Final answer:
The 15-year-old girl's symptoms and history suggest a bleeding disorder likely due to platelet function defect or a vascular disorder. Desmopressin is the most suitable treatment, as it aids in improving platelet function and is commonly used in conditions like von Willebrand disease.
Step-by-step explanation:
Understanding Hemostasis and Appropriate Treatment
The clinical presentation of a 15-year-old girl with excessive bleeding following dental surgery, prolonged menses, recurrent epistaxis, and a family history of postpartum bleeding suggests a bleeding disorder. The physical examination finding of scattered petechiae and her laboratory results provide further evidence of a hemostatic issue. Although her platelet count is normal, the crucial finding in her laboratory analysis is the prolonged bleeding time, which indicates a potential defect in platelet function or a vascular disorder.
In this case, Desmopressin (B) is the most appropriate treatment. Desmopressin is a medication that can be used to treat certain types of bleeding disorders such as von Willebrand disease (VWD) or mild hemophilia A, as it helps to increase levels of von Willebrand factor and factor VIII, leading to improved platelet function and clot formation. Though other options like Factor VIII concentrate (C) and Plasmapharesis (A) are treatments for specific coagulation factor deficiencies (e.g., hemophilia A), the given laboratory results do not indicate a deficiency in coagulation factors, as both PT and aPTT are within normal ranges.
The other listed treatment options are not suitable because they do not address the likely underlying cause of the bleeding disorder in this patient. Hydroxyurea (D) is used in chronic myeloid leukemia and other myeloproliferative disorders, and Splenectomy (E) is a surgical procedure that may be indicated in conditions like immune thrombocytopenic purpura (ITP) where the spleen is implicated in the destruction of platelets, neither of which are indicated here.