Recurrent extracranial internal carotid artery vasospasm diagnosed by serial magnetic resonance angiography and superselective transarterial injection of a calcium channel blocker

Recurrent vasospasm of the extracranial internal carotid artery (ICA) is extremely rare, and optimal management is unclear. A 25-year-old woman developed transient dysarthria and left-sided hemiparesis. Initial magnetic resonance (MR) imaging showed spotty acute infarction in the right temporal lobe, and MR angiography revealed right ICA occlusion. ICA occlusion was spontaneously resolved within 6 days of its onset, whereas transient left ICA narrowing was evident at 12 days. Because recurrent occlusion of the right ICA occurred at 14 days when the contralateral ICA was still narrowed, we attempted a local intra-arterial injection of a calcium channel blocker based on the diagnosis of recurrent extracranial ICA vasospasm. The local injection of 1 mg of nicardipine partially dilated the affected ICA, which confirmed the diagnosis of vasospasm. After the introduction of oral medication with benidipine hydrochloride, bilateral ICA vasospasm was completely resolved 23 days after its onset, as shown by MR angiography. In conclusion, we recommend intensive radiologic follow-up at the acute stage and therapeutic catheter angiography when the bilateral lesion is evident because bilateral occlusion of the ICA could lead to a catastrophic condition.