KMU Past Paper Practice

Question:

Following a small vascular injury, a patient has adequate circulating platelets but impaired attachment of platelets to exposed subendothelial collagen. Which interaction is most directly required for this initial step of primary hemostasis?

Options:

Correct Answer:
von Willebrand factor binding platelet GPIb to collagen

Explanation: vWF bridges exposed subendothelial collagen to platelet GPIb, allowing the first platelet attachment after vascular injury.

Question:

Platelets adhere normally at a site of injury and become activated, but they fail to form effective bridges with neighboring platelets. Which interaction is primarily responsible for normal platelet aggregation?

Options:

Correct Answer:
Fibrinogen binding to activated GPIIb/IIIa receptors

Explanation: Activated GPIIb/IIIa binds fibrinogen, which bridges adjacent platelets and produces platelet aggregation.

Question:

A patient generates thrombin and fibrin normally after vascular injury, but the resulting fibrin clot lacks adequate mechanical stability. Which coagulation factor normally performs the final stabilizing step?

Options:

Correct Answer:
Factor XIII

Explanation: Factor XIII cross-links fibrin strands after fibrin formation, producing a mechanically stable clot.

Question:

A coagulation defect produces an abnormal test of the intrinsic pathway while the extrinsic pathway remains preserved. Which group contains factors belonging predominantly to the intrinsic pathway?

Options:

Correct Answer:
VIII, IX, XI and XII

Explanation: Factors XII, XI, IX and VIII constitute the traditional intrinsic pathway and are assessed mainly by aPTT.

Question:

A patient develops thrombocytopenia after treatment that markedly suppresses bone-marrow activity. Unlike immune thrombocytopenia, the marrow is unable to mount an adequate platelet-producing response. Which mechanism best accounts for the low platelet count?

Options:

Correct Answer:
Reduced platelet production

Explanation: Bone-marrow suppression decreases megakaryocyte activity and therefore reduces platelet production rather than increasing peripheral destruction.

Question:

A severely injured patient loses a large volume of blood and receives extensive replacement with fluids and blood components lacking adequate platelets. The platelet count subsequently falls despite previously normal marrow function. What is the most likely mechanism?

Options:

Correct Answer:
Dilution of circulating platelets

Explanation: Major blood-volume replacement can dilute the patient’s circulating platelets, producing dilutional thrombocytopenia.

Question:

A young woman with isolated thrombocytopenia is found to have IgG bound to circulating platelets. Which platelet structures are important antigenic targets in the pathogenesis of this disorder?

Options:

Correct Answer:
GPIIb/IIIa and GPIb-containing complexes

Explanation: ITP commonly involves IgG autoantibodies against platelet membrane glycoproteins, particularly GPIIb/IIIa and GPIb-containing complexes.

Question:

A 30-year-old woman has symptomatic immune thrombocytopenia with bruising and mucosal bleeding but no immediately life-threatening hemorrhage. Which therapy most directly reduces the immune process responsible for platelet loss?

Options:

Correct Answer:
Corticosteroid therapy

Explanation: Corticosteroids suppress immune-mediated platelet destruction and are a major treatment approach for symptomatic ITP.

Question:

A patient with known immune thrombocytopenia develops a life-threatening intracranial hemorrhage with profound thrombocytopenia. In addition to treatment directed at the immune process, which supportive intervention is appropriate because of the immediate bleeding risk?

Options:

Correct Answer:
Platelet transfusion

Explanation: Platelet transfusion is generally reserved for major or life-threatening bleeding in ITP because transfused platelets may also undergo immune destruction.

Question:

A woman with recurrent epistaxis and heavy menstrual bleeding has a normal platelet count and a normal prothrombin time. Further testing supports von Willebrand disease. Why can the prothrombin time remain normal in this condition?

Options:

Correct Answer:
The extrinsic coagulation pathway remains intact

Explanation: PT assesses the extrinsic and common pathways, which are not primarily defective in von Willebrand disease.

