hematology Flashcards
pathophys of immune thrombocytponeic purpura?
autoimmune production of IgG against platelet antigens, ->consumed by splenic macrophages -> thrombocytopenia
which cells produce the antibodies in ITP?
splenic plasma cells
Lab findings in ITP
Decreased platelet count
Normal PT/PTT
Increased megakaryocytes on bone marrow biopsy
Treatment for ITP?
Corticosteroids, IVIG
-splenectomy for refractory cases - eliminates the site of the antibody production
Name two types of microangiopathic hemolytic anemia
- HUS
- TTP
thrombotic thrombocytopenic purpura pathophs (TTP)?
Decreased ADAMTS13 - ADAMST13 normally cleaves vWF multimers into smaller monomers for degradation. With decreased ADAMTS13, uncleaved monomers lead ot abnormal platelet adhesion - > microthrombi -> sheering of rbcs
Decreased ADAMTS13 is usually due to…
an acquired autoantibody
who usually gets HUS?
children with e coli O157:H7 infection
Clinical findings of microangiopathic hemolytic anemia (HUS and TTP)?
- skin and mucosal bleeding
- hemolytic anemia
- fever
- renal insufficiency (HUS)
- CNS abnormalities (TTP)
lab findings of microangiopathic hemolytic anemia (HUS and TTP)?
- thrombocytopenia with increased bleeding time
- normal PT/PTT
- anemia with schitocytes
- increased megakaryocytes on biopsy
uremia disrupts which parts of platelet function?
both adhesion and aggregation
bernard-soulier syndrome is due to a genetic deficiency of…
GPIb
what is the cause of glanzmann thrombasthenia?
genetic GPIIb/IIIa deficiency
Hemophilia A is a X linked deficiency of…
factor VIII
Hemophilia B =
Christmas Disease
Hemophilia B is a deficiency of…
factor IX
What is the most common coagulation factor inhibitor?
anti-FVIII
How can you differentiate hemophilia A from a coagulation factor inhibitor (autoantibody against factor VIII)
Upon mixing the patients plasma with normal plasma, the PTT will not correct due to the presence of the antibody (whereas it would correct with hemophilia A)
Most commonly inherited coag disorder?
Von Willebrand disease- genetic vWF deficiency
inheritance of most common type of vWF defieincy?
AD
lab findings of vWF disease?
- increased bleeding time
- increased PTT, normal PT
- abnormal ristocetin test
why is PTT increased in vWF disease?
VWF normally stabilizes factor VIII
treatment of vWF disease?
desmopressin
function of alpha 2 antiplasmin?
inactivates plasmin
why may an alcohol have decreased alpha 2 antiplasmin?
liver cirhossis - not produced
plasmin function
cleaves serum fibrinogen
presentation of disorder of fibrinolysis?
- increased PT/PTT (plasmin destroys coag factors)
- increased bleedining time (blocks aggregation)
- increased fibrinogen split products with NORMAL D-dimer
why is d-dimer normal in disorders of fibrinolysis
Fibrin thrombi are absent in the case of disorder of fibrinolysis therefore D-dimers are not formed
treatment for disorders of fibrinolysis?
aminocaproic acid — blocks activation of plasminogen
A deficiency of cystathione beta synthase results in high levels of…
homocysteine
estrogen induces increased production of…
coagulation factors
name the microcytic anemias
- iron deficiency
- anemia of chronic disease
- sideroblastic anemia
- thalasemmia
what is the cofactor needed for ALAS?
B6
How does lead poisoning cause sideroblastic anemia?
-lead inhibits ALAD and ferrochelatase - needed for heme synthesis
if you have alpha thalasemia with 3 genes deleted, what will your Beta chains for?
tetramers - HbH - will damage RBCs
if you have alpha thalasemia with 4 genes deleted, what will form?
Hbarts - tetramers of gamma chains
How does alpha thalesemia with 4 genes deleted present?
Death in utero via hydrops fetalis
if you have alpha thalasemia with two genes deleted how will you present?
mild anemia with increased RBC count
alpha thalassemia is usually due to a gene…
deletion