Changes

*'''Immune-mediated disease''' including [[Immune Mediated Haemolytic Anaemia]] and [[Neonatal Isoerythrolysis]].

*'''Immune-mediated disease''' including [[Immune Mediated Haemolytic Anaemia]] and [[Neonatal Isoerythrolysis]].

*'''Infectious agents''' including ''[[Babesia|Babesia spp.]]'' in dogs and cattle, ''[[Feline Infectious Anaemia|Mycoplasma haemofelis]]'' in cats, ''[[Leptospira|Leptospira spp.]]'' in various species and ''[[Clostridium haemolyticum]]'' causing redwater fever in cattle.

*'''Infectious agents''' including ''[[Babesia|Babesia spp.]]'' in dogs and cattle, ''[[Feline Infectious Anaemia|Mycoplasma haemofelis]]'' in cats, ''[[Leptospira|Leptospira spp.]]'' in various species and ''[[Clostridium haemolyticum]]'' causing redwater fever in cattle.

*'''Haemotrophic mycoplasmas.''' (Haemoplasmas) are small bacteria that attach to the external erythrocyte membrane. There are multiple species which vary in pathogenicity. In the cat Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’ are seen most frequently; a further species, ‘Candidatus Mycoplasma haematoparvum-like’ has been reported in the literature. Mycoplasma haemofelis is the most pathogenic, producing anaemia and clinical signs of disease. ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’ may cause some changes in red cell parameters but anaemia is only seen in cats with concurrent disease (Retroviral infection), immunocompromised cats or those receiving corticosteroid therapy. In dogs Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ have been identified and may cause haemolytic anaemia in splenectomised or immunocompromised dogs. The method of choice for diagnosis is PCR using appropriate controls on EDTA blood samples. Previously diagnosis was by examination of air-dried blood smears (not EDTA smears) to search for the organisms. Even in the acute phase, parasitaemia is not always present so it may be necessary to take blood and make smears on 5-7 consecutive days. The organisms are very small and must be distinguished from stain precipitate in Romanowsky stained smears, Howell- Jolly bodies and background debris. They may be seen as very small organisms on the periphery of the erythrocyte or form chains and rings. May-Grunwald or acridine orange stains may increasethe sensitivity of blood film examination. References: [[/en.wikivet.net/NationWide Laboratories|NationWide Laboratories]]

*'''Haemotrophic mycoplasmas.''' (Haemoplasmas) are small bacteria that attach to the external erythrocyte membrane. There are multiple species which vary in pathogenicity. In the cat Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’ are seen most frequently; a further species, ‘Candidatus Mycoplasma haematoparvum-like’ has been reported in the literature. Mycoplasma haemofelis is the most pathogenic, producing anaemia and clinical signs of disease. ‘Candidatus Mycoplasma haemominutum’ and ‘Candidatus Mycoplasma turicensis’ may cause some changes in red cell parameters but anaemia is only seen in cats with concurrent disease (Retroviral infection), immunocompromised cats or those receiving corticosteroid therapy. In dogs Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ have been identified and may cause haemolytic anaemia in splenectomised or immunocompromised dogs. The method of choice for diagnosis is PCR using appropriate controls on EDTA blood samples. Previously diagnosis was by examination of air-dried blood smears (not EDTA smears) to search for the organisms. Even in the acute phase, parasitaemia is not always present so it may be necessary to take blood and make smears on 5-7 consecutive days. The organisms are very small and must be distinguished from stain precipitate in Romanowsky stained smears, Howell- Jolly bodies and background debris. They may be seen as very small organisms on the periphery of the erythrocyte or form chains and rings. May-Grunwald or acridine orange stains may increasethe sensitivity of blood film examination. References: [[NationWide Laboratories]]

*'''Inherited defects of red blood cells enzymes''' including pyruvate kinase (which is occur most commonly in West Highland white terriers) and phosphofructokinase (PFK).  

*'''Inherited defects of red blood cells enzymes''' including pyruvate kinase (which is occur most commonly in West Highland white terriers) and phosphofructokinase (PFK).  

