A 3-year-old boy comes to the emergency department for evaluation of oral bleeding that began 1 hour after a tooth extraction. The bleeding has persisted for approximately 30 minutes despite application of constant pressure with gauze. He has no significant past medical or surgical history. The patient takes no medications, and his vaccinations are up to date. Blood pressure is 90/60 mm Hg and pulse is 100/min. On physical examination, he has slow oozing of blood at the site of the dental extraction. Family history is significant for a maternal uncle who suffered from recurrent bleeding into his joints. Which of the following is most likely to be abnormal in this patient?

Question

A 3-year-old boy comes to the emergency department for evaluation of oral bleeding that began 1 hour after a tooth extraction.  The bleeding has persisted for approximately 30 minutes despite application of constant pressure with gauze.  He has no significant past medical or surgical history.  The patient takes no medications, and his vaccinations are up to date.  Blood pressure is 90/60 mm Hg and pulse is 100/min.  On physical examination, he has slow oozing of blood at the site of the dental extraction.  Family history is significant for a maternal uncle who suffered from recurrent bleeding into his joints.  Which of the following is most likely to be abnormal in this patient?

Quizplus · Accepted Answer

11ec160b_397d_a6de_9249_e96e0c474d84_MD0001_00 Abnormal bleeding following tooth extractions or other surgical procedures can signify a quantitative or qualitative platelet defect, coagulopathy, or abnormal fibrinolysis. This patient's male sex and family history of hemarthrosis in a maternal male relative suggest an X-linked coagulopathy such as hemophilia A (factor VIII deficiency) or hemophilia B (factor IX deficiency, Christmas disease). Hemophilia A and B are indistinguishable clinically as both demonstrate similar symptoms and inheritance patterns. Both conditions are characterized by isolated prolongation of partial thromboplastin time due to defects in the intrinsic coagulation pathway. Prothrombin time [PT] and thrombin time [TT] are normal in patients with hemophilia. When endothelial injury occurs, platelets are activated and form a hemostatic plug first, followed by activation of the coagulation cascade. Patients with hemophilia have normal platelet function and can form a platelet plug, so bleeding after procedures can be delayed rather than immediate, in contrast to patients with platelet disorders. Manifestations include intramuscular hemorrhage, hemarthrosis, and prolonged or delayed bleeding after surgical procedures. (Choice A) Low haptoglobin is a sign of hemolytic anemia. Other associated findings include increased indirect bilirubin and lactate dehydrogenase. (Choice B) This patient's hemoglobin level is likely normal since the oozing began recently and he has no history of chronic or recurrent bleeding. (Choice D) Signs of thrombocytopenia include easy bruisability, petechiae, and mucocutaneous hemorrhage (eg, recurrent epistaxis, gingival hemorrhage). The absence of petechiae and the delayed bleeding onset make a platelet disorder unlikely. (Choice E) The platelet function analyzer (PFA-100) test monitors the time needed for a patient's blood to form a platelet-based hemostatic plug in an in vitro environment. Abnormal results are seen in von Willebrand disease, inherited/acquired platelet dysfunction (eg, NSAID use), and thrombocytopenia. (Choice F) PT reflects the extrinsic clotting pathway, which involves tissue factor, fibrinogen, and factors II, V, VII, and X. Vitamin K deficiency and warfarin anticoagulant therapy are common causes of isolated PT prolongation as they lead to decreased activity of factors II, VII, IX, and X. Inherited deficiencies of these clotting factors are very rare. (Choice G) The TT measures the rate of conversion of fibrinogen to fibrin. It is prolonged in patients with deficient or defective fibrinogen, which can be congenital or acquired. The most common cause of acquired dysfibrinogenemia is liver disease. Educational objective: Hemophilia is an X-linked recessive coagulopathy that presents with intramuscular hemorrhage, hemarthroses, and delayed bleeding after procedures. Laboratory results show partial thromboplastin time prolongation; other tests of hemostatic function are generally normal. __________ References: Bleeding and bruising: a diagnostic work-up. (http://www.ncbi.nlm.nih.gov/pubmed/18481559) Diagnosis and management of von Willebrand disease: guidelines for primary care. (http://www.ncbi.nlm.nih.gov/pubmed/19961139)

A 3-Year-Old Boy Comes to the Emergency Department for Evaluation