platelet, hemostasis, and coagulation disorders Flashcards
(17 cards)
Stroke patient requires a “clot-buster”
tissue plasminogen activator (TPA)
Tissue plasminogen activator activates plasmin, a factor that degrades fibrin clots. Factor VIII is part of the clotting cascade, and thus increases clot formation.
Patient on anticoagulation therapy
PT range two to three times higher than normal
PT represents “prothrombin time,” which evaluates the extrinsic pathway of the clotting cascade. Anticoagulation therapy is designed to reduce clotting. Thus, a patient on anticoagulation therapy is expected to have prolonged PT time, reducing the risk of clot formation.
Patient diagnosed with protein S deficiency
increased risk for deep vein thrombosis
Protein S serves to deactivate factors in the clotting cascade. If Protein S is deficient, deactivation of the clotting cascade does not happen as expected, leading to increased risk of clot formation. The increased clot formation may lead to deep vein thrombosis.
Woman, age 35, smokes one pack of cigarettes per day and uses oral contraceptives for birth control
increased risk for clot formation
High estrogen levels, as seen in some oral contraceptives, may increase the synthesis of coagulation factors. This elevates her risk for clot formation. Smoking serves to increase platelet activity, further increasing her risk for clot formation.
Child, having ingested undercooked ground beef, is diagnosed with HUS
increased risk for renal failure
Although the mechanism is not well understood, ingestion of E. coli O157:H7, which may occur with improperly prepared foods, may result in toxin-induced damage to the kidneys. Damage to the kidneys may result in renal failure. Exposure to E. coli and development of HUS have not been shown to be related to development of type 1 diabetes mellitus.
A woman is experiencing extensive menstrual blood loss along with easy bruising
von willebrand factor deficiency
Von Willebrand factor is involved in platelet plug formation. If von Willebrand factor is lacking, excessive bleeding may occur, as evidenced by the woman’s menstrual blood loss and easy bruising. Antithrombin is a natural anticoagulant. If there is a deficiency in this factor, an increased risk for blood clots occurs.
Clinician is concerned about a patient’s vitamin K dietary intake
warfarin
Warfarin interferes with vitamin K-dependent clotting factors. As warfarin effects may vary, close monitoring is necessary. Changes in vitamin K levels in the diet can affect warfarin functioning. Low molecular weight heparin is an anticoagulant, but is not affected by vitamin K levels.
Patient may have drug-induced thrombocytopenia
it is associated with more then 1,500 medications
Many medications can induce thrombocytopenia, including heparin, antimalarial drugs, and sulfonamides.
Laboratory results in critically ill patient with suspected disseminated intravascular coagulation
elevated D-Dimer with diminished fibrinogen
In disseminated intravascular coagulation, both episodes of clot formation and bleeding may occur in a patient. Laboratory results will point to an elevation in clot breakdown, as evidenced by elevated D-dimer levels, along with lower than normal fibrinogen levels, as fibrinogen is consumed in clot formation.
Patient has chronic disorder of bone marrow with megakaryocyte proliferation
essential thrombocytosis
In essential or primary thrombocytosis, an abnormality in the bone marrow results in elevated thrombocytes, or platelets, which are derived from megakaryocytes. Secondary thrombocytosis is the result of some underlying condition, such as cancer, inducing an elevation in platelet number.
Patient who takes aspirin is scheduled for surgery
halt aspirin 7 days before surgery
Aspirin disrupts platelet functioning. Usage of aspirin can result in prolonged bleeding due to this disruption. The effect of aspirin lasts for the lifetime of the platelet, or approximately 7 days. Thus, aspirin should be stopped 7 days before surgery.
Patient appears with abrupt onset of vascular occlusions, hemolytic anemia, and thrombocytopenia
thrombotic thrombo-cytopenic purpura
Although the etiology of thrombotic thrombocytopenic purpura is not known, it can be fatal, with an abrupt onset of hemolytic anemia, vascular occlusions, and thrombocytopenia. In immune thrombocytopenic purpura, antibodies develop against platelets. It may occur in children and may be self-limiting.
Which of the following are steps in hemostasis to prevent blood loss? Select all that apply.
-vasoconstriction
-platelet plug formation
-coagulation
Which factor helps to dissolve clots?
tissue plasminogen activator
Which of the following is NOT commonly associated with bleeding disorders?
decreased prothrombin time
Which of the following may increase the risk of clotting?
primary thrombocytosis
In which disorder are fibrin clots formed rapidly, using up coagulation factors, resulting in increased risk of bleeding?
disseminated intravascular coagulation
