ABSTRACT

Bilateral acute subdural hematoma is an uncommon presentation of the rupture of an intracranial aneurysm. We report one case of the rupture of posterior communicating cerebral artery aneurysm presented with bilateral acute subdural hematoma. Such a patient requires changes in routine preoperative management.

Keywords: Bilateral subdural hematoma – aneurysm rupture

INTRODUCTION

Bilateral spontaneous acute subdural hematoma is an uncommon manifestation of the rupture of a cerebral aneurysm. Aneurysms of the internal carotid artery and middle cerebral artery are more commonly associated with the presentation of subdural hematoma (3, 8, 10). Bilateral acute subdural hematoma is very rare. We don’t find any same cases reported in the literature. We report one case of bihemispheric acute subdural hematomas secondary to the rupture of an left posterior communicating artery aneurysm.
The radiologic findings and possible mechanisms of this hemorrhage are discussed.

CASE REPORT

A 44-year-old woman presented with a sudden consciousness during her job. The clinical exam was revealed a deep coma (GSC=5) and right anisocoria.
An emergency CT showed a minime bilateral acute subdural hematoma at the frontal convexity, without significant mass effect. Also there was not clearly evidence of blood in the arachnoid’s space. MRI confirmed the diagnostic of bihemispheric acute subdural hematomas.
Left carotid angiography showed an aneurysm of the posterior communicating cerebral artery.

DISCUSSION

Although rupture of cerebral aneurysms usually results in subarahnoid hemorrhage (about 60%), intracerebral hematoma is often seen in 30-40% and intraventricular hematoma in 12-17% (1, 3, 4, 6). The incidence of spontaneous acute subdural hematoma due to aneurysm rupture varies from 0.5 % to 7.9% (3, 4, 6, 8).

In our case we were perplexed whether this bleeding was spontaneous or secondary to the rupture of aneurysm, and we could not deny the possibility of the ruptured aneurysm, because of the bilateral of the bleeding. These lesions are usually unilateral, bilateral hematoma is very rare. We discuss the relationships of aneurysm and subdural hematoma.

Different mechanisms have been proposed to explain the causation of acute subdural hematoma after the rupture of aneurysm:
– One mechanism is that aneurysm adherent to the arachnoid’s may bleed directly into the subdural space when the arachnoid’s tear occurs after aneurysm rupture.
– Another mechanism may be the stream of blood may rupture through the arachnoid’s at some distant weak point. Lastly, the subdural hematoma may develop secondary to the decompression of intracerebral hematoma into the subdural space following disruption of the covering the cerebral cortex.

Acute subdural hematoma had been described in association with aneurysms at almost all the branches of intracranial arteries. Fox analyzed the world literature and found 56 reports containing 146 cases of subdural hematoma there were published between 1895 and 1978. The commonest aneurysm associated with subdural hematoma is internal carotid artery aneurysm, followed by middle cerebral artery aneurysm.

About 80% of the cases of subdural hematoma due to the rupture of cerebral aneurysm reported in the literature were seen in females.

CONCLUSION

An acute subdural hematoma in the absence of head trauma requires further neuro-radiological investigation to define its possible cause. If the patient is stable enough to allow further investigations before craniotomy, then angiographic study to define the vascular lesion must be considered. However, in the face of rapid clinical deterioration, an emergency craniotomy for subdural evacuation should be performed before further investigations (6, 12).

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