*'''Pyruvate Kinase deficiency.''' This is an autosomal recessive genetic disease in dogs causing severe persistant extravascular haemolysis. There is usually moderate to severe anaemia (PCV18-25%) with marked reticulocytosis, possibly due to rapid RBC turnover and splenomegaly. PK-deficient RBCs have a shortened life span with inefficient energy production. Affected dogs are young and usually die by the age of 3 years with, in many cases, myelofibrosis and osteosclerosis. PK deficiency is transmitted as an autosomal recessive trait in many breeds of dogs with the highest prevalence in Basenji’s and Beagle’s. PK deficiency has been reported in the DSH, Abyssinian and Somali breeds of cat. References: [[NationWide Laboratories]]

*'''Pyruvate Kinase deficiency.''' This is an autosomal recessive genetic disease in dogs causing severe persistant extravascular haemolysis. There is usually moderate to severe anaemia (PCV18-25%) with marked reticulocytosis, possibly due to rapid RBC turnover and splenomegaly. PK-deficient RBCs have a shortened life span with inefficient energy production. Affected dogs are young and usually die by the age of 3 years with, in many cases, myelofibrosis and osteosclerosis. PK deficiency is transmitted as an autosomal recessive trait in many breeds of dogs with the highest prevalence in Basenji’s and Beagle’s. PK deficiency has been reported in the DSH, Abyssinian and Somali breeds of cat. References: [[NationWide Laboratories]]

*'''Hypophosphataemia''' which occurs in post-parturient cattle (causing post-parturient haemoglobinuria), with refeeding syndrome and when animals with [[Diabetes Mellitus|diabetes mellitus]] are stabilised with insulin.

*'''Hypophosphataemia''' which occurs in post-parturient cattle (causing post-parturient haemoglobinuria), with refeeding syndrome and when animals with [[Diabetes Mellitus|diabetes mellitus]] are stabilised with insulin.

*Exposure to '''toxins''' including rape and kale (which contain SMCO radicals) in cattle, onions and garlic in dogs and paracetamol in cats.

*Exposure to '''toxins''' including rape and kale (which contain SMCO radicals) in cattle, onions and garlic in dogs and paracetamol in cats.

*'''Microangiopathic anaemia''' which occurs when red blood cells are forced through small meshworks of fibrin as with [[Haemangiosarcoma|haemangiosarcomas]], [[Disseminated Intravascular Coagulation|disseminated intravascular coagulation]] (DIC) or bacterial endocarditis.This is usually a mild, often subclinical anaemia unless there is concurrent haemorrhage from, for example, a tumour. RBCs are damaged as they pass through abnormal vessels or regions of turbulent blood flow, giving rise to schistocytes. These fragmented red cells are phagocytosed by the mononuclear phagocytic system, causing anaemia. Numerous schistocytes in a smear are always significant. References: [[/en.wikivet.net/NationWide Laboratories|NationWide Laboratories]]  

*'''Microangiopathic anaemia''' which occurs when red blood cells are forced through small meshworks of fibrin as with [[Haemangiosarcoma|haemangiosarcomas]], [[Disseminated Intravascular Coagulation|disseminated intravascular coagulation]] (DIC) or bacterial endocarditis.This is usually a mild, often subclinical anaemia unless there is concurrent haemorrhage from, for example, a tumour. RBCs are damaged as they pass through abnormal vessels or regions of turbulent blood flow, giving rise to schistocytes. These fragmented red cells are phagocytosed by the mononuclear phagocytic system, causing anaemia. Numerous schistocytes in a smear are always significant. References: [[NationWide Laboratories]]

Haemolysis usually results in a more strongly regenerative response than haemorrhage and can be differentiated by plasma protein concentrations; these will fall with haemorrhage, but not with haemolysis.

Haemolysis usually results in a more strongly regenerative response than haemorrhage and can be differentiated by plasma protein concentrations; these will fall with haemorrhage, but not with haemolysis.

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.   

===Failure of the bone marrow stem cells to produce erythroid cells===

 

=== Primary Anaemia: Failure of the bone marrow stem cells to produce erythroid cells ===

This occurs in the following conditions:

This occurs in the following conditions:

*'''[[Immune Mediated Haemolytic Anaemia|Pure red cell aplasia]]'''

 

 

*Myelophthisis

*Myelodysplasia

 

 

 

 

'''[[Immune Mediated Haemolytic Anaemia|Pure red cell aplasia]]'''

 

Myelophthisis

 

Myelodysplasia

===Failure of erythrocyte maturation===

===Failure of erythrocyte maturation===