Chronic subdural haematomas and anticoagulation or anti-thrombotic therapy.

Eighty-one cases of chronic subdural haematomas (CSDH) admitted to the neurosurgical unit of the Royal Hobart Hospital, Tasmania, Australia, over a 5-year period were reviewed. The use of anticoagulant therapy as a causative agent in the development of CSDH was investigated. We suspected a high incidence of anticoagulant or anti-thrombotic therapy. We found that anticoagulant therapy was used by a significant percentage of CSDH patients. In the patient group presenting to our unit the risk of developing a CSDH was at least 42.5 times higher in warfarinised patients and also increased for patients on aspirin, although this risk could not be quantified.