A 9-year-old girl is brought to the emergency department due to prolonged epistaxis. The girl says that she picked her nose immediately before the bleeding started. Her parents decided to bring her to the emergency department after the epistaxis persisted for 20 minutes despite constant compression of the nasal alae. The patient has had frequent nosebleeds that often last 10 minutes. Her family history is significant for a grandfather who had an unspecified bleeding disorder. Given the history of prolonged, recurrent nosebleeds, laboratory tests are ordered, and results are as follows: Which of the following is the most likely diagnosis?

Question

A 9-year-old girl is brought to the emergency department due to prolonged epistaxis.  The girl says that she picked her nose immediately before the bleeding started.  Her parents decided to bring her to the emergency department after the epistaxis persisted for 20 minutes despite constant compression of the nasal alae.  The patient has had frequent nosebleeds that often last >10 minutes.  Her family history is significant for a grandfather who had an unspecified bleeding disorder.  Given the history of prolonged, recurrent nosebleeds, laboratory tests are ordered, and results are as follows:  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_399a_08be_9249_ff5227a66ff5_MD0001_00 This patient has a normal prothrombin time (PT) and thrombin time (TT) and a prolonged partial thromboplastin time (PTT), indicating a defect in the intrinsic pathway (coagulation factors VIII, IX, XI, or XII). Bleeding time is a test of platelet function and is prolonged by qualitative and quantitative platelet defects. The term "bleeding time" refers to this particular test and not the duration of bleeding, which can be prolonged from other coagulopathies. von Willebrand disease (vWD) will cause both a prolonged PTT and bleeding time. von Willebrand factor (vWF) is produced by endothelial cells and megakaryocytes and functions as a carrier protein for factor VIII and as a mediator of platelet adhesion to the endothelium. Absence of vWF leads to impaired platelet function and coagulation pathway abnormalities. vWD is inherited in an autosomal dominant fashion with variable penetrance and is the most common heritable bleeding disorder. (Choice A) Disseminated intravascular coagulopathy (DIC) is a consumptive coagulopathy most commonly seen in septic shock. PT, PTT, and bleeding time are prolonged, and the D-dimer, a degradation product of cross-linked fibrin, is elevated. (Choice B) Dysfibrinogenemias are inherited abnormalities in the fibrinogen molecule that can cause excessive bleeding or thrombophilia. TT, PT, and PTT are abnormal in this condition, but bleeding time is unaffected. (Choice C) Factor XIII is a transglutaminase that cross-links fibrin polymers, thereby stabilizing clots. Factor XIII deficiency causes spontaneous or excessive bleeding, but it would not prolong the bleeding time, PT, or PTT. (Choice D) Hemophilia A is an X-linked hereditary deficiency of factor VIII that causes coagulopathy with a prolonged PTT but shows normal bleeding time. (Choice E) Hemophilia B is an X-linked hereditary deficiency of factor IX that causes coagulopathy with a prolonged PTT but shows normal bleeding time. (Choice F) Vitamin K is required for activation of clotting factors II, VII, IX, and X. Vitamin K deficiency causes a coagulopathy that primarily prolongs PT, with PTT prolongation occurring in severe cases. Bleeding time is not affected. Educational objective: von Willebrand disease is the most common inherited bleeding disorder. It has an autosomal dominant pattern of inheritance and variable penetrance. Absence of von Willebrand factor leads to impaired platelet function (prolonged bleeding time) and coagulation pathway abnormalities due to decreased factor VIII activity (prolonged partial thromboplastin time). __________ References: Diagnosis and Management of Von Willebrand disease: guidelines for primary care (http://www.ncbi.nlm.nih.gov/pubmed/19961139) Of von Willebrand factor and platelets. (http://www.ncbi.nlm.nih.gov/pubmed/25297919) Bleeding and Bruising: A Diagnostic Work-up (http://www.ncbi.nlm.nih.gov/pubmed/18481559)

A 9-Year-Old Girl Is Brought to the Emergency Department Due