Acute subdural hematoma caused by ruptured cerebral aneurysms: diagnostic and therapeutic pitfalls.

On rare occasions, rupture of a cerebral aneurysm causes acute subdural hematoma (SDH) in addition to subarachnoid hemorrhage (SAH). The frequency of SDH resulting from aneurysmal rupture is summarized, and its clinical and radiological characteristics, as well as potential pitfalls in the diagnosis and the management of this life-threatening condition are described. Among 641 patients with nontraumatic SAH treated between 1992 and 2000, 12 patients (1.9%) presented with SDH due to aneurysmal rupture. The SAH grade on admission was grade II in one patient, grade IV in three patients, and grade V in eight patients. Four underwent both hematoma evacuation and clipping of the aneurysm, four underwent hematoma evacuation alone, and the other four patients were treated conservatively. The outcome was good recovery in two patients, severe disability in one patient, and death in nine patients. Patients with a good outcome had a better SAH grade on admission, smaller midline shift, and smaller SDH volume on the initial CT scan, and they had been treated by both SDH evacuation and clipping of the aneurysm. Emergency one-stage operations may be beneficial for aneurysmal SDH patients who are in good SAH grade, or those who are in poor SAH grade but show some neurological recovery after resuscitation. It should also be mentioned that there are cases of aneurysmal SDH without recognizable SAH on the CT scans, and that a case of aneurysmal SDH may present as a case of 'head trauma' after an accident, because of the disturbance of consciousness resulting from aneurysmal rupture.