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What is the TTP classis Pentad? Transient Neuro Prob, Fever, Thrombocytopenia, Microangiopathic Hemolytic Anemia, Acute Renal Failure
Hemorrhagic diatheses may be caused by... increased blood vessel fragility, platelet disorders, coagulation defects, or some type of combination of these
What values are used to evaluate bleeding diatheses?# Bleeding Time, Platelet count, Prothrombin Time, Partial Thromboplastin Time
What is BT? Bleeding Time–plat response to vascular injury,
What is Platelet Count? Plat. Count–< 100K = thrombocytopenia,20K – 50K =post-traumatic bleeding,spont bleeding at < 20K,
What is PT? Prothrombin Time –adequacy of Extrinsic/common pathways. Inc PT -> def of V, VII, X, prothrombin, or fibrinogen.
What is PTT? Partial Thromboplastin Time– integrity Intrinsic/common clotting pathways. Prolongation of PTT may be due to a deficiency of factor V, VIII, IX, X, XI, or XII or of prothrombin or fibrinogen
What are clinical char most closely associated with platelet defects? Site of bleeding is skin, mucous membrane etc. Bleeding after minor cuts, Petechiae, small superficial ecchymoses, mild and immediate bleeding after surgery
What are clinical char most closely associated with clotting factor disorder? Bleeding in deep soft tissues (joints and muscles), large, palpable ecchymoses, common hemarthroses and muscle hematomas, delayed and severe bleeding associated with surgery
What are the causes of thrombocytopenia that can be classified into 5 major categories? Decreased Production, Decreased Survival, Sequestration,Dilution, HIV.
What is dec production refer to in thrombocytopenia? Thrombocytopenia is due to ineffective megakaryopoiesis or to generalized marrow disease that also compromises megakaryocyte number (aplastic anemia)
What is dec survival refer to in thrombocytopenia? Thrombocytopenia due to immune mediated platelet destruction which can follow drug exposure (quinine, quinidine, methyldopa, heparin), or infections (HIV). Platelet deficiencies due to consumption often occur in systemic coagulopathies (DIC, HUS, or TTP)
What is sequestration refer to in thrombocytopenia? Sequestration: Platelets may be retained in the red pulp of enlarged spleens
What is dilution refer to in thrombocytopenia? Massive whole blood transfusions can cause a relative reduction in the number of circulating platelets.
How does HIV contribute to thrombocytopenia? Thrombocytopenia results from immune complex injury, antiplatelet antibodies, and HIV-induced suppression of megakaryocytes.
Immune thrombocytopenic purpura (ITP) is a clinical syndrome in which... a decreased number of circulating platelets (thrombocytopenia) manifests as a bleeding tendency, easy bruising (purpura), or extravasation of blood from capillaries into skin and mucous membranes (petechiae).
In children, immune thrombocytopenic purpura (ITP) is more common among ___. In middle-aged adults, _____are affected more freq. boys,women
Describe Acute ITP. Self-limited disorder that is most often seen in children after a viral infection (rubella, CMV, Viral hepatitis, Infectious Mononucleosis). The platelet destruction is due to transient antiplatelet autoantibodies.
Describe the pathophysiology of ITP? abnormal autoAb, usually IgG w/ specific for 1 or more platelet membrane glycoproteins, binds to circulating platelet inducing phago. by macros in spleen. Impaired thrombopoiesis from failure of comp. inc. in thrombopoietin and megakaryocyte apoptosis.
Describe Chronic ITP. Chronic ITP – Platelet autoantibodies that are synthesized in the spleen are directed toward one or two platelet antigens on the platelet membrane glycoprotein complexes GPIIb/IIIa or Ib/IX. A splenectomy benefits 75 – 80% of these patients
What is the morphology of the spleen in ITP? The spleen is normal in size but shows sinusoidal congestion and prominent germinal centers. (Bone marrow megakaryoctye numbers are increased)
Describe diagnosis of ITP. Largely based on clinical features, such as petechiae and thrombocytopenia seen on CBC. BT is Prolonged, while the PT and PTT are normal. Bone Marrow Biopsy will show increased megakaryoctye numbers
What is the tx for ITP? Most children w/acute ITP do not req tx, and thrombocytopenia resolves spontaneously. Corticosteroids (ie, oral prednisone, IV methylprednisolone) or high-dose dexamethasone are first choice in adults. IVIG) is drug of second choice for many years.
