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Sigmoid sinus thrombosis after closed head injury in children.

In the literature, clinical descriptions of sigmoid sinus thrombosis occurring after closed head injury in children are rare. One to 5 days after trauma to the back of the head, five children (aged 1 to 7 yr) presented with gait ataxia, vomiting, and headache. Trauma was mild in four children. Computed tomography of all the children, performed within 5 days after the injury, showed focal hyperdensity in the region of the left sigmoid sinus. Four children had extra-axial hyperdense collections along the left transverse sinus, and three had skull fractures adjacent to the left sigmoid sinus. Magnetic resonance imaging (MRI) of all the children, performed 2 to 6 days after injury, showed left sigmoid-sinus thrombosis and decreased flow or thrombosis within the lateral third of the left transverse sinus. All the children had MRI scans 4 to 6 weeks after their diagnosis and were followed up for 1 to 12 months. In four children whose symptoms subsided completely within 2 to 10 weeks, MRI showed recanalization of the sigmoid sinus within 4 to 6 weeks after injury. In one child whose symptoms resolved after 6 months, sigmoid-sinus thrombosis persisted with the formation of collateral flow. We conclude that traumatic sigmoid-sinus thrombosis should be suspected when a child has persistent or delayed gait ataxia and vomiting after injury to the back of the head. Computed tomography characteristically demonstrated focal hyperdensity within the sigmoid sinus that we term the dense sigmoid-sinus sign. Because the sinus recanalized and the symptoms subsided in most children within 6 weeks, we conclude that prophylactic medical or surgical intervention is not indicated.