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Hematology - Coagulation Disorders


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How does Thrombocytopenia present?
1) Petechiae
2) Epistaxis
3) CNS bleeds
4) GI bleeds
Bleeding Time is elevated at PL counts less than _____.
Clinically significant bleeds start at PL counts less than _____.
CNS bleeds occur with PL counts less than _____.
What are some causes of Thrombocytopenia?
1) Stem cell failure (leukemia, aplastic anemia, alcohol, PNH)
2) Increased platelet destruction
3) Splenic sequestration
What is Idiopathic Thrombocytopenic Purpura (ITP)?
Autoimmune/autoantibody-mediated PLATELET DESTRUCTION! In kids, follows URI and self-limited. In adults, chronic.
What are si/sx of Idiopathic Thrombocytopenic Purpura?
1) Petechiae
2) Purpura
3) Epistaxis
*normal RBC & WBC morphology
How do you Tx ITP?
1st Steroids
2nd Splenectomy
3rd Immunosuppressives (AZT, cyclophosphamide)
What is the classic pentad of Thrombotic Thrombocytopenic Purpura (TTP)?
1) Intravascular hemolytic anemia
2) Renal failure (proteinuria, hematuria, inc. creatinine)
3) Thrombocytopenia
4) Neurologic changes
5) Fever
How do you Tx TTP?
Plasma exchange, or IV immunoglobulin until disease abates.
Which drugs can induce Thrombocytopenia? (reversible upon stopping drug)
1) Heparin
2) Sulfonamides
3) Sulfonylureas
4) Valproic acid
5) Fever Few
6) Abciximab
7) Aspirin
Which bacteria can cause Hemolytic Uremic Syndrome in children?
E. coli O157:H7
What are si/sx of HUS?
1) Glomerulosclerosis --> ARF
2) Bloody diarrhea, abdominal pain, seizures
3) Fulminant thrombocytopenia with hemolytic anemia
What is Tx for HUS?
What do the RBC's look like in TTP?
Schistocytes (fragmented cells)
How does Evan's Syndrome cause Platelet destruction?
IgG autoantibodies --> hemolytic anemia & thrombocytopenia (sometimes pancytopenia)
What other diseases are associated with Evan's Syndrome?
1) TTP
2) Collagen-vascular disease
3) Hashimoto's thyroiditis
4) Leukemia
5) Sarcoidosis
How do lymphomas and leukemias cause platelet destruction?
Antiplatelet antibodies, induce splenic sequestration.
How does DIC cause platelet destruction?
Platelets are trapped in fibrin mesh deposited within vessels.
What are some causes of splenic sequestration of platelets (leading to thrombocytopenia)?
1) Portal HTN
2) Lymphoma
3) Leukemia
4) Massive infection
5) Chronic inflammation
Autoantibody-Induced Platelet Destruction:
blood smear = _____
Coomb's test = _____
PT/PTT = _____
blood smear = _____
Coomb's test = _____
PT/PTT = _____
blood smear = _____
Coomb's test = _____
PT/PTT = _____
normal/slightly elevated
What is the most common inherited bleeding disorder?
von Willebrand Factor deficiency, most commonly Auto Dominant
vWF is secreted by _____ cells, binds to GP_____, bridging Platelet to _____.
endothelial cells; GP1b; subendothelial matrix
How do you Dx vWF deficiency?
1) vWF levels
2) Ristocetin-cofactor test (meas. PL aggregation induced by ristocetin binding of vWF)
bleeding time = _____
PT/PTT = _____
increased bleeding time
normal PT/PTT
How do you Tx vWF deficiency?
1) DDAVP (inc. vWF secretion-only for Type 1)
2) Cryoprecipitate (contains factors VIII, IX, vWF, fibrinogen)
What is Bernard-Soulier syndrome?
1) Auto Recessive
2) defect GPIb platelet receptor that binds vWF
3) can't aggregate platelets
How does Bernard-Soulier syndrome present?
Chronic severe mucosal bleeds & giant platelets on smear
How do you Tx Bernard-Soulier syndrome?
platelet transfusion
What is Glanzmann's Thrombasthenia?
1) Auto Recessive
2) defect GPIIb/IIIa receptor platelet receptor that binds fibrinogen
How does Glanzmann Thrombasthenia present, and how do you Tx?
chronic mucosal bleeds; platelet transfusion
What is deficient in Hemophilia A?
X-linked factor VIII deficiency
How does Hemophilia A present?
Hemarthroses (bleed into joints) and easy bruising
Hemophilia A:
bleeding time = _____
PTT = _____
PT = _____
How do you Tx Hemophilia A?
Recombinant factor VIII, cryoprecipitate
Can have acquired factor VIII deficiency due to circulating antifactor VIII antibody -- differentiate from genetic by:
Add patient's serum to control serum. If have antibody, PTT of mixed serum will be prolonged. If genetic deficiency, normal PTT.
What is missing in Hemophilia B (Christmas Disease)?
X-linked factor IX deficiency
How do you Tx Hemophilia B?
factor IX concentrate
The _____ makes all clotting factors.
Vitamin K is a necessary cofactor for the enzyme ______ which activates factors: ______ so they can interact with _____.
gamma-carboxylase; II, VII, IX, X, proteins C & S; calcium.
Thrombin activates _____, which combines with cofactor _____ to inactivates factors: _____ & _____.
Protein C
Protein S
Va & VIIIa
Liver disease and Vit K deficiency:
PT = _____
PTT = _____
much increased
Initial Coumadin administration can cause:
fulminant skin necrosis secondary to capillary thrombosis (b/c Coumadin also interferes with Protein C synthesis)
What is the most common inherited HYPERcoagulable disease?
Factor V Leiden disease, a.a. substitution makes it resistant to cleavage by Protein C --> dysregulated coagulation and high risk DVT and PE
This congenital hypercoagulable disease is a deficiency in something whose action is enhanced by heparin.
Antithrombin III, supposed to inhibit Thrombin and factor Xa
Congenital deficiency in _____ & _____, which cleave factors V and VIII, lead to uninhibited coagulation.
Protein C & S
What are some acquired/secondary causes of hypercoagulable states?
1) prolonged immobilization
2) pregnancy
3) OCP's
4) smoking
5) diabetes mellitus
6) DIC

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