There is insufficient information on the prognosis and safety of anticoagulation in acute cerebral vein and dural sinus thrombosis (CVDST). To describe the clinical aspects and medical management of CVDST in Portuguese hospitals, to evaluate the safety of anticoagulation in this setting, and to identify subgroups of CVDST patients with different prognoses, we registered symptomatic CVDST patients admitted to Portuguese hospitals since 1980. Cases were collected from file review up to 6/95 and from consecutively admitted patients from 6/95 to 6/98. One hundred and forty-two patients were included from 20 centers (51 retrospectively and 91 prospectively). One hundred and twelve patients (79%) were anticoagulated. There were only 6 new intracranial hemorrhages (4 in anticoagulated patients) and 2 systemic hemorrhages. Nine (6%) patients died. At discharge, 96 (68%), had recovered completely and only 6 (4%) were dependent (Rankin > or = 3). Significant multivariate predictors of death/dependency were central nervous system infection as a predisposing cause (odds ratio, OR = 15.4; 95% confidence interval CI = 111-1.1), encephalopathy on admission (OR = 5.2; 95% CI = 18.7-1.5) and hemorrhage on admission CT/MR (OR = 3.6; 95% CI = 12.9-1). Significant predictors of complete recovery were no encephalopathy on admission (OR = 5; 95% CI = 12.5-2.1), age < 45 years (OR = 3.8; 95% CI = 9.2-1.6) and anticoagulation (OR = 3.8; 95% CI = 9.6-1.5). It is possible to identify CVDST patients with potential bad or good prognosis in the acute phase. Anticoagulation was safe and a predictor of complete recovery in acute CVDST. Copyright 2001 S. Karger AG, Basel