Pathoma: Other disorders of hemostasis Flashcards
What does HIT stand for?
heparin-induced thrombocytopenia
What is heparin-induced thrombocytopenia (HIT)?
platelet destruction post heparin therapy due to antibody formation
Why does heparin cause HIT?
Heparin can form complexes with platelet factor 4, and an IgG autoantibody can develop against this, leading to destruction in the spleen
What is the major complication of HIT and how does it work?
thrombosis due to platelet fragments activating other platelets
What is the treatment of HIT?
stop Heparin and give anticoagulant, but NOT COUMADIN
What is DIC?
pathologic (abnormal)activation of the coagulation cascade (as opposed to physiologic)
What is the result of DIC?
widespread microthrombi –> ischemia, infarction; also consumption of platelets and factors –> bleeding
Where will DIC pts bleed from?
IV sites, mucosal surfaces
DIC is almost always 2a to another disease process, such as _____, _____, _____, _____, and _____.
- obstetric complications
- sepsis
- adenocarcinoma
- APL
- rattlesnake bite
How do obstetric complications lead to DIC?
amniotic fluid contains a lot of tissue thromboplastin (TT), which is a strong activator of the coagulation cascade
How does sepsis lead to DIC?
- bacterial endotoxin can activate coag. cascade
2. cytokines produced by macs can activate coag. cascade
How does adenocarcinoma lead to DIC?
mucin produced by the adenocarcinoma can activate coag. cascade
How does APL lead to DIC?
Auer rods/primary granules activate coag cascade in circulation
How does a rattlesnake bite lead to DIC?
venom in circulation activates the coag cascade
What lab findings will be seen in DIC?
- decreased platelet count
- increased PT
- increased PTT
- decreased fibrinogen
microangiopathic hemolytic anemia (schistocytes) - elevated fibrin split products (D-dimer)*** best test
What is the product of lysing cross-linked fibrin?
D-dimer
What is the tx for DIC?
address underlying cause, then transfuse or give cryoprecipitate
What is fibrinolysis?
the removal of a thrombus
What is plasmin?
a molecule that stops clotting and removes clots
What does tPA do?
it converts plasminogen into plasmin
What does plasmin do?
- cleaves fibrin
- cleaves serum fibrinogen and clotting factors
- blocks platelet aggregation
What would overactive plasmin result in?
little to no blood clotting- a disorder of fibrinolysis
What is alpha-2-antiplasmin?
molecule that inactivates plasmin
How does radical prostatectomy cause overactive plasmin?
the procedure releases urokinase, which activates plasmin
How does liver cirrhosis cause overactive plasmin?
causes reduced production of alpha2-antiplasmin, allowing increased plasmin
How do the disorders of fibrinolysis present?
resembling DIC
What are the lab findings in the disorders of fibrinolysis?
- increased PT
- increased PTT
- increased bleeding me
- normal platelet count
- increased fibrinogen split products WITHOUT D-dimer
What is the tx for a disorder of fibrinolysis?
aminocaproic acid
How does aminocaproic acid work?
it bocks the activation of plasminogen
Where is alpha2-antiplasmin produced?
in the liver