Other disorders of hemostasis Flashcards
heparin induced thrombocytopenia pathophys
heparin forms a complex with platelet factor 4, leading to formation of igG antibodies and consumption of platelets
DIC pathophys
- widespread microthrombi lead to ischemia and infarction
- consumption of platelets and factors leads to bleeding
What disease processes may DIC occur secondarily to…
Obstetrics complications -tissue thromboplastin activates coagulation
Sepsis – endotoxins/cytokines induce Tissue factor
Adenocarcinoma - mucin activates coagulation
Acute promyelocytic leukemia -primary granules activate coagulation
Rattlesnake bite -venom activates coagulation
Lab findings in DIC
Decreased platelet count Decreased fibrinogen Increased PT/PTT Microangiopathic hemolytic anemia Elevated fibrin split products -D Dimer
Treatment of DIC
Treat underlying cause
Blood transfusion and cryoprecipitate as needed
alpha-2 antiplasmin function
inactivates plasmin
tPA function
activates plasminogen to plasmin
What are the two disorders of fibrinolysis?
Radial prostateectomy – release of urokinase activates plasmin
Cirrhosis of liver – reduced production of alpha-2 antiplasmin
presentation and lab findings of disorders of fibrinolysis
plasmin overactivity –> increased bleeding time
Increased PT/PTT
Increased bleeding time with normal platelets
Increased fibrinogen split products with absent D-Dimers(no fibrin thrombi present)
treatment of disorders of fibronolysis
aminocaproic acid (blocks activation of plasminogen)
how to distinguish thrombus from post mortem clot?
lines of zahn (alternating platelets/fibrin and RBC layers) and attachment to blood vessel wall
virchows triad
blood flow disruption, endothelial damage, hypercoaguable state
Lack of B12 or folate results in build up of what?
homocysteine
Homocysteine causes waht
endothelial damage
What is cystathionine beta synthase deficiency
Cause of high homocysteine with homocystinuria
CBS usually converts homocysteine to cystathione
Characterized by vessel thrombosis, mental retardation, lens dislocation and long fingers
What is factor V leiden?
A mutated form of factor V that lacks the cleavage site for deactivation by protein C and S
What is prothrombin 20210A?
An inherited point mutation in prothrombin that results in increased gene expression
What is ATIII deficiency and what will happen with heparin dosages?
ATIII usually inactivates thrombin and coag factors, thus with a deficiency PTT does not rise with standard heparin dosing
Must give high dose of heparin then switch to Coumadin
How does estrogen effect coagulation?
Increases production of coag factors
Atherosclerotic embolus histology
Will have cholesterol clefts
Fat embolus histology
fat with bone marrow elements
What is the cause of a gas embolus?
Usually from rapid ascent of a diver, as nitrogen gas precipitates out of blood, leading to the bends
Symptoms of the ‘bends’
Joint, muscle pain. Respiratory symptoms
Amniotic fluid embolus presentation
DIC, SOB, neurological symptoms
Amniotic fluid embolism histology
squamous cells and keratin debris in embolus from fetal skin
Death from PE is caused by what?
electromechanical dissociation in heart
