Convexal subarachnoid hemorrhage due to infective endocarditis: a rare forensic autopsy case

Infective endocarditis (IE) is a life-threatening disease characterized by various systemic complications, including neurological manifestations. Although subarachnoid hemorrhage (SAH) is a rare complication of IE, particularly in the absence of aneurysms, the underlying pathophysiological mechanisms remain poorly understood. We report a rare autopsy of a man in his 50s who suddenly died without medical intervention. Postmortem imaging and autopsy showed bilateral convexal SAH (cSAH). Histological examination confirmed IE with gram-positive bacterial colonies in the mitral valve and septic embolization in several organs. In the subarachnoid hemorrhage, gram-positive bacterial colonies and multiple vessels with intense neutrophilic infiltration were observed. These findings provide rare pathological evidence that cSAH can be caused by septic emboli-induced vascular destruction, independent of aneurysmal rupture. This case highlights the need for clinicians and forensic pathologists to consider IE in unexplained deaths with elevated inflammatory marker levels and SAH, even when no cerebral aneurysms are detected. Prompt diagnosis and treatment could be lifesaving in similar cases. To the best of our knowledge, this is an exceptionally rare case report documenting histological confirmation of non-aneurysmal SAH secondary to IE in a forensic autopsy.