Hemostasis And Its Regulation

5 Questions | By Uscsom_im | Last updated: Mar 21, 2022 | Total Attempts: 447

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Questions and Answers

1.

A 21-year-old woman with no significant medical history presents for evaluation of gingival bleeding. She also complains of heavy menses. She denies having any bleeding problems in the past. Physical examination reveals only gingival bleeding with minimal manipulation. Results of today's laboratory evaluation are as follows: leukocyte count, 8,000; hemoglobin, 14; platelets, 245,000; coagulation, normal. The platelet size is normal. Further evaluation reveals a suboptimal platelet aggregation response to ristocetin. The results of the rest of the aggregation testing are normal. Which of the following is the most likely diagnosis for this patient?
- A.
  
  Vitamin C deficiency
- B.
  
  Vitamin K deficiency
- C.
  
  Von Willebrand disease
- D.
  
  Bernard-Soulier disease
- E.
  
  None of the above
2.

A 45-year-old woman is hospitalized after presenting to the emergency department with dyspnea. She has a history of systemic lupus erythematosus. She is diagnosed with a pulmonary thromboembolism. Her laboratory evaluation is unremarkable except for a partial thromboplastin time (PTT) of 50 sec (before the initiation of any therapy). Anticoagulation therapy is started with an unfractionated heparin drip. In addition, the patient is tested for lupus anticoagulant. The hematologist advises that the patient's anti-factor Xa activity level be monitored to confirm that the heparin level is therapeutic. Of the following, which is a therapeutic anti-factor Xa activity level for this patient?
- A.
  
  0.5 to 1.2 units/ml 4-6 hours after last dose of low-molecular-weight heparin
- B.
  
  0.3-0.7 units/ml
- C.
  
  5 units/ml
- D.
  
  0.1 units/ml
- E.
  
  None of the above
3.

A 54-year-old man with a history of hypertension presents to clinic for preoperative evaluation. He is scheduled to undergo an elective hernia repair. He has a history of easy bruising and of excessive and prolonged bleeding after tooth extractions. Routine laboratory studies are done and the patient's bleeding time is determined. The platelet count and bleeding time are both normal. For this patient, which of the following statements are true?
- A.
  
  He should receive a platelet transfusion before the operation
- B.
  
  A normal bleeding time does not accurately predict risk of hemorrhage
- C.
  
  His surgery should be cancelled
- D.
  
  He is not at risk for excessive bleeding because his platelet count is normal
- E.
  
  None of the above
4.

A 34-year-old woman presents to clinic for a follow-up visit. She had a complicated hospital course 1 year ago. Initially, she was hospitalized with pneumonia and bacteremia. During hospitalization, she developed deep vein thrombosis in her right leg. At the time, a hypercoaguable workup only revealed a low protein S level (the test was performed before the initiation of warfarin). The patient received anticoagulation therapy for 6 months. Repeat laboratory evaluation 6 weeks after completing her warfarin regimen reveals a normal protein S level. For this patient, which of the following statements are true?
- A.
  
  She has protein S deficiency
- B.
  
  She should once again receive anticoagulation therapy
- C.
  
  The initial protein S level was low because the binding protein was increased
- D.
  
  The patient should not have been treated with anticoagulation
- E.
  
  None of the above
5.

An 18-year-old man with a medical history significant for a "bleeding disorder" presents for evaluation of easy bruising. He denies experiencing any bleeding at this time. Results of today's laboratory evaluation are as follows: leukocyte count, 6,000; Hb, 13; platelets, 200,000; prothrombin time, 13 sec; and PTT, 70 sec. His repeat PTT was 67 sec. A mixing study was performed with correction of the PTT. Which of following is the most likely diagnosis?
- A.
  
  Factor VIII deficiency
- B.
  
  Lupus Anticoagulant
- C.
  
  Factor VIII inhibitor
- D.
  
  Glanzmann thrombasthenia
- E.
  
  None of the above