Equine anaemia Flashcards Preview

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Flashcards in Equine anaemia Deck (28)
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What are the causes of external blood loss in horses?

External wound involving large artery
Guttural pouch mycoses
Post surgical haemorrhage - castration
Into GI lumen
Haematuria - uncommon in horses


What are the cavities that blood can bleed into in horses?

Peritoneal, thoracic and urogenital


What are the causes of haemoperitoneum?

Spleen or liver rupture, mesneteric vessel rupture, uterine artery rupture, neoplasm, internal bleeding following castration, Erosion of a large vessel by abscess or neoplasm or rupture of aneurysm, Coagulopathy


What are the causes of haemothorax?

Secondary to a traumatic event, Erosion of a large vessle by abscess/neoplasm or aneurysm rupture, Rupture of aorta/pulmonary vessel, Coagulopathy, Neoplasia


What are the causes of blood loss via urogenital tract?

Uterine artery rupture before/after parturition


What are the causes of immune-mediated haemolytic anaemia (IMHA) in horses?

Primary - uncommon autoimmune process
Secondary due to alterations in RBC membrane by primary infections/neoplasia/other immune-mediated disease process, antigen-antibody complex deposition on surface of RBCs or drugs that cause immunoproteins to react indirectly with RBCs


What is the treatment for IMHA in horses?

Discontinue all treatments if possible, treat primary condition, blood transfusion if necessary, immunosuppression if necessary using corticosteroids


What are Heinz bodies?

Precipitations of oxidatively denatured haemoglobin


What causes Heinz bodies in horses?

Rarely used drugs (methylen blue, phenothiazine) or plants horses rarely consume in sufficient concentrations (onions, Brassicas), Red Maple Leaf Toxicity in USA


What is Equine Infectious Anaemia (EIA)?

Exotic to the UK and is caused by Equine Infectious Anaemia virus which is a lentivirus and causes a persistent infection with no treatment


What are the characteristics of anaemia due to chronic disease?

Most common cause of anaemia in adult horses, mild-moderate non-regenerative anaemia, not severe enough to cause clinical signs


What is the pathogenesis of anaemia due to chronic disease?

Iron sequestration, defective erythropoietin response, decreased RBC life span


What is the treatment for anaemia due to chronic disease?

Treat the primary disease


What is the cause and treatment of Iron Deficiency Anaemia?

Chronic external blood loss
Oral iron supplementation


How developed is the neonatal foal immune system?

Capable of mounting an immune response but no antigenic memory so relies on ingestion of colostrum to allow time for foal to start to produce its own antibodies


What is the composition of colostrum?

Mainly IgG, some IgA and IgM


How is the Ig absorbed from the colostrum?

Foals suckle withing 1-3 hours after birth and consume 1-2L and specialised enterocytes allow absorption of large IgG molecules with maximal capacity at 6 hours


What is the consequence of failure of passive transfer in horse?

Predisposes foal to infectious disease especially bacteraemia/sepsis, septic arthritis, diarrhoea and pneumonia


What can cause failure of passive transfer in foals?

Lack of colostrum/poor quality colostrum (premature)
Failure of foal to nurse (PAS, orthopaedic problem, mare temperament)
Failure of absorption as GIT of foal unable to absorb colostrum


How is failure of passive transfer in foals diagnosed?

Measurement of IgG concentrations
<4g/l = FPT, 4-8g/l = partial FPT,


What is the treatment for failure of passive transfer in a foal?

Less than 12-18 hours = oral colostrum
>12-18 hours = IV plasma, 1L will increase IgG conc by 2g/l
Treat underlying disease (antibiotics for infections)


What is neonatal isoerythrolysis?

Haemolytic disease of foals caused by destruction of foals RBCs by antibodies present in colostrum


What causes neonatal isoerythrolysis?

Blood group incompatibility of mare and foal in multiparous mares that have been sensitised to foals RBC antigens during pregnancy


What is the sequence of events causing neonatal isoerythrolysis?

Foal inherits RBC antigen from sire that is different to mare, antigen must be strongly antigenic (Aa,Qa)
Mare must be exposed to RBC antigen and produce antibodies to it and are contained in mare's colostrum
Foal ingests colostrum, antibody-coated RBC removed from circulation or lysed intravascularly


What are the clinical signs of neonatal isoerythrolysis?

Normal at birth, develop signs withing 1st 4 days of life
Weakness, lethargy, increased HR and RR, icterus, pale MM
Time of onset and severity dependent on amount of antibodies ingested and affinity of antibodies to RBC


How is neonatal isoerythrolysis diagnosed?

Clinical signs, haemolytic cross match, thrombocytopaemia may accompany anaemia


How can neonatal isoerythrolysis be prevented?

Check for antibodies in late gestation
Prevent foal from nursing in first 24-48hours and provide alternative colostrum


What is severe combined immunodeficiency?

Affects Arab foals, autosomal recessive
Lack of functional T and B lymphocytes
Can test for SCID gene