1. Obtain a complete history.
2. In a patient presenting with a bleeding or clotting disorder, an initial evaluation should include bleeding time, prothrombin time (PT), activated partial throm-boplastin time (aPTT), thrombin time, and platelet count.
• Activated partial thromboplastin time: aPTT is performed by adding calcium phospholipids and kaolin to citrated blood and measures the time required for a fibrin clot to form. In this manner, aPTT measures the activity of intrinsic and common pathways. Prolongation of aPTT may be due to a deficiency or inhibitor for factors II, V, VIII, IX, X, XI, and XII. It also may be due to heparin, direct thrombin inhibitors, vitamin K deficiency, liver disease, or lupus anticoagulant.
• Prothrombin time: PT is performed by adding thromboplastin (tissue) factor and calcium to citrate-anticoagulated plasma, recalcifying the plasma, and measuring the clotting time. The major utility of PT is to measure the activity of the vitamin K-dependent factors II, VII, and X. The PT is used in evaluation of liver disease, to monitor warfarin anticoagulant effect, and to assess vitamin K deficiency.
• Thrombin time is an assessment of the time required for the appearance of the fibrin clot after thrombin is added to plasma. It may be affected by thrombin inhibitors or fibrinogen abnormalities. Most commonly, thrombin time is used to monitor fibrinolytic therapy.
• Bleeding time indicates how well platelets interact with blood vessel walls to form blood clots by assessing the length of time to arrest the bleeding after a standardized skin cut. The bleeding time is prolonged in thrombocytopenia, fibrinogen disorders, and collagen defects.
3. After a diagnosis is made, institute specific therapy.
4. Monitor resolution of laboratory and clinical symptoms with treatment.
TTP that fails to respond adequately to PEX can be treated with immunosuppressive agents. Cytotoxic immunosuppressive therapies with potential benefit in refractory TTP include vincristine, cyclophosphamide, azathioprine, rituximab, and the CHOP
combination regimen (cyclophosphamide, doxorubicin, vincristine, and pred-33
Monitor platelet counts, hemoglobin, and LDH.
Abbreviations Introduced in This Chapter
ADAMTS13 A disintegrin and metalloprptease with
DDAVP l-Desamino-8-D-arginine vasopressin
DIC Disseminated intravascular coagulation
ITP Immune thrombocytopenic purpura
IVig Intravenous immunoglobulin
PCC Prothrombin complex concentrate
RICD Recessively inherited coagulation disorders
TT I1 Th rombotic th rombo cy t open ic p urpur a wwvit
^ Self-assessment questions and answers are available at ht-tp://www. mhpharmacotherapy. com/pp.html.
Was this article helpful?
Do You Suffer From ASTHMA Chronic asthma is a paralyzing, suffocating and socially isolating condition that can cause anxiety that can trigger even more attacks. Before you know it you are caught in a vicious cycle Put an end to the dependence on inhalers, buying expensive prescription drugs and avoidance of allergenic situations and animals. Get control of your life again and Deal With Asthma Naturally