Background <p>Life-threatening epistaxis as the initial manifestation of an internal carotid artery aneurysm is rare and diagnostically challenging, particularly in the absence of trauma or surgical history. Rupture into the sphenoid sinus may mimic gastrointestinal or neurological emergencies, delaying appropriate vascular intervention.</p> Case presentation <p>We report the case of a 71-year-old French Canadian woman with a history of hypertension and aspirin use who presented with recurrent syncope, melena, visual disturbances, and intermittent epistaxis. She was initially found to have profound anemia, bradyarrhythmia following nasal packing, and posterior circulation ischemia. Gastrointestinal investigations were unremarkable. Clinical deterioration prompted cardiac management with vasopressors and pacemaker placement. Following a massive epistaxis episode and transfusion, computed tomography angiography revealed a 7&#xa0;mm paraophthalmic internal carotid artery aneurysm projecting into an opacified sphenoid sinus. Cerebral angiography confirmed aneurysmal rupture, and endovascular coiling was successfully performed. The patient stabilized postintervention, with complete resolution of epistaxis and no neurologic or hemodynamic sequelae at discharge.</p> Conclusions <p>This case underscores the importance of considering massive epistaxis from a ruptured internal carotid artery aneurysm in patients presenting with melena, severe anemia, and a negative upper endoscopy, particularly when nasal bleeding is suspected. Posterior nasal packing may trigger bradycardia through reflex mechanisms that can be avoided. It should be removed early if associated with conduction abnormalities, as this improved our patient’s hemodynamics without necessitating further invasive solutions. Early vascular imaging and multidisciplinary coordination are crucial for the diagnosis and management of ruptured internal carotid artery aneurysms.</p>