Disclaimer: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. Bleeding Disorders in Pediatric Otolaryngology Bleeding disorders may complicate many routine otolaryngology procedures. This may result from technical errors, but bleeding associated with defects in the coagulation system may be difficult to control. All otolaryngologists should be aware of common bleeding disorders and their treatment. Normal coagulation may be divided into three phases: vascular response, platelet activation, and the coagulation cascade. The initial vascular response of vasoconstriction occurs immediately after the injury. Platelet adherence occurs in response to collagen exposure by endothelial damage. Further platelet adhesion is mediated through specific platelet receptors and mediators creating an unstable hemostatic plug. Coincident with the platelet activation, the coagulation cascade is initiated by the release of tissue thromboplastin and contact-activating factors. The coagulation cascade forms a fibrin matrix that reinforces the platelet plug. Defects of the Factor VIII macromolecule are associated with the two most common inherited coagulation disorders, hemophilia A and von Willebrand's Disease. The Factor VIII macromolecule is a high molecular weight glycoprotein present in small amounts in normal plasma. This factor is composed of three component factors VIII:C, Factor VIII:RAg, and Factor VIII:VW. Factor VIII:C is the procoagulant component that is important in the coagulation cascade and is deficient in Hemophilia A. Factor VIII:RAg is the antigenic determinant for the molecule and links the two components together. The Factor VIII:VW is the von Willebrand's factor that is important in platelet activation and adhesion and is deficient in von Willebrand's Disease. The evaluations of bleeding disorders require a thorough history and physical exam. Suspicion of a bleeding disorder is often initiated by an abnormal laboratory test, but history and physical exam are very effective. Important questions include prolonged bleeding following minor trauma, spontaneous bruising, or hematoma formation. Because surgery is a thorough challenge to the hemostatic system, any history of excessive bleeding with prior surgical procedures may indicate a bleeding disorder. Drug history is important since many drugs cause bleeding. Aspirin and other cycloxygenase inhibitors are the most common drugs associated with bleeding disorders and each patient should be questioned carefully about their use. Every patient should be questioned regarding family history and any possible pattern of inheritance. The physical exam may provide important clues as well. Petechiae and purpura are signs of platelet dysfunction. Large firm bruises with nodular centers are commonly seen in congenital factor deficiencies. Icterus and hepatosplenomegaly are indicative of liver disease, which be associated with bleeding disorders. Basic laboratory evaluation of coagulation disorders consists of platelet count, prothrombin time, partial thromboplastin time, and bleeding time. Other more specialized tests include qualification of specific factor levels and tests of platelet function. Platelet count is an important initial test since thrombocytopenia is the most common cause of bleeding. If platelet count is normal and platelet dysfunction is suspected, tests of platelet adhesion may be needed. The bleeding time is an in vivo assessment of platelet response to limited vascular injury and is reflective of the integrity of the primary hemostatic mechanism. Bleeding time is prolonged in thrombocytopenia, qualitative platelet disorders, von Willebrand's Disease, fibrinolytic states, afibrinogenemia, vasculitis, and aspirin therapy. The partial thromboplastin time tests all factors of the classic intrinsic cascade and all factors of the extrinsic cascade with the exceptions of factor VII. The PT tests the extrinsic pathway, in particular vitamin K dependent factors X, VII, V, II, and fibrinogen. Specific factor levels may be tested as well. The most common factor to be tested in Factor VIII which tests each component of this molecule. Factor IX is often commonly measured since Hemophilia C is the third most common inherited bleeding disorder. Bleeding disorders may be divided into vascular, platelet, coagulation factor, and multiple compartment defects. Vascular disorders may be hereditary or acquired and are characterized by abnormalities in the vascular blood interface that impairs platelet adhesion. Laboratory tests are characterized by a prolonged bleeding time. Examples of hereditary disorders include hereditary hemorrhagic telangiectasia, Ehlers-Danlos syndrome, Marfan's syndrome, osteogenesis imperfecta, pseudoxanthoma elasticum, and homocystinurea. Acquired vascular disorders result from insults to the vascular blood interface. Examples of these include malignant paraprotein disorders, amyloidosis, lupus, scleroderma, rheumatoid arthritis, Cushing's syndrome. Platelet disorders are characterized by petechiae, purpura, mucosal membrane bleeding, and bruisibility. Examples of congenital platelet disorders include Thrombocytopenia absent radius syndrome, Amegkaryocytic Thrombocytopenia, Glanzmann's Thrombasthenia and Bernard-Soulier Syndrome. Acquired platelet disorders include immune thrombocytopenic purpura; drug induced, infectious thrombocytopenia; and renal failure. Viral infections are a common cause of immune and infectious thrombocytopenia. Aspirin and other cyclooxygenase inhibitors are the most common cause of drug induced platelet dysfunction. This occurs due to the inhibition of synthesis of thromboxane A potent stimulator of platelet activation. Hemophilia A and von Willebrand's Disease are the most common congenital coagulation disorders and both involve different components of factor VIII macromolecule. Hemophilia A or classic hemophilia is inherited as a sex-linked recessive and is a deficiency or defect in factor VIII:C. Disease severity is determined by the circulating levels of Factor VIII:C. Treatment consists of Factor VIII:C replacement. Von Willebrand's Disease is characterized by a deficiency or dysfunction of the Factor VIII:VW resulting in impaired platelet adhesion. This disorder is inherited as a autosomal dominant and is characterized by bleeding from mucocutaneous surfaces. Symptoms vary tremendously with each patient, but excessive bleeding may occur with trauma or surgery. Treatment is with cryoprecipitate replacement. Hemophilia B and Hemophilia C occur less commonly. Acquired coagulation factor disorders may result from circulating anticoagulants or from vitamin K deficiency. Newborn and premature babies are at risk for hemorrhagic symptoms due to vitamin K deficiency particularly if the mother has been taking vitamin K antagonists. Disseminated intravascular coagulation (DIC) and liver failure affect the coagulation system at multiple levels. DIC occurs with activation of both the coagulation and fibrinolytic system resulting in thrombosis and hemorrhage. This may occur secondary to trauma, placental abruptio, sepsis, ARDS, and a variety of other disorders. While the hemorrhage is obvious, thrombosis of small and medium vessels accounts for the majority of morbidity and mortality. Treatment consists of treating the inciting disease process, but some cases require anticoagulation to prevent further thrombosis. Liver failure results in bleeding due to deficiencies of coagulation factors and disruption of platelet function. Treatment consists of blood product replacement. Preoperative screening for bleeding disorders remains a very controversial subject. Most bleeding disorders are obvious and are diagnosed prior to surgery. A small number of cases of mild Hemophilia or Von Willebrand's Disease may be uncovered at the time of surgery. Several studies have looked at the effectiveness of preoperative screening for adenotonsillectomy. Bolger et al found six coagulation disorders in 52 patients undergoing preoperative screening for adenotonsillectomy. Based on their experience they recommended preoperative screening in all patients undergoing adenotonsillectomy. In a retrospective review of 994 patients undergoing adenotonsillectomy, Manning et al found that preoperative PT/PTT failed to identify any patients with occult coagulopathies. In another study, Burk et al performed a retrospective review of 1603 patients undergoing adenotonsillectomy. Preoperative screening , a careful bleeding history is used to identify any potential bleeding disorders and guide further laboratory disorders. Hutchinson revised a questionnaire originally written by Rappaport. Reviewing these questions with each patient or parent will identify many bleeding disorders.
Otolaryngologists should be familiar with common bleeding disorders since many have head and neck manifestations. In addition, this knowledge base will allow for appropriate preoperative screening of surgical patients. The most important component of the preoperative assessment is the bleeding history that directs further laboratory evaluation. Case Presentation A 5-year-old white male child was referred to the Otolaryngology Clinic for a persistent bleeding and hematoma following a laceration of the forehead. Ten days prior to this visit he sustained a laceration on his forehead while playing on a playground. He was taken to his local emergency room where the laceration was sutured, but the wound took a long time to stop bleeding. Sutures were removed at one week. Following suture removal he continued to have occasional bleeding from the laceration with a persistent swelling. Past surgical history was remarkable for circumcision and ear tube insertion. The circumcision was uneventful, but the ear tube insertion was complicated by postoperative bleeding requiring a visit to the emergency room. He also had a history of intermittent epistaxis. The family history was unremarkable for documented bleeding disorders, but an uncle had a questionable history of excessive bleeding. He had no history of aspirin use, but had been prescribed DDAVP for enuresis. Physical exam revealed a 2 cm laceration over the glabella with underlying hematoma and mild bleeding from the laceration. A coagulation battery was obtained. The PT and platelet count were normal, but the PTT was mildly elevated and bleeding time was prolonged. Hematology consultation was obtained to further define this bleeding disorder. A von Willebrand's profile and factor IX level were obtained. Factor IX level and Factor VIII:C were normal. The Factor VIII:VW was decreased to 37% (51-151%) consistent with Type 1 von Willebrand's Disease. 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