this morning when she is struggling to keep her balance. Would this be the anaemia or the kidney failure that is getting her st long last?
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My 10 year old pitbull was diagnosed with non-regenerative imha 5/15, she was also tested for babesia results pending. Her PCV was originally 18% and has varied from 20-24% but today it was 19%. My question is she had a CBC repeated on 5/18 and her reticulocyte count was up. If her IMHA is non regenerative how is her reticulocyte count up from 2,000 to 27,000. Also she is currently on pred, leflunomide, pecid, cerenia, benedryl, doxy, should i also add cyclosporine? She is anorexic as it is I dont want to upset the balance anymore if it wont be beneficial
An increase in reticulocyte count is consistent with regenerative anaemia. In some cases, abnormal reticulocytes may be present but have low levels of haemoglobin. I cannot advise on you giving cyclosporine as I haven’t examined Dolly and she isn’t under my duty of care; it this point, it is best to wait for the Babesia test results and to discuss the next steps with your Veterinarian. Regards Dr Callum Turner DVM
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