Posterior fossa subdural effusion due to head trauma.

We report 3 cases of posterior fossa subdural effusion resulting from head trauma, and we review 20 previously reported cases. All patients with the acute type presented with progressive deterioration of consciousness associated with stiff neck, seizure, and dyspnea (apnea). By contrast, in the subacute or chronic type, persistent headache, multiple cranial nerve pareses, and ataxia were characteristic. Occipital bone fracture was common in the acute type, and supratentorial subdural effusion was more frequently associated with the subacute or chronic type. Evacuation of the subdural fluid collection through a burr hole is the most common and effective treatment, but subdural-peritoneal shunting or closed drainage of the subdural fluid collection may be necessary. The prognosis of posterior fossa subdural effusion after head trauma is relatively good.