Petrous Carotid Artery Thrombosis in an Immunocompromised Patient Presenting With Mastoiditis, A Case Report

Objectives: The neurotologic literature commonly describes venous sinus thrombosis as a complication of mastoiditis. However, thrombosis of the internal carotid artery in the setting of mastoiditis is rarely described. We aim to document a case of carotid artery thrombosis in a patient presenting with mastoiditis. Methods: We describe this case and review relevant literature. Results: A renal transplant patient was transferred to our hospital with a left middle cerebral artery (MCA) infarct due to acute mastoiditis. Examination demonstrated middle ear effusion and radiologic workup confirmed mastoid infection adjacent to the site of arterial thrombosis. During cortical mastoidectomy and facial recess approach to the middle ear, the petrous carotid bone was found to be dehiscent with pneumatization of the petrous apex. Thrombosis was found to resolve following surgery, IV antibiotics and anticoagulation. Clinically, his focal neurological deficits improved. Proximity of the infectious process to an exposed petrous carotid artery supports the hypothesis that this patient's thrombus was a product of infectious spread and extra-luminal compression. Conclusion: To our knowledge, this is the first report of MCA infarction due to petrous ICA arterial thrombus in the setting of mastoid infection. The patient's immunocompromised state may have predisposed and contributed to the adverse outcome. We advocate for aggressive management of acute mastoiditis in the immunocompromised to prevent or manage complications (such as venous thrombophlebitis as well as ICA thrombus) as these patients don't show typical signs of infection and inflammation.