Massive traumatic subarachnoid hemorrhage mimicking aneurysmal subarachnoid hemorrhage.

Introduction: Massive traumatic subarachnoid hemorrhage (tSAH) is a rare but potentially life-threatening condition that can mimic the clinical presentation of aneurysmal subarachnoid hemorrhage (aSAH). The accurate differentiation between these two entities is crucial, as their management and prognoses significantly differ. Case presentation: We present a case of a 64-year-old male patient who presented to our emergency department after being involved in a motor vehicle collision. His radiological findings on a computed tomography (CT) scan were suggestive of aSAH based on its location, which showed massive SAH in bilateral sylvian fissures and the basal cisterns. There was no evidence of vasospasm. The patient later developed a stroke despite the use of Nimodipine. Conclusion: While traumatic subarachnoid hemorrhage mimicking aneurysmal subarachnoid hemorrhage is a recognized phenomenon, it is relatively uncommon. We present a case of massive tSAH complicated by a stroke with no evidence of aneurysm on cerebral angiogram, shedding light on the diagnostic challenges in differentiating tSAH from aSAH and emphasizing the importance of accurate diagnosis for appropriate management, in addition, we aim to remind the readers that trauma may be a cause for massive SAH and should prompt a medical SAH management plan.