A number of procedures that are performed in dentistry may cause bleeding. Under normal circumstances, these procedures can be performed with little risk; however, patients whose ability to control bleeding is altered by congenital defects in coagulation factors, platelets, or blood vessels may be in grave danger unless the dentist identifies the problem before performing any dental procedure. In most cases, after a patient with a congenital bleeding problem has been identified, steps can be taken to greatly reduce the risks associated with dental procedures.
The following disorders are discussed in this chapter: hereditary hemorrhagic telangiectasia (Osler-Weber-Rend syndrome), von Will brand disease, Bernard-Soupier disease, Clansman thrombasthenia, hemophilia A, hemophilia B (Christmas disease), and congenital hypercoagulability disorders. Inherited (congenital) bleeding disorders are genetically transmitted.
They may involve a deficiency of one of the coagulation factors, abnormal construction of platelets, deficiency of von Will brand factor, or malformation of vessels (Box 25.1). They are not as prevalent as acquired bleeding disorders. In a typical dental practice of 2000 patients, at the most 10 to 20 patients will have a congenital bleeding disorder.
Inherited hypercoagulability disorders increase the risk for thromboembolism caused by a genetic deficiency of an antithrombotic factor or increasing a prothrombotic factor. They are more common than the inherited bleeding disorders.
The disease usually is inherited as an autosomal dominant trait.1 Hemophilia A, factor VIII deficiency, is the most common of the inherited coagulation bleeding disorders.2 It occurs in about 1 of every 5000 male births. More than 20,000 individuals in the United States have hemophilia A,3,4 and worldwide about 400,000 patients have severe hemophilia.
2 Because of its genetic mode of transfer, certain areas of the United States contain higher concentrations of people with hemophilia. Hemophilia B (Christmas disease), a factor IX deficiency, is found in about 1 of every 30,000 male births.4 About 80% of all genetic coagulation disorders are hemophilia A, 13% are hemophilia B, and 6% are factor XI deficiency.
BernardSoulier disease and Glanzmann thrombasthenia are rare inherited platelet disorders.1,5 Hereditary hemorrhagic telangiectasia (HHT) is a rare (1:8000 to 1:50,000) vascular disorder.6 Ehlers-Danlos disease, osteogenesis imperfecta, pseudoxanthoma elasticum, and Marfan syndrome are rare hereditary connective tissue disorders that may be associated with bleeding problems but are not covered in this chapter.1 An inherited hypercoagulable state has been reported in more than 60% of patients presenting with idiopathic venothromboembolism.