TTP-HUS is associated with what? thrombi composed primarily of platelets in affected organs
TTP is associated with inherited or acquired deficiencies in...? ADAMTS13, a serum metalloprotease that limits the size of von Willebrand factor multimers in the plasma.
Describe the pathophysiology of TTP. In absence of ADAMTS13, very high mw vWF multimers accumulate and promoting platelet aggregation throughout microcirculation. In the case of acquired TTP, patients often have antibodies directed against ADAMTS13. Acquired TTP typically affects women.
Describe the pathophysiology of HUS. commonly fol GI inf. w/ verotoxin-producing E. coli ->injures endo.cells and promotes dysregulated platelet activation/aggregation. Occurs in children/elderly in food poisoning. E. Coli O157: H7 causes severe, bloody diarrhea, abd cramps, kidney failure.
When acute renal failure is dominant and neurologic abnormalities are minimal or absent, the disorder is considered by some to represent... HUS.
If neurologic abnormalities are dominant and acute renal failure is minimal or not present; these patients are considered by some to represent ... idiopathic or "classical" TTP.
What are the mech for disorder related to defective platelet function? Defective platelet adhesion and defective platelt aggregation
Desrcibe Bernard-Soulier Syndrome. This is autosomal recessive disorder caused by a deficient platelet membrane glycoprotein complex GpIb/IX. This glycoprotein is a platelet receptor for vWF and is necessary for platelet-collagen adhesion.
Describe Glanzmann's Thrombasthenia. Aan autosomal recessive disorder caused by a deficiency of platelet membrane glycoprotein IIb-IIIa, the fibrinogen receptor. These glycoproteins in normal states promote platelet aggregation by forming fibrinogen bridges between adjacent platelets.
What are tTwo acquired disorders that are clinically significant for hemorrhagic disorders related to defective platelet function? Aspirin Ingestion and Uremia.
What are 5 main clotting factor abnormalities? von Willebrand Factor (vWF) Disease, Hemophilia A, Hemophilia B, Disseminated Intravascular Coagulation (DIC), and Vitamin K deficiency.
What is Von Willebrand disease (VWD)? most common inherited bleeding disorder, affects 1 percent of pop,<5 percent aresymptomatic. Characterized by mutations that inhibit synthesis/action of(VWF). Transmitted as an autosomal dominant trait, affects males and females equally.
Describe the Von Willebrand factor (VWF). Large multimeric glycoprotein that acts as a bridge for normal platelet adhesion and aggregation at sites of vascular injury under high shear conditions, and is factor VIII carrier in circ, increasing the half-life of factor VIII 5x
Describe Type 1, 2, and 3 VWD? 1 and 3 assoc.w/ reduced levels of vWF. 1:auto dominant, most common, mild. 2:auto dominant caused by reduced amts of intermediate and large vWF multimers (most active forms of vWF). 3:severe, uncommon auto recessive assoc. w/ profound vWF deficiency.
What are the clinical features of VWD? low incidence of bleeding, factor VIII reduced because vWF stabilizes factor VIII in circ., Most commonly presents w/ spontaneous bleeding from mucous membranes, (orophayngeal, GI, and uterine) excessive bleeding from wounds, and menorrhagia.
What lab values are indicative of VWD? compound defect involving platelet function and coagulation pathway is reflected by a prolonged bleeding time (despite normal platelet counts) and a prolonged PTT, may have a prolonged aPTT due to a mild to moderate concordant deficiency of factor VIII.
Useful tests for VWD include... bioassay of factor VIII, immunoassay of VWF antigen, and measurement of ristocetin cofactor activity.
