Nokea
Which of the following is a key feature of Factor XIII?
- A. Its half-life is about 10 days.
- B. It is an important activator of thrombin.
- C. Its levels are normal in newborns.
- D. It is part of the contact activation system.
Correct Answer: A
Rationale: Factor XIII has a long half-life of about 10 days, allowing it to play a crucial role in stabilizing fibrin clots. This extended lifespan contributes to the maintenance of clot integrity over time. The other choices are incorrect because Factor XIII is not an activator of thrombin (B), its levels are low in newborns and gradually increase (C), and it is not part of the contact activation system (D).
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You are caring for a patient with a large localized Ewing sarcoma of the soft tissues of the arm. The surgeon believes that the tumor can be resected without amputation but asks whether you can give some chemotherapy to shrink the tumor before surgery. Which of the following would you tell the surgeon?
- A. If the tumor can be resected without amputation, then the best time to do the resection is before any chemotherapy to improve the prognosis.
- B. You agree with waiting to do the resection until week 12 of therapy and will begin chemotherapy; you recognize that radiotherapy will not be necessary if the tumor is completely resected at week 12 of therapy.
- C. You agree with waiting to do the resection until week 12 of therapy and will begin chemotherapy; you recognize that radiotherapy will be necessary even if the tumor is completely resected at week 12 of therapy.
- D. If the tumor can be resected without amputation, then the best time to do the resection is before any chemotherapy; you recognize that this is the only way to avoid radiotherapy.
Correct Answer: B
Rationale: Step 1: Agreeing to wait until week 12 of therapy before resection allows chemotherapy to shrink the tumor, making surgery easier and potentially less extensive.
Step 2: Waiting until week 12 also helps assess the tumor's response to chemotherapy, guiding further treatment decisions.
Step 3: Choosing not to delay the resection until week 12 may risk more extensive surgery or complications due to the tumor's size.
Step 4: Opting for radiotherapy regardless of tumor resection status at week 12 is not advisable as unnecessary radiation exposure should be avoided unless absolutely necessary.
A patient is suffered from vitamin K deficiency. Which of the coagulation factors will not be affected?
- A. Factor II
- B. Factor VII
- C. Factor VIII
- D. Factor IX
Correct Answer: C
Rationale: The correct answer is C: Factor VIII. Factor VIII is not dependent on vitamin K for its synthesis, so its levels will not be affected by vitamin K deficiency. Factor II, VII, and IX are all vitamin K-dependent factors, so their levels will decrease with vitamin K deficiency, leading to impaired blood clotting. This is due to the role of vitamin K in the post-translational modification of these factors, which is necessary for their activation. Therefore, Factor VIII is the only factor that will not be affected by vitamin K deficiency.
Incorrect about pernicious an:
- A. hyperchlorhydria
- B. premature graying of hair
- C. anti intrinsic factor antibody in 60% of pts.
- D. gastric polyp may occur
Correct Answer: A
Rationale: The correct answer is A, hyperchlorhydria. Pernicious anemia is characterized by vitamin B12 deficiency due to lack of intrinsic factor. Hyperchlorhydria refers to high stomach acid production, not a symptom of pernicious anemia. Premature graying of hair and gastric polyp are potential features of pernicious anemia. Anti intrinsic factor antibody presence in 60% of patients is a characteristic finding in pernicious anemia.
Plat. Transfusion is not indicated in:
- A. aplastic an.
- B. uraemia with bleeding
- C. DIC
- D. immunogenic thrombocytopenia
Correct Answer: D
Rationale: The correct answer is D: immunogenic thrombocytopenia. Platelet transfusion is not indicated in immunogenic thrombocytopenia because it involves antibodies attacking platelets, which would render transfused platelets ineffective. Platelet transfusion is indicated in aplastic anemia (A) to increase platelet count, in uremia with bleeding (B) to replace dysfunctional platelets, and in DIC (C) to help manage severe bleeding. In summary, platelet transfusion is contraindicated in immunogenic thrombocytopenia due to ineffective platelet response.
A 9-year-old boy presents to the emergency department with emesis and headache of 3 weeks' duration. MRI reveals a large heterogeneous mass in the cerebellum. He undergoes a resection, and the pathology is most consistent with a classic medulloblastoma. Which of the following findings would classify the patient as a high-risk medulloblastoma?
- A. Elevated serum and CSF AFP and beta-HCG tumor markers
- B. WNT subgrouping on molecular classification
- C. A presurgical spine MRI that reveals bulky tumor in the spine
- D. A postoperative brain MRI with no signs of residual tumor
Correct Answer: C
Rationale: The correct answer is C. A presurgical spine MRI revealing bulky tumor in the spine classifies the patient as high-risk due to leptomeningeal spread. This indicates dissemination of the tumor cells beyond the primary site, leading to a poorer prognosis. Choice A is incorrect as AFP and beta-HCG markers are associated with germ cell tumors, not medulloblastomas. Choice B is incorrect as WNT subgrouping is associated with better outcomes. Choice D is incorrect because the absence of residual tumor postoperatively does not necessarily indicate high-risk disease.