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Regenerative and Non-Regenerative Anaemias (view source)
Revision as of 20:52, 7 March 2022
, 20:52, 7 March 2022no edit summary
The failure to regenerate indicates that there is a failure to produce red blood cells in the bone marrow. Erythrocytes are produced from stem cells in the bone marrow and they then undergo sequential stages of maturation before and after they are released into the circulation.
The failure to regenerate indicates that there is a failure to produce red blood cells in the bone marrow. Erythrocytes are produced from stem cells in the bone marrow and they then undergo sequential stages of maturation before and after they are released into the circulation.
An inadequate degree of reticulocytosis is the essential diagnostic feature. Some reticulocytes may be present but fewer than required for a given degree of anaemia, after sufficient time has elapsed for an erythroid response to have developed. These anaemias are mainly normochromic normocytic. References: [[/en.wikivet.net/NationWide Laboratories|NationWide Laboratories]]
An inadequate degree of reticulocytosis is the essential diagnostic feature. Some reticulocytes may be present but fewer than required for a given degree of anaemia, after sufficient time has elapsed for an erythroid response to have developed. These anaemias are mainly normochromic normocytic. References: [[NationWide Laboratories]]
=== Primary Anaemia: Failure of the bone marrow stem cells to produce erythroid cells ===
=== Primary Anaemia: Failure of the bone marrow stem cells to produce erythroid cells ===
'''Proliferative disorders.''' Can also cause nonregenerative anaemia as neoplastic cells over-run the bone marrow (myelophthisic disease).
'''Proliferative disorders.''' Can also cause nonregenerative anaemia as neoplastic cells over-run the bone marrow (myelophthisic disease).
References: [[NationWide Laboratories]]
'''[[Immune Mediated Haemolytic Anaemia|Pure red cell aplasia]]'''
'''[[Immune Mediated Haemolytic Anaemia|Pure red cell aplasia]]'''
Myelophthisis
'''Myelophthisis'''
'''Myelodysplasia'''
=== Drug-induced Haematological Dyscrasias ===
Many drugs have been found to cause blood dyscrasias in both dogs and cats. Drugs causing irreversible aplastic anaemia include phenylbutazone, meclofenamic acid and oestrogens; oestrogen toxicity may also be reversible. Griseofulvin has been associated with reversible aplastic anaemia. The prognosis for these conditions is generally poor. Oestrogen toxicity whether due to drug administration or a Sertoli cell tumour can cause thrombocytosis 5-7 days after administration/exposure followed by thrombocytopaenia and neutrophilia for 2-3 weeks followed by neutropaenia. Pancytopaenia develops 3-4 weeks after administration/exposure. References: [[NationWide Laboratories]]
=== Infections ===
'''FeLV.''' Responsible for most cases of nonregenerative anaemia in cats. There may be macrocytosis in the absence of reticulocytosis.
'''FIV.''' May be associated with nonregenerative anaemia possibly with concurrent neutropaenia.
=== Secondary Anaemia ===
'''Anaemia of inflammation.''' This is the most common cause of nonregenerative anaemia and may occur with inflammatory or neoplastic disease. It is usually mild to moderate. Macrophages involved in an inflammatory response release cytokines including interleukin-1, interleukin-6 and tumour necrosis factor. These not only initiate fever but cause iron sequestration within macrophages thereby reducing serum iron and restricting iron availability for erythropoiesis.
'''Anaemia of chronic renal disease.''' Ineffective erythropoiesis, shortened RBC life span and blood loss may contribute to this anaemia which may become severe. The mechanism appears to be more complex than a relative deficiency of erythropoietin (EPO), but this type of anaemia may respond to EPO therapy.
'''Anaemia of chronic hepatic disease.''' Coagulation defects due to reduced synthesis of clotting factors in severe hepatic disease may result in haemorrhage. Reduced hepatic function may also lead to deficient levels of nutrients required for haematopoiesis. In dogs with portosystemic shunts, microcytosis is common due to a functional iron deficiency. These dogs have increased hepatic iron but low serum iron, normal total iron binding capacity and a low percentage of transferrin saturation.
'''Hypothyroidism and hyperadrenocorticism.''' These endocrinopathies may result in mild, clinically insignificant anaemia.
References: [[NationWide Laboratories]]
=== Iron Deficiency Anaemia ===
Typically hypochromic microcytic, initially regenerative but may become nonregenerative. This has already been discussed. References: [[NationWide Laboratories]]
===Failure of erythrocyte maturation===
=== Failure of erythrocyte maturation ===
This can occur with:
This can occur with:
*Iron deficiency
*Iron deficiency