What is the treatment for VWD? Desmopressin which promotes the release of VWF from endothelial cell storage sites.
Hemophilia A is ... X-linked recessive disorder primarily affecting males. It is characterized by a reduced amount and activity of factor VIII.
Clinical Features of hemophilia A is associated with the following: Massive hemorrhage fol trauma or op, Spontaneous hemorrhages in regions of body normally subj to trauma like joints (hemarthroses), may lead to crippling deformities. No petechiae. Prolonged PTT and normal bleeding time
How is Hemophilia A diagnosed? Hemophilia A diagnosis is possible by assay for factor VIII and can now be diagnosed antenatally by the cloning of the factor VIII gene.
Hemophilia B is ... an X-linked recessive disease caused by factor IX deficiency. It is clinically indistinguishable from hemophilia A. It is the least common form of haemophilia, rarer than haemophilia A. It is sometimes called Christmas disease
How is Hemophilia B diagnosed? Its diagnosis requires assay of factor IX levels.
How is Hemo A and B treated? hemophilia A involves infusion of VIII (note: some develop antibodies against VIII, they are thus heat treated);hemophilia B is by intravenous infusion of factor IX. Factor IX has a longer half life than factor VIII and can be transfused less frequently.
DIC is ... a sys. process producing thrombosis and hemorrhage, char by widespread clotting w/consumption of factors II, V, VIII, and fibrinogen. Develops when blood exposed to large amts of factor (VII of ext pathway)-inc thrombin -> acute triggering of coag.
DIC patients will ______while displaying ___________ hemorrhage,microthrombi
Causes of DIC are... release of tissue thromboplastin or activation of int pathway, or sec activation of fibrinolytic system, exposure to procoagulants from infection ,cancer, formation of fibrin w/in circ, fibrinolysis, depletion of clotting factors, and end organ damage.
DIC is seen most commonly in ... ob complications (toxemia, amniotic fluid emboli, dead fetus, abruption placentae); cancer (lung, pancreas, prostate, or stomach); infection (gram - sepsis, osteomyelitis); Trauma or immuno mech like immune complex disease or hemolytic transfusion rxn
What suggests the diagnosis of DIC? history (eg, sepsis, trauma, malignancy), clinical presentation, moderate to severe thrombocytopenia (<100,000/microL) and the presence of microangiopathic hemolytic anemia with fragmented (shistocytes).
Patients with DIC many times present with ... diffuse petechiae and ecchymoses w/ blood oozing from wound sites, intravenous lines, catheters, and,mucosal surfaces. Acute renal failure sometimes. Jaundice is common. Neuro abnormalities. Pulmonary hemorrhage with hemoptysis and dyspnea may result.
The diagnosis of DIC is confirmed by ... both inc thrombin (dec fibrinogen) and inc fibrinolysis (eg, elev FDPs and D-dimers). Expect prolonged BT, PT, PTT, Thrombin time, and inc fibrin and fibrinogen degradation (split) products. Fibrinogen levels trend downward, thrombocytopenia may occur.
How do you treat DIC? Tx w/ plat. and coag factors in pts w/ serious bleeding, inc bleeding risk, or req. invasive proc. Thrombocytopenia (<50,000/uL) and serious bleeding-> plat. transf.Elev INR and/or a fibrinogen conc <50 mg/dL-> FFP or cryoprec. to fibrinogen level>100.
Should administration of heparin or antithrombin be given to DIC pt? limited to subset of pts with chronic, compensated DIC who have predominantly thrombotic manifestations. It is important to be sure that pt's (AT) level is near normal (ie, 80 to 100 percent) so heparin may be effective
Vitamin K deficiency leads to... decreased activity of clotting factors II, VII, IX, and X and is reflected by prolongation of PT and PTT.
Vitamin K is essential for ... activation of coagulation factors and prothrombin.
What is the tx for vit K deficiency? Depending upon the cause of deficiency, vitamin K can be administered in doses of one to 25 mg via oral, intramuscular, subcutaneous, or intravenous routes.
Created by: jpop