Intrapetrous Internal Carotid Artery Pseudoaneurysm Secondary to Malignant Otitis Externa: A Case Report

Malignant otitis externa (MOE) can rarely progress to skull base osteomyelitis (SBO) with catastrophic vascular complications. We describe a 68-year-old man with uncontrolled diabetes (HbA1c 9%) who presented with left otalgia, purulent otorrhea, and hearing loss. Initial workup showed CRP 23 mg/L, leukocytes 8,000/µL, and ear pus culture positive for Pseudomonas aeruginosa. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated MOE with temporal bone osteomyelitis. Despite prolonged intravenous antibiotics (imipenem, colistin) and topical ofloxacin, symptoms persisted. Three months later, he developed a headache, pulsatile tinnitus, and a pulsatile retro‑tympanic mass; MRI and 3D time-of-flight (TOF) angiography revealed progression of SBO with a pseudoaneurysm arising from the intrapetrous segment of the left internal carotid artery and ipsilateral sigmoid sinus septic thrombosis. Digital subtraction angiography was planned for definitive characterization and endovascular management, but the patient deteriorated rapidly and died of overwhelming septic shock before intervention. This case highlights that MOE can extend to involve the petrous internal carotid artery (ICA) and produce infected pseudoaneurysms; early vascular imaging [computed tomography angiography (CTA)/ magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) when indicated], aggressive antimicrobial therapy, and prompt multidisciplinary planning for endovascular or surgical intervention are essential to reduce morbidity and mortality.