Question:

A boy has recurrent deep bleeding. His maternal uncle had a similar disorder, while his father is unaffected. Factor assay confirms hemophilia. Which inheritance pattern best explains this family history?

Options:

Correct Answer:
X-linked recessive inheritance

Explanation: Hemophilia A and B classically follow X-linked recessive inheritance, producing disease mainly in males through carrier females.

Question:

A 17-year-old boy with severe hemophilia has experienced repeated episodes of bleeding into both knees since childhood. He now has chronic pain and limitation of movement. Which process most directly explains the current joint problem?

Options:

Correct Answer:
Progressive damage from recurrent hemarthroses

Explanation: Repeated bleeding into joints causes chronic structural damage and can lead to hemophilic arthropathy.

Question:

A boy with hemophilia initially appears to stop bleeding after a minor procedure, but bleeding restarts several hours later. Platelet number and function are preserved. Which defect best explains the delayed bleeding?

Options:

Correct Answer:
Inadequate fibrin reinforcement of the platelet plug

Explanation: Primary hemostasis can occur in hemophilia, but defective secondary hemostasis prevents adequate fibrin stabilization of the initial plug.

Question:

A patient with established hemophilia A develops significant bleeding after trauma. The clinician wants to correct the deficient coagulation protein directly. Which treatment best addresses the underlying defect?

Options:

Correct Answer:
Factor VIII replacement

Explanation: Hemophilia A results from factor VIII deficiency, so factor VIII replacement directly restores the missing coagulation activity.

Question:

A patient with a coagulation-factor deficiency requires an adjunct that reduces fibrin clot breakdown. Tranexamic acid is unavailable. Which alternative drug works through the same general antifibrinolytic principle?

Options:

Correct Answer:
Aminocaproic acid

Explanation: Aminocaproic acid, like tranexamic acid, inhibits fibrinolysis and helps preserve an already formed fibrin clot.

Question:

A patient begins antifibrinolytic therapy for recurrent bleeding and subsequently reports nausea and abdominal discomfort without evidence of thrombosis. Which adverse effect category best fits these symptoms?

Options:

Correct Answer:
Gastrointestinal adverse effects

Explanation: Antifibrinolytic drugs can cause gastrointestinal symptoms such as nausea and abdominal discomfort in addition to concern about thrombosis.

Question:

A hematopoietic supportive drug is prescribed to increase platelet production by promoting megakaryocyte development and maturation. The pharmacological agent is a recombinant form of which mediator?

Options:

Correct Answer:
Interleukin-11

Explanation: Oprelvekin is recombinant interleukin-11 and promotes megakaryocyte maturation, thereby increasing platelet production.

Question:

A patient with a newly diagnosed hematological malignancy develops a rapidly evolving consumption coagulopathy with diffuse bleeding. Which malignancy is a particularly important association with this complication?

Options:

Correct Answer:
Acute promyelocytic leukemia

Explanation: Acute promyelocytic leukemia is an important malignancy associated with DIC and may produce severe consumption of hemostatic factors.

Question:

A patient suffers extensive crush injuries in a road traffic accident. Several hours later, laboratory findings indicate systemic activation of coagulation with consumption of platelets and clotting factors. Which aspect of the original injury most strongly predisposed to this process?

Options:

Correct Answer:
Extensive tissue injury

Explanation: Major trauma and extensive tissue injury can strongly activate systemic coagulation and precipitate DIC.

Question:

A patient with systemic coagulation activation develops widespread fibrin deposition. At the same time, the body attempts to remove the deposited fibrin, contributing further to the complex bleeding pattern. Which process is responsible for this response?

Options:

Correct Answer:
Secondary activation of fibrinolysis

Explanation: Widespread fibrin formation in DIC activates secondary fibrinolysis, producing fibrin breakdown products and contributing to the bleeding tendency.