A 1-month-old exclusively breastfed infant who did not receive vitamin K prophylaxis at birth presents with bruising and oozing from a heel stick site. Labs reveal a markedly prolonged prothrombin time (PT) and a moderately prolonged partial thromboplastin time (PTT). Which clotting factors are deficient in this infant?
A 12-year-old boy of Ashkenazi Jewish descent is scheduled for a tonsillectomy. Pre-operative labs reveal a prolonged partial thromboplastin time with a normal prothrombin time. A factor XI level is found to be 15% of normal activity. Which of the following is the most appropriate management for this patient’s perioperative period?
An 11-year-old female presents with a history of menorrhagia and easy bruising. Laboratory evaluation reveals a von Willebrand factor antigen of 65 IU/dL (normal), a von Willebrand factor ristocetin cofactor activity of 25 IU/dL (low), a Factor VIII level of 35% (low), and a normal multimer distribution. Which type of von Willebrand disease is most likely?
A 2-month-old infant presents with a rapidly enlarging vascular lesion on his trunk, profound thrombocytopenia, and hypofibrinogenemia. The peripheral blood smear shows a microangiopathic hemolytic anemia. Which of the following is the most likely diagnosis?
A 10-year-old boy with no personal or family history of bleeding presents with extensive soft tissue bleeding after minor trauma. Laboratory studies show a prolonged partial thromboplastin time that does not correct upon a 1:1 mixing study with normal plasma. What is the most likely underlying cause?
A 9-year-old boy with acute liver failure is bleeding from his intravenous sites. Laboratory studies show a prolonged Prothrombin Time, a prolonged Partial Thromboplastin Time, and thrombocytopenia. You are trying to differentiate the coagulopathy of severe liver disease from disseminated intravascular coagulation. Which of the following laboratory findings would most strongly support a diagnosis of severe liver disease over disseminated intravascular coagulation?
Hemostasis is a balanced process involving clot formation and subsequent clot breakdown. Which enzyme is primarily responsible for the lysis of extraneous fibrin and the restoration of normal blood flow through a previously damaged vessel?
A 12-year-old boy with a mechanical heart valve is managed on long-term warfarin. He presents to the emergency department with a significant gastrointestinal bleed. His international normalized ratio is 8.5. In addition to stopping warfarin and administering intravenous vitamin K, what is the most appropriate immediate intervention to reverse his anticoagulation?
A 16-year-old female develops a deep vein thrombosis in her left leg one month after starting an estrogen-containing oral contraceptive. She has no other risk factors. Testing reveals she is heterozygous for the factor V Leiden pathogenic variant. What is the approximate annual risk of venous thromboembolism in this specific patient population?
A neonatologist is reviewing the blood parameters of a healthy full-term infant at birth. Compared to adult values, which of the following findings is expected in this infant?
