Treatment of a symptomatic posterior fossa subdural effusion in a child

We describe the first observation of a child with a posterior fossa subdura l effusion with secondary hydrocephalus and tonsillar herniation. We diagno sed this entity in a 14-month-old girl with no history of trauma or coagula tion disorder. The patient presented in our emergency department with opist hotonus and raised intracranial pressure resulting from supratentorial hydr ocephalus. An emergency ventriculo-peritoneal shunt was placed, which resol ved the symptoms only temporarily. Eventually external drainage of the subd ural fluid was performed. The collection gradually disappeared, and both th e external subdural shunt and the ventriculo-peritoneal shunt were removed. The patient made a complete neurological recovery. We review the physiopat hology and treatment of subdural effusions in general, and propose some gui delines for the management of symptomatic effusions occurring in the poster ior fossa in particular.