Anemia Flashcards
What are three variable components that RBC mass depends on?
Splenocontraction
Breed/Age
Exercise level
What % of RBC mass is in the spleen?
30%
Splenocontraction can increase the PCV up to what %?
50%
T/F: Hot blooded horses have a higher PCV than cold-blooded horses
TRUE
Hot-blooded=thoroughbreds
Cold-blooded=draft horses
How many blood groups are in the horse?
8 blood groups
T/F: There is NO true universal donor in the equine species
TRUE
What are the dependent factors of CS development in an anemic horse?
Rate and severity of RBC decrease
What are general CS of acute anemia?
Poor performance, tachycardia, tachypnea, pale MM, lethargy, systolic murmur
T/F: regeneration can be assessed on a peripheral blood smear of the horse?
FALSE
What is a normal characteristic of blood cells on a smear that can be mistaken for agglutination?
Rouleaux formation
What is free hemoglobin associated with?
Intravascular hemolysis
What are the three pathophysioogic mechanisms of anemia?
Inadequate erythrocyte production
Increased erythrocyte destruction
Blood loss
What are the three causes of depression anemia?
Deficiencies in vitamin and minerals essential for RBC production
Chronic/systemic disease interfering with normal erythropoiesis
Damaged bone marrow or bone marrow components
What is TRUE iron deficiency defined by in the horse?
microcytic hypochromic anemia-only seen in late stages
Fe deficient anemia in the horse is most commonly associated with what?
Chronic blood loss from parasites, GI lesions or hemostatic defects
What is another name for functional iron deficiency?
Anemia of inflammatory disease
T/F: Horses with anemia of inflammatory disease commonly have a PCV under 18%
FALSE-doesn’t typically drop under 18%
What is the most common cause of anemia in the horse?
Inflammatory disease
What is the carrier protein responsible for iron transport and distribution in the body
Transferrin
What is the only safe parenteral preparation of iron for the horse?
Iron cacodylate
T/F: Iron supplementation is indicated for anemia of inflammatory disease
FALSE-anemia is of little to no concern
What are two causes of increased red cell destruction?
Oxidative damage or immune mediated mechanisms
How does oxidative damage affect the blood?
Changes iron form ferrous form to ferric form leading to formation of methemoglobin which cannot carry O2.
What are CS of methemoglobin?
Brown discoloration to MM, blood and urine
What are some infectious diseases that cause increased RBC destruction?
EIA, piroplasmosis
What are some toxic agents that cause increased RBC destruction?
Red maple leaves, onions, monensin and phenothiazines
What are some immune causes of increased RBC destruction?
Neonatal isoerythrolysis, IMHA and incompatible blood transfusions
What is the only intraerythrocytic parasitic disease that affects horses?
Piroplasmosis-equine babesiosis
What is the vector for babesiosis?
Tick vectors- Dermatocentor nitens
What are the CS of babesiosis?
Fever, hemolytic anemia, icterus, death
What are four differentials of babesiosis?
Equine granulocytic ehrlichiosis, equine infectious anemia, hemolytic anemia, liver failure
How long post babesiosis infection does it take for antibodies to be detected?
14 days
What is a reportable disease in horses that is also known as swamp fever?
Equine infectious anemia
What is the causative agent of EIA?
Lentivirus of retrovirus family
What cell does EIA target?
Macrophages-integrate into the host genome
How is EIA transmitted?
Interrupted feeding by hematophageous arthropods required Biting insects (tabanids-deer and stable flies) or mosquitoes
What is the mechanism of anemia from EIA?
Immune mediated hemolysis
Decreased intravascular erythrocyte survival time
Decreased bone marrow erythrocyte production
What does acute EIA cause?
Extravascular hemolytic anemia
What are CS associated with acute EIA?
thrombocytopenia, fever, depression, petechial hemorrhage
No anemia typicaly seen
What are CS associated with subacute/chronic EIA?
Recurrent episodes of fever, depression, anemia and icterus, lymphadenopathy, weight loss
What are the two dx tests used for EIA?
Coggins test
ELISA
Which EIA dx test is more sensitive and specific?
ELISA
What is the internationally accepted dx test for EIA?
Coggins test- gold standard test
Why can the Coggins test give false negatives for EIA dx?
Takes about 45 days to produce detectable levels of Ab
What are general recommendations when a horse tests positive for EIA?
Recommended to isolate for life or euthanize
Why must 200 yards be kept between a EIA horse and a non-infected horse?
The double fencing pasture method is important because the flies will only fly around 200 meters before turning back around to re-feed on the previous horse
