Flashcards in Case 35 + ITP Deck (11):
What is the pathophysiology of immune thrombocytopenic pupura?
-autoimmune disorder w/ accelerated platelet destruction via phagocytosis of antibody coated platelets by the reticuloendothelial system (RES) in spleen, liver and bone marrow
-autoantibodies (mainly IgG) against common platelet glycoproteins and, therefore, cross-react with allogeneic platelets
What are causes of increased platelet destruction?
-immune mediated: autoimmune, alloimmune, drug induced
-non-immune mediated: endotoxemia or exotoxemia, hemophagocytosis, DIC, associated with fragmentation hemolysis, artificial surfaces, misc
What is the differential dx of decreased platelet count due to decreased production? What do you see in blood smear?
smear: small platelets, decreased MEGs
What is the differential dx of decreased platelet count due to increased destruction? What do you see in blood smear?
-fragmentation hemolytic anemia
smear: big platelets, increase MEGs
What are the causes of fragmentation hemolytic anemia with thrombocytopenia?
Mechanical valves and/or paravalvular cardiac “leaks”
Disseminated intravascular coagulation
Thrombotic thrombocytopenia purpura
Hemolytic uremic syndrome
Multifocal endothelial disease
pre-eclampsia and eclampsia
What is the differential dx of decreased platelet count due to ineffective production? What do you see in blood smear?
smear: variable MPV
What is the differential dx of decreased platelet count due to redistribution? What do you see in blood smear?
-due to portal hypertension, storage disease or associated with marrow disorder
What are causes of thrombocytopenia secondary to decreased total thrombopoiesis?
Marrow infiltration or replacement
Certain drugs or alcohol
What are treatments of ITP?
-other drugs...like vincristine, azathioprine
What is the difference between acute and chronic ITP?
abrupt onset bleeding
hemorrhagic bullae in mouth present in severe cases
platelet ct is low
Eos and lympocytosis
duration: self limiting, 2-24 weeks, spontaneous remission
more females than males
insidious onset of bleeding
hemorrhagic bullae usually absent
platelet ct low
Eos and lympocytosis uncommon
lasts months to years