Flashcards in Heme Emergencies 1 Deck (75)
All of procoagulants are synthesized in the liver except?
1. think which test?
2. Think which factors? 4
1. Think which test?
2. Think which factors? 2
1. Intrinsic pathway? Think PTT (partial thromboplastin time)
2. Think VIII, IX, XI, and XII
3. Extrinsic pathway? Think PT
4. Think II and VII
Note: **Both pathways converge on the activation of factor X, which subsequently results in prothrombin activator converting prothrombin into thrombin
Which factors are vit K dependant?
Factors VII, X, and prothrombin (Factor II) are vitamin-K dependent and are altered by warfarin (Coumadin) which is why we use the PT-INR to monitor warfarin therapy
The termination phase of the coagulation process involves two circulating enzyme inhibitors. What are these? 2
1) Antithrombin (formerly called antithrombin III)
2) Tissue factor pathway inhibitor
Clotting-initiated inhibitory process, the protein C pathway
Antithrombin does what? 2
1. activates coagulation factors and neutralizes thrombin (the last enzyme in the pathway for the conversion of fibrinogen to fibrin)
2. complexes with naturally occurring heparin to accelerate and provide protection against uncontrolled thrombus formation on endothelial surfaces.
1. What does Protein C do?
2. Protein s?
1. Protein C
A plasma protein
Acts as an anticoagulant protein by inactivating factors V and VIII
2. Protein S
A plasma protein
Breaks down fibrin into fibrin degradation products that act as anticoagulants
1. Plasminogen binds fibrin and tissue plasminogen activator (tPA)
2. Complex leads to conversion of the proenzyme plasminogen to active, proteolytic plasmin
3. Plasmin cleaves polymerized fibrin strand at multiple sites and releases fibrin degradation products including D-Dimer
1. Defects in Platelet number? 3
2. Defects in Platelet function? 1
3. Defects in the coagulation cascade? 4
1. Defects in Platelet number
-Thrombotic Thrombocytopenic Purpura
2. Defects in Platelet function
-Aspirin (drug-induced) platelet dysfunction
3. Defects in the Coagulation Cascade
-Hemophilia B (Christmas Disease)
-von Willebrands Disease
-Vitamin K deficiency
1. Normal platelet count?
1. Normal 100,000-400,000 cells/mm
2. less than 100,000 -Thrombocytopenia
3. 50,000-99,999 Mild
4. less than 50,000 Severe
Bleeding time normals?
PARTIAL THROMBOPLASTIN TIME
1. Measures what?
2. Normal value?
1. Measures Effectiveness of the Intrinsic
2. NORMAL VALUE
1. What is thrombin time?
3. Measure of what?
1. Time for Thrombin To Convert Fibrinogen to Fibrin Monomer
2. NORMAL VALUE
3. Measure of Fibrinolytic Pathway
Hemostasis is DEPENDENT UPON? 5
1. Vessel Wall Integrity
2. Adequate Numbers of Platelets
3. Proper Functioning Platelets
4. Adequate Levels of Clotting Factors
5. Proper Function of Fibrinolytic Pathway
What questions should I ask in the history if I suspect a bleeding abnormality?
1. Family History
3. Past Medical History
4. Previous Challenges to Hemostasis
Clinical Features of anemia? 5
3. Orthostatic Hypotension
4. Exertional Intolerance
PE for anemia? 5
1. Pale conjunctiva or skin
3. Systolic murmurs
4. Tachypnea at rest and
are late signs
1. Presence of what are diagnostic of anemia? 3
2. Determining the exact etiology of the anemia is not essential in the ED, except in when?
3. Initial eval should include ? 5
4. What are the initial studies needed in patients with suspected bleeding disorders?
-decreased RBC count,
2. the face of acute hemorrhage
-Review of RBC indices, and
-CBC with platelet count,
Disorders of Secondary Hemostasis
1. These are problems with what?
2. Intrinsic pathway? 3
3. Extrinsic? 1
1. Problem with the coagulation factors themselves
2. Instrinsic Pathway
3. Extrinsic Pathway
-Vitamin K deficiency
Approach to the thrombocytopenic patient
1. HX? 6
2. assess the number and function of platelets with what? 2
1. Is the patient bleeding?
2. Are there symptoms of a secondary illness? (neoplasm, infection, autoimmune disease)
3. Is there a history of medications, alcohol use, or recent transfusion?
4. Are there risk factors for HIV infection?
5. Is there a family history of thrombocytopenia?
6. Do the sites of bleeding suggest a platelet defect?
Assess the number and function of platelets
1. CBC with peripheral smear
2. Bleeding time or platelet aggregation study
Clinical manifestations: Hemophilia
(hemophilia A & B are indistinguishable)
1. Hemarthrosis (most common): Fixed joints
2. Soft tissue hematomas (e.g., muscle)
3. Muscle atrophy
4. Shortened tendons
Other sites of bleeding
5. Urinary tract
6. CNS, neck (may be life-threatening)
7. Prolonged bleeding after surgery or dental extractions
1. Swollen, painful joints
2. Local bleeding out of proportion to injury
3. Subcutaneous bleeding
4. Bleeding from mucous membranes
5. Abdominal pain, distension
6. Hematemesis, melena
1. Prolongation of what?
2. Hemophilia A deficiency in?
1. Prolongation of the aPTT (the PT will remain normal)
2. Hemophilia A (deficiency in factor VIII)
3. Hemophilia B (deficiency in factor IX) (Christmas Disease)
Hemo A etiology?
X-linked recessive pattern of inheritance
Describe the PP of Hemophilia A?
What is the kind of bleeding we are really worried about in these pts?
The blood of a person with hemophilia does not clot normally.
He does not bleed more profusely or more quickly than other people; however, he bleeds for a longer time.
External wounds are usually not serious.
Far more important is internal bleeding
These hemorrhages are in joints, especially knees, ankles and elbows; and into tissues and muscles
Signs and Symptoms
1. Petechiae and ecchymosis are characteristically absent.
2. Bleeding into joints- Knees, ankles, elbows
3. Bleeding into muscles- Spontaneous hemarthoses in severe disease
4. GI bleeding
5. Those with mild disease bleed after major trauma or surgery.
6. Those with moderately severe disease bleed with mild trauma or surgery.
7. Those with severe disease bleed spontaneously.
Lab findings? 5
1. PTT is prolonged
2. Factor VIII:C is reduced
3. vWF is normal
4. PT, Fibrinogen levels are normal.
5. Diagnosis is confirmed by decreased Factor VIII levels.
1. Avoid ASA
2. Factor VIII replacement: Recombinant Factor VIII concentrate
4. For mild hemophilia
**Can use EACA (Amicar) along with the above
2. Caused by?
3. How common?
4. Prolonged what?
5. Dx confirmed by?
1. Also called Christmas disease
2. X-linked bleeding disorder caused by deficiency of Factor IX.
3. Less common than hemophilia A.
4. PTT is prolonged.
5. Diagnosis is confirmed by demonstrating decreased Factor IX levels.
1. Avoid ASA
2. Factor IX concentrates
Factor VIII concentrates are INEFFECTIVE