Approach to the Bleeding Patient Flashcards
How do you calculate INR?
PT (patient) divided by PT (mean normal)
Raised to exponent (ISI)
PT=prothrombin time
What are 5 ways liver disease affects clotting?
Vitamin K deficiency Thrombocytopenia Decreased production of clotting factors Dysfibrinogenemia Increased fibrinolytic activity
What are the results of inappropriate thrombin generation in DIC?
- thrombocytopenia
- drop in fibrinogen
- decrease in factors (particularly V/VIII)
- Low levels of antithrombin III and Protein C
- Secondary fibrinolysis
Causes of DIC?
Infection
Malignancy
Obstetric complications
Treatment of DIC
- Identify and treat the underlying cause
- Fresh frozen plasma
- Platelets
- Antithrombin III concentrates
- Activated protein C concentrates
What are 5 symptoms of Thrombotic thrombocytopenic Purpura (TTP)?
- Microangiopathic hemolytic anemia
- Thrombocytopenia
- Mental status changes
- Renal insufficiency
- Fever
What are 6 diagnostic indicators of TTP?
- Schizocytes on PBS
- Thrombocytopenia
- Markedly elevated LDH
- Increased indirect bilirubin
- Decreased ADAMTS13
- Antibody to ADAMTS13
Treatment of TTP?
Plasma exchange
Fresh frozen plasma
Steroids
Rituximab
Do NOT treat TTP with:
platelets
Differential diagnosis of microangiopathic hemolytic anemia and thrombocytopenia?
TTP Hemolytic uremic syndrome (HUS) HELLP syndrome DIC SLE Malignant hypertension
If there is a low platelet count + bleeding, what are the 3 lab tests you are going to order?
- BM examination (production prob)
- Platelet Abs (ITP)
- Screening test for DIC
If there is a normal platelet count + bleeding, what are the 4 tests you want to order?
- PT and PTT (clotting factors)
- Platelet aggregation studies with ADP, epi, collagen
- Other platelet tests (adhesion molecules)
- 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
T
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?
2-2.5
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?
fibrinogen PTT PT platelet count factor 5 and 8 anti-thrombin 3 protein C fibrinolysis
fibrinogen: low PTT: high PT: high platelet count: low factor 5 and 8: low anti-thrombin 3: low protein C: low fibrinolysis: high
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
T
What treatment for DIC directly blocks the action of thrombin?
anti-thrombin 3 concentrate
Who is most likely to get TTP?
women 20-40s
What are the 3 signs/symp of TTP?
MAHA
thrombocytopenia
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
Why do you not give a TTP pt platelets?
they will cause them to stroke
