Neonatal idiopathic cerebral venous thrombosis: an unrecognized cause of transient seizures or lethargy.

Seven neonates who presented with either lethargy (four infants) or seizures (three infants) were found by magnetic resonance (MR) phase imaging to have idiopathic cerebral venous thrombosis (CVT). Examination showed only hypotonia or hyperreflexia. The presence of CVT was suggested by unenhanced cranial computed tomographic (CT) scans. Conventional MR T1- and T2-weighted images often indicated more extensive thromboses than were suggested by cranial CT. In all infants, MR phase imaging confirmed thromboses by establishing absence of blood flow in cerebral veins or sinuses. No infant received anticoagulation. Lethargy slowly resolved and seizures did not recur. Normal development has been observed thus far in brief follow-up. The occurrence of seven infants with idiopathic neonatal CVT within a 3-month period indicates that CVT may be a cause of neonatal seizures or lethargy of unclear cause. MR phase imaging provides a powerful, noninvasive means of confirming the diagnosis. Treatment with anticoagulants does not appear necessary.