Intraoperative defect in haemostasis in a child receiving valproic acid

This report describes the development of an intraoperative defect in haemostasis which occurred during surgery for lengthening of the heel cords and release of hip contractures in a patient receiving valproic acid. A review of the literature failed to find any other cases of a valproic acid-induced bleeding disorder occurring under anaesthesia and surgery. While recognized in the non-surgical literature, this case reports the first in which the development of a valproic acid-induced haemostatic defect occurred under anaesthesia. The subsequent course is discussed and some pathophysiological mechanisms are presented. It is suggested that for patients receiving valproic acid preoperative education should include PT/PTT, platelet and fibrinogen counts and bleeding time so that abnormal coagulation states can be recognized.