A 7-year-old boy is brought to the physician for a follow-up examination after the removal of a tooth. During the procedure, he had prolonged bleeding that did not resolve with pressure and gauze packing and eventually required suture placement. His older brother had a similar episode a year ago, but his parents and two sisters have never had problems with prolonged bleeding. Physical examination shows no abnormalities. Genetic analysis confirms an X-linked recessive disorder. Which of the following is most likely deficient in this patient?
AProtein C
BFactor VIII
CVon Willebrand factor
DFactor IX
EFactor XI
A 28-year-old man presents for severe abdominal pain and is diagnosed with appendicitis. He is taken for emergent appendectomy. During the procedure, the patient has massive and persistent bleeding requiring a blood transfusion. The preoperative laboratory studies showed a normal bleeding time, normal prothrombin time (PT), an INR of 1.0, and a normal platelet count. Postoperatively, when the patient is told about the complications during the surgery, he recalls that he forgot to mention that he has a family history of an unknown bleeding disorder. The postoperative laboratory tests reveal a prolonged partial thromboplastin time (PTT). Which of the following is the most likely diagnosis in this patient?
Avon Willebrand disease
BBernard-Soulier syndrome
CThrombotic thrombocytopenic purpura
DHemophilia A
EGlanzmann thrombasthenia
A 30-year-old woman presents to the emergency department in a state of confusion and disorientation that started this morning. She is accompanied by her husband who says that she has been unwell for about one week. She has been complaining of fatigue. Her husband says that this morning, she also complained that her urine was dark red in color and that there were some red spots over her legs. He did notice some changes in her level of consciousness that worsened over time and he decided to bring her in today. She does not have a significant medical history. Physical examination shows petechiae over her arms and legs. She is conscious but drowsy and disoriented and unable to answer the physician’s questions appropriately. Her temperature is 38.3°C (100.9°F), blood pressure is 160/100 mm Hg, pulse rate is 90/min, and respiratory rate is 20/min. Laboratory studies show: Hemoglobin 10 g/dL Leukocyte count 9,000/mm3 Platelet count 30,000/mm3 Bleeding time 10 min Prothrombin time 12 s Activated partial thromboplastin time 30 s D-dimer 0.4 mg/L (normal < 0.5 mg/L) Serum fibrinogen 350 mg/dL (normal 200–400 mg/dL) Serum bilirubin (indirect) 2.2 mg/dL Serum creatinine 1.5 mg/dL Serum LDH 1,010 U/L Based on her history, and her physical and laboratory findings, which of the following is the most likely pathophysiology for her presentation?
AGPIIb/IIIa deficiency and failure of platelet aggregation
BSystemic activation of blood coagulation
CE. coli-mediated endothelial damage and formation of microthrombi
DAntiplatelet antibodies
EDecreased ADAMTS13 causing platelet adhesion and formation of microthrombi
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