High prevalence of acquired von Willebrand's syndrome in patients with thyroid diseases undergoing thyroid surgery.

Various coagulation abnormalities occur in patients with thyroid diseases. These abnormalities range from subclinical laboratory findings to hemorrhage or thromboembolism. However, the prevalence of hemostatic abnormalities in patients with thyroid diseases is still unclear.Between January 1999 and December 2003, 1342 consecutive patients with various thyroid diseases who were candidates for thyroid surgery underwent preoperative screening of hemostatic parameters including prothrombin time, activated partial thromboplastin time and platelet-related hemostasis with the PFA-100 platelet-function analyzer.Thirty-nine patients (2.9%) had abnormalities of the coagulation screening tests. Of these, 35 patients had von Willebrand's disease (type 1 in 33 cases and type 2A in 2 cases), 2 patients had decreased platelet aggregability, and 2 patients had coagulation factor XI deficiency. As all patients with coagulation abnormalities responded to subcutaneous desmopressin injection (0.3 microg/Kg BW), this drug was successfully used as surgical prophylaxis.Up to 3% of patients with thyroid diseases undergoing thyroid surgery have coagulation abnormalities, in most cases resembling von Willebrand's disease. Coagulation screening tests are needed in order to identify those patients at increased risk of bleeding.