Subdural hygroma: results of treatment by ventriculo-abdominal shunt.

Subdural hygromas, which differ from acute and chronic subdural haematomas in clinical features and pathogenetic mechanism, can occur as isolated lesions or in association with ventricular dilatation and/or subarachnoid cysts which are mistaken for atrophy. On the basis of the postulate that these fluid accumulations might be related to a disturbance in CSF circulation, we treated them by ventriculoperitoneal CSF drainage. This was regarded as indicated only for children with symptoms of retardation and a distended ventricular system. Disappearance of the hygroma or the cortical cysts and ventricular dilatation was demonstrated in 9 of 14 children treated by ventriculo-abdominal shunt and in 4 of 7 less seriously affected untreated children. Clinical improvement came later than neuroradiological improvement, and was incomplete in a number of children. Although there are anamnestic factors with an unfavourable effect on development, the hygromas per se can cause cerebral dysfunction which is associated with their bifrontal localization. The principal symptoms are those of retardation in the development of verbal expression, leg motor function and manipulation.