Immune Mediated Diseases Flashcards
what causes IMHA?
type 2 hypersensitivity reaction
what is the pathogenesis of IMHA?
RBCs are destroyed and anemia develops because autoantibodies are made against the animals own RBCs
what is the prognosis for an IMHA case?
can be variable but can be poor to guarded
true or false.
pulmonary thromboembolism is associated with 50% of all IMHA deaths.
true
what are some PE findings with IMHA?
- fever
- enlarged spleen, liver and lymph nodes
- icterus or pale mm
- signs of tissue hypoxia and increased cardiac output (tachypnea and tachycardia)
- grade II to III systolic murmur, S3 gallop (due to anemia)
what do the autoantibodies produced in IMHA target specifically?
glycophorin - the glycoprotein that spans the plasma membrane
attachment of the antibody to RBC in IMHA can cause what?
- extravascular hemolysis
- intravascular hemolysis
- intravascular RBC agglutination
whats the pathogenesis of intravascular hemolysis in IMHA?
IgM attaches to RBC -> activates the complement system -> MAC complex is formed -> RBC lysed
what does intravascular hemolysis in IMHA lead to ?
hemoglobinemia and hemoglobinuria
what is the more common type of IMHA dogs get?
primary IMHA which is idiopathic (50-70% of cases)
what is the more common type of IMHA cats get?
secondary IMHA which can be from infections, neoplasia, neonatal isoerthrolysis or incompatible blood transfusions
how do we diagnose IMHA ?
- CBC - look for anemia, reticulocyte count
- blood smear - look for spherocytes or anisocytosis
- serum and urine - look for hemoglobinemia or hemoglobinuria
- agglutination tests
- coombs test
if you have an animal that is anemic and shows spherocytes on your blood smear, should you always assume IMHA?
yes
how can we determine if IMHA is primary vs secondary ?
- look for evidence of coagulation issues
- bone marrow cytology
how do we treat IMHA ?
primary IMHA
- may need to give a blood transfusion to replace O2 carrying capacity of blood (can give packed RBCs or whole blood, may need 2-3 transfusions)
- needs immunosuppression (ex. pred)
- address the coagulation issues
- may possibly need a splenectomy
