Foal Clin Path Flashcards
What is the principle organ of hematopoiesis in utero?
Fetal liver
When does bone marrow contribute to hematopoiesis in utero?
Not until the end of gestation
What adaptations do the equine fetus that facilitate oxygen diffusion across the placenta?
- Lower erythrocyte concentration sof 2,3-diphosphoglycerate— shifts O2 dissociation curve to the left
- Placental countercurrent circulatory pattern
Clinical signs of anemia are what and due to?
— decreased oxygen-carrying capacity of blood
- exercise interolerance, lethargy, weakness, tachycardia, tachypnea
Examples of blood loss that cause anemia in foals
Cesarean section
Fractured ribs: hemothorax, soft tissue hematoma
Bleeding umbilical remnant: external
Trauma: ruptured femoral artery, ruptured gastrocnemeus tendon
Intra-abdominal hemorrhage: ruptured liver or spleen, internal umbilical remnant
Gastrointestinal tract: bleeding gastric ulcers, hemorrhagic enterocolitis, coagulopathy
Thrombocytopenia: alloimmune-mediated, immune-mediated, disseminated intravascular coagulation
Congenital factor deficiency: factor VIII/C, von Willebrand disease
Examples of hemolytic anemia in foals
Neonatal isoertyhrolysis Infection: clostridia spp Disseminated intravascular coagulation Incompatible blood transfusions Autoimmune hemolytic anemia Toxic causes: snake envenomation, rapid dimethylsufloxide administration
Examples of causes of decreased production of rbc as a cause of anemia in foals
Prematurity Anemia of chronic disease Iron deficiency Bone marrow defects associated with maternal administraiton of sulfonamides, pyrimethamine, folic acid Chronic renal disease Fell pony syndrome
Causes for erythrocytosis in foals
Splenic contraction from excitement or handling in addition to dehydration
Hypoxia d/t congenital cardiac dz lead to R to L shunting
(Reported in a hepatic tumor)
Indicators of toxic neutrophils
Dohle bodies
Cytopalsmic vacuolation
Toxic granulation
Basophilic cytoplasm
When are neutrophils functionally mature?
At birth
**phagocytic capacity is limited in foals les than 3 wks of age by opsonic ability of foal’s serum
Phagocytic function of neutrophils is dependent on:
Maturation of serum opsonization factors (ie., complement)
**does not dep on serum IgG
At what degree has lymphopenia should raise suspicion of primary immunodieficiency?
Persistent Lymphopenia < 0.5 x 10^9 cells/L
Severe combined immunodeficiency (SCID) in arabians is inherited through
Autosomal recessive inheritance
SCID foals show decreased function of:
Lymphopenia
Abnormal T & B lymph function test results
**presuckle IgM and other Iggs are not detectable by single radial immunodiffusion (RID) at birth
Fell pony syndrome is associated with:
Decreased major histocompatibility class 2 expression on lymphs and weak T cell response to concanavalin A
Causes of thrombocytopenia in foals
DIC: disseminated intravascular coagulation
Sepsis
Viral infection (EHV-1, equine viral arteritis)
SIRS
Alloimmune thrombocytopenia
Ulcerative dermatitis
Why is alkaline phosphatase (ALP) activity high in foals?
Because of the high osteoblastic activity in growing bone and intestinal development activity & pinocytosis during first 24 hours of life