Changes

IMHA may occur as a '''primary''' disease with no apparent cause or it may be '''secondary''' to another systemic insult. Possible secondary causes of IMHA include bacterial and parasite infections (including ''[[Babesia canis]]'' in dogs and ''[[Feline Infectious Anaemia|Mycoplasma haemofelis]]'' in cats), adverse drug reactions, neoplasia (especially myeloproliferative and lymphoproliferative disease) and live vaccines, although the association between vaccination and immune-mediated disease remains controversial.   

IMHA may occur as a '''primary''' disease with no apparent cause or it may be '''secondary''' to another systemic insult. Possible secondary causes of IMHA include bacterial and parasite infections (including ''[[Babesia canis]]'' in dogs and ''[[Feline Infectious Anaemia|Mycoplasma haemofelis]]'' in cats), adverse drug reactions, neoplasia (especially myeloproliferative and lymphoproliferative disease) and live vaccines, although the association between vaccination and immune-mediated disease remains controversial.   

The majority of cases of IMHA affect only the circulating red blood cells resulting in a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] as the bone marrow stem cells respond to the disease. In a small number of cases, antibodies are produced that affect the stem cells of the [[Erythropoiesis|erythroid lineage]] in the bone marrow, resulting in a non-regenerative anaemia that still bears many of the same clinical features as IMHA. Although the two diseases have been considered separately in the past, they really represent two ends of a spectrum of immune-mediated disease directed at cells of the erythroid line.

The majority of cases of IMHA affect only the circulating red blood cells resulting in a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] as the bone marrow stem cells respond to the disease. In a small number of cases, antibodies are produced that affect the stem cells of the [[Erythropoiesis|erythroid lineage]] in the bone marrow, resulting in a non-regenerative anaemia that still bears many of the same clinical features as IMHA. Although the two diseases have been considered separately in the past, they really represent two ends of a spectrum of immune-mediated disease directed at cells of the erythroid line.

The widespread lysis of red blood cells causes disease in the following ways:

The widespread lysis of red blood cells causes disease in the following ways:

====Haematology====

====Haematology====

Affected animals have a reduced [[Packed Cell Volume|packed cell volume]] (PCV) or haematocrit (HCT) and often a reduced haemoglobin concentration.  IMHA causes a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] and evidence of macrocytosis (increased MCV) should be apparent after 48-72 hours in dogs. A blood smear is extremely useful in evaluating cases of IMHA as '''spherocytes''' [http://www.medvet.umontreal.ca/clinpath/banq-im/hematology/SpherocytesE.htm Spherocytes]are often visible. These small, dense red blood cells are formed due to partial phagocytosis of red blood cells by the MPS. Polychromasia should also be visible on a blood smear from an animal undergoing regeneration and reticulocytosis can be confirmed using a supravital stain such as new methylene blue.

Affected animals have a reduced [[Packed Cell Volume|packed cell volume]] (PCV) or haematocrit (HCT) and often a reduced haemoglobin concentration.  IMHA causes a strongly [[Regenerative and Non-Regenerative Anaemias|regenerative anaemia]] and evidence of macrocytosis (increased MCV) should be apparent after 48-72 hours in dogs. A blood smear is extremely useful in evaluating cases of IMHA as [http://www.medvet.umontreal.ca/clinpath/banq-im/hematology/SpherocytesE.htm spherocytes]are often visible. These small, dense red blood cells are formed due to partial phagocytosis of red blood cells by the MPS. Polychromasia should also be visible on a blood smear from an animal undergoing regeneration and reticulocytosis can be confirmed using a supravital stain such as new methylene blue.

Reactive [[Platelet Abnormalities|thrombocytosis]] and leucocytosis may be present with any cause of anaemia.

Reactive [[Platelet Abnormalities|thrombocytosis]] and leucocytosis may be present with any cause of anaemia.

==References==

==References==

<references/>

<references/>

{{review}}

{{review}}