Flashcards in Approach to the Bleeding Patient Deck (31):
How do you calculate INR?
PT (patient) divided by PT (mean normal)
Raised to exponent (ISI)
What are 5 ways liver disease affects clotting?
Vitamin K deficiency
Decreased production of clotting factors
Increased fibrinolytic activity
What are the results of inappropriate thrombin generation in DIC?
2. drop in fibrinogen
3. decrease in factors (particularly V/VIII)
4. Low levels of antithrombin III and Protein C
5. Secondary fibrinolysis
Causes of DIC?
Treatment of DIC
1. Identify and treat the underlying cause
2. Fresh frozen plasma
4. Antithrombin III concentrates
5. Activated protein C concentrates
What are 5 symptoms of Thrombotic thrombocytopenic Purpura (TTP)?
1. Microangiopathic hemolytic anemia
3. Mental status changes
4. Renal insufficiency
What are 6 diagnostic indicators of TTP?
1. Schizocytes on PBS
3. Markedly elevated LDH
4. Increased indirect bilirubin
5. Decreased ADAMTS13
6. Antibody to ADAMTS13
Treatment of TTP?
Fresh frozen plasma
Do NOT treat TTP with:
Differential diagnosis of microangiopathic hemolytic anemia and thrombocytopenia?
Hemolytic uremic syndrome (HUS)
If there is a low platelet count + bleeding, what are the 3 lab tests you are going to order?
1. BM examination (production prob)
2. Platelet Abs (ITP)
3. Screening test for DIC
If there is a normal platelet count + bleeding, what are the 4 tests you want to order?
1. PT and PTT (clotting factors)
2. Platelet aggregation studies with ADP, epi, collagen
3. Other platelet tests (adhesion molecules)
4. vWF and Factor VIII assays
What lab test distinguishes between vWF disease and hemophilia?
vWF assay: both will have low Factor 8 but vWF disease will also have low vWF
What is a correction/inhibitors test? Explain the results
pt plasma mixed with normal plasma and do a PPT
normal PPT= could be factor deficiency
abnormal PPT = patient has an inhibitor (Ab against a factor)
T of F: Aspirin will affect a platelet function analysis
What can cause a long platelet function analysis performed with epi and ADP?
vWF disease or platelet dysfunction
What test do you perform to check if anti-platelet drugs are working?
platelet aggregation study
What is the therapeutic range for INR?
Why do we use INRs?
A way to compare bleeding across all labs
(human brain vs rabbit brain used for thromboplastin)
What is the definition of disseminated Intravascular Coagulation?
inappropriate generation of thrombin
For a pt with DIC will the following be normal, low, or high?
factor 5 and 8
platelet count: low
factor 5 and 8: low
anti-thrombin 3: low
protein C: low
Why do you see peripheral gangrene in DIC?
clotting off capillaries
T or F: in DIC, pt can bleed and get thrombosis at the same time
What treatment for DIC directly blocks the action of thrombin?
anti-thrombin 3 concentrate
Who is most likely to get TTP?
What are the 3 signs/symp of TTP?
mental status changes (TIA, stroke, headache, irritable)
What is the pathogenesis of TTP?
Ab to ADAMTS13 = vWF multimer does not get cleaved--> causes platelet aggregates in microcirculation --> RBCs try to get past them and are fragmented (schistiocytes formed) --> more and more capillary beds are involved
What is the function of ADAMTS31?
protease that cleaves vWF multimers to be the correct size
T or F: the presnece of the ADAMTS31 Ab is the lab value you need to confirm Dx and begin Tx.
F: if you wait until you get the Ab results the pt will be dead
What is the most effective Tx for TTP?
plasma exchange + immunosupressants bc 40% will relapse