Spontaneous Extracranial Internal Carotid Artery Dissection Solely Presenting with Sudden Onset Pulsatile Tinnitus

Spontaneous internal carotid artery dissection is a rare condition that generally affects middle-aged individuals. Most cases of reported spontaneous internal carotid artery dissections are unilateral, but approximately 10%-20% involve bilateral internal carotid arteries. Spontaneous internal carotid artery dissection generally presents with neck pain, ischemic cerebral symptoms, and/or Horner's syndrome. Pulsatile tinnitus is present in around 5%-10% of spontaneous internal carotid artery dissection cases. However, this is generally accompanied by other major internal carotid artery dissection symptoms. Herein, we report a case of bilateral spontaneous internal carotid artery dissection that presented with unilateral pulsatile tinnitus of sudden onset as an isolated symptom. An otherwise healthy 50-year-old man visited a neurosurgical clinic complaining of right temporal pulsatile tinnitus that had begun 1 day prior. In addition to tinnitus, a thorough symptom interview revealed mild heavy-headedness. Magnetic resonance angiography showed bilateral extracranial internal carotid artery dissections and severe stenosis of the true lumen of the right internal carotid artery. No cerebral ischemic lesions were observed. Administration of 5 mg/day amlodipine and 100 mg/day aspirin was initiated. Following the 9th day after onset, the pulsatile tinnitus gradually improved. Around the 40th day after onset, the pulsatile tinnitus disappeared, and magnetic resonance angiography showed an improvement of the right internal carotid artery stenosis. Magnetic resonance angiographies at 5 and 9 months after onset revealed complete disappearance of the false lumen and slight stenosis of the right internal carotid artery at the entrance of the carotid canal. This case suggests that the sudden onset of isolated unilateral pulsatile tinnitus can be a clue to the diagnosis of spontaneous internal carotid artery dissection.