Hematology - Clinical Flashcards
What are four important coagulation lab studies?
- Prothrombin time (PT)
- International Normalized Ration (INR)
- Partial Thromboplastin Time (PTT)
- Platelet count
What does TTP stand for?
Explain the disorder…
Thrombotic thrombocytopenia purpura
Rare disorder where formation of tiny blood clots “eat” platelets only.
What abnormalities could TTP present with?
Renal and neurological abnormalities
What does ITP stand for?
Explain the disorder…
Idiopathic thrombocytopenia purpura
Platelets get coated with IgG → not recognized as “self”
↓ ↓
Macrophages destroy platelets
What does DIC stand for?
Explain the disorder…
Disseminated intravascular coagulation
Multiple little clots created throughout vasculature
↓ ↓
Blood clots “eat” clotting factors AND platelets
↓ ↓
Bleeding
ITP is usually what kind of disorder?
Autoimmune
Which thrombocytopenic disorder is a common pathological activation of clotting cascade?
a) Thrombotic thrombocytopenic purpura (TTP)
b) Idiopathic thrombocytopenic purpura (ITP)
c) Disseminated intravascular coagulation (DIC)
c) Disseminated intravascular coagulation (DIC)
What is the main difference between TTP and DIC?
TTP → “eat” platelets only
DIC → “eat” clotting factors and platelets
What is a complex disorder of simultaneous hemorrhage and clotting?
DIC
Steps in DIC:
What happens when abnormally high amounts of activated thrombin are produced?
Thrombin does not remain localized
Steps in DIC:
What happens when there is an unregulated release of thrombin?
Widespread fibrin formation
Steps in DIC:
What happens when there is accelerated fibrinolysis?
Widespread thromboses
DIC can cause what three types of widespread conditions?
- Ischemia
- Infarction
- Organ hypoperfusion
T or F:
DIC has a low mortality rate.
False
(It has a high mortality rate.)
The treatment for DIC is to remove what?
Stimulus (if possible)
What are four different signs and symptoms for DIC?
- Bleeding from venipuncture sites
- Bleeding from arterial lines
- Purpura, petechiae, and hematomas
- Symmetric cyanosis of the fingers and toes
What are three hereditary bleeding disorders?
- Hemophillia A
- Hemophillia B
- Von Willebrand’s Disease
What clotting factor is deficient in Hemophillia A?
Factor VIII
What clotting factor is deficient in Hemophillia B?
Factor IX deficient (Christmas)
What is deficient in Von Willebrand’s Disease?
vWF
What are two thromboembolic disorders?
- Thrombi
- Emboli
What are three bleeding disorders treated wth clotting factors?
- Hemophilia
- Liver disease
- Bone marrow disorders
What is hemophilia?
What is a patient with hemophilia vulnerable to?
- Genetic deficiency of clotting factors
- Patient vulnerable to excessive bleeding from minor trauma
Why are patients with liver disease treated with clotting factors and proteins?
They are not being produced by the liver.
Why are patients with bone marrow disorders treated with clotting factors?
There is an insufficiency of platelet production in bone marrow.
Von Willebrand’s Disease also occurs in who else (other than humans)?
T or F:
Von Willebrand’s Disease is inherited.
False
(It may be inherited or acquired.)
T or F:
Von Willebrand’s Disease doesn’t always require treatment.
True
What happens to Factor VIII when there is an insufficient amount of vWF?
What does this now cause?
- Since Factor VIII cannot bind to vWF, it rapidly degrades.
- If there is insufficient Factor VIII → bleeding
What are eight risk factors for blood clotting?
- Prolonged bed rest
- Prolonged immobility
- Phlebitis
- Pregnancy
- History of previous embolus
- Genetic disorders
- Surgery (especially pelvic)
- Malignancy
What are four drugs for coagulation disorders?
- Anticoagulants
- Antiplatelet Agents
- Thrombolytics
- Hemostatics
How do anticoagulants work?
How do they accomplish this?
- Prevent clot formation
- Either directly or indirectly inhibit thrombin formation
T or F:
Anticoagulants do not dissolve existing clots.
True
By inhibiting thrombin formation in clotting cascade, what do anticoagulants prevent?
- Formation of new clot
- Enlargement of existing blood clot
T or F:
While patients are taking anticoagulants, monitoring labs are required throughout therapy.
True
Antiplatelet agents interfere with _________ _________which then alters the formation of __________ _________.
Platelet function; platelet plug
T or F:
Thrombolytics do not dissolve exisiting clots.
False
(Thrombolytics do dissolve exisitng blood clot)
What do thrombolytics stimulate in order to break down an exisiting thrombus?
Plasmin system
How do hemostatics work?
They promote formation of blood clot.
What is the main difference between anticoagulants and thrombolytics?
Anticoagulants → Inhibits thrombin formation but cannot break down.
Thrombolytics → Dissolve existing blood clot.
What two tests evaluate efficacy of extrinsic pathway?
- PT
- INR
What test evaluates efficacy of both intrinsic and common pathways?
PTT (aka aPTT)
What test is used to standardize PT results due to variations in manufacturer’s TF?
INR
What are the three steps in measuring PT and INR?
- Measure patient’s PT (how long it takes for their blod to clot following injury)
- Apply PT/INR ratio formula to standardize the results with all labs everywhere
- Use the INR result to determine the patient’s clotting status
What are the three anticoagulants administered IV?
- Bivalirudin (Angiomax)
- Argatrobin
- Antithrombin (ATryn)
What are two anticoagulants admistered by Subq?
- Fondaparinux (Arixtra)
- Desirudin (Iprivask)
What are three anticoagulants administered by PO?
- Apixaban (Eliquis)
- Dabigatran etexilate (Pradaxa)
- Rivaroxaban (Xarelto)
What anticoagulant is used in conjunction with ASA (aspirin) to prevent clots during transluminal coronary angioplasty?
Bivalirudin (Angiomax)
IV
What anticoagulant is used to prevent thrombosis in heparin-induced thrombocytopenia (HIT)?
Argatroban
IV
What anticoagulant is used to prevent thrombosis for peri-op / peri-partum in hereditary antithrombin deficiency?
Antithrombin (ATryn)
IV
What are the three anticoagulant prototypes?
- Warfarin (Coumadin)
- UF Heparin (Heparin Sodium)
- LMW Heparin → Enoxaparin (Lovenox)
What is the MOA for Coumadin?
Interferes with hepatic synthesis of vitamin K-dependent clotting factors.
What are the four indications for Coumadin?
Long-term OP management of anticoagulation
- Atrial Fibrillation
- Prosthetic heart valve
- Post CVA (Cerebrovascular Accident → Stroke)
- Post PE (Pulmonary Embolism)
What route(s) can Coumadin be administered by?
PO and IV
What is the start dose for Coumadin?
2-5 mg/d X 2-4 d;
adjust according to INR
Where is Coumadin metabolized?
Liver
How is Coumadin excreted?
Renal
What test(s) do you use to monitor a patient on Coumadin?
PT and INR
(goal of 2-3 x normal)
What are six precautions to consider before administering Coumadin?
- Surgeries
- Dental work
- GI bleed - especially in elderly
- Contraindicated in pregnancy
- Food / supplements high in Vitamin K
- MULTPILE drug/drug interactions
If you give Coumadin to a pregnant lady, what could happen to the baby?
- Hypoplastic distal phalanges
- Cleft palate
- Small nails
- Flat nasal bridge
What are six adverse reactions of Coumadin?
- Hemorrhage
- Diarrhea
- Urticaria
- Alopecia
- Tissue necrosis
- Dermatitis
How many formulations of Heparin are there? What are they?
Two
- Unfractioned
- Fractioned
True or False:
Fractioned Heparin has high molecular weight.
False
(Fractioned is low molecular weight (LMW) and Unfractioned is high molecular weight)
What is the MOA for both UF and LMW Heparin?
Binds to Antithrombin III
↓ ↓
Inhibits conversion (by thrombin) of fibrinogen to fibrin.
What route(s) can UF Heparin (Heparin Sodium) be administered by?
IV and Subq
What is the usual dose of UF Heparin (Heparin Sodium)?
- 15,000 - 20,000 units bid (IV)
- 5,000 - 40,000 / d (Subq)
How is UF Heparin (Heparin Sodium) metabolized?
Liver
How is UF Heparin (Heparin Sodium) excreted?
Renal