Late postoperative hemorrhage in a patient with undiagnosed COX-1 deficiency after third molar extractions.

Oral maxillofacial surgeons direct invasive procedures that often cause significant bleeding. Uncontrolled hemorrhage is a rare, yet serious, complication that can be seen in patients with thrombocytopathy. Platelets have 3 distinct roles in coagulation: initial adhesion, phospholipid externalization, and platelet aggregation.(1) Several types of platelet deficiencies, including defects of adhesion (Bernard-Soulier syndrome), defects of aggregation (Glanzmann thrombasthenia), and disorders of platelet secretion due to a deficiency of adenosine diphosphate (ADP) or cyclooxygenase-1 (COX-1).(2-4) COX has 2 isoforms: COX-1 and COX-2.(5,6) COX-1 is expressed constitutively in most tissues, and COX-2 is induced primarily by inflammatory mediators.(7,8) Although both isoforms are present in platelets, COX-1 is the major isoform that contributes to coagulation, because it is critically important in the formation of thromboxane A2 (TXA2) by way of the arachidonic acid (AA) pathway.(9) AA is a potent inducer of platelet aggregation.(1,3,4) When AA is exposed to an activating agent, such as ADP, it undergoes a series of enzymatic reactions that culminates in the production of TXA2.(10) TXA2 is the predominant product of the COX-1 pathway and is a major metabolite of AA in platelets. TXA2 is necessary for normal platelet function. Therefore, the inhibition of, or a deficiency in, COX-1 will compromise the AA pathway, thereby reducing platelet secretion and altering normal platelet aggregatory function.(1,3) COX-1 deficiencies are usually caused by drug interactions with the enzyme itself. In addition, studies have identified genetic mutations that can result in COX-1 deficiency.(2) We present the hospital course, management, and diagnosis of a patient with an undiagnosed COX-1 deficiency who had had third molars removed in a private office. To our knowledge, this is the first case of COX-1 deficiency diagnosed after exodontia documented in English studies. In addition, we reviewed the published data of this rare disorder that has significant clinical implications.