虚血発症の非外傷性椎骨動脈解離の経過中に対側に無症候性解離性椎骨動脈瘤を合併した1症例

抄録

A 44-year-old man with a neck pain three weeks ago admitted to our hospital complaining of severe vertigo and gait disturbance. Magnetic resonance (MR) imaging revealed acute right lateral medullar infarction. MR angiography (MRA) revealed a narrowing of the right vertebral artery (VA) and MRA original image showed a double lumen in the right VA, indicating vertebral artery dissection (VAD). Conservative therapy was adopted and serial MRA or CT angiography (CTA) was followed. His symptom were improved gradually, but CTA obtained 16 days later revealed a new formation of left side (contralateral) VADA was observed. The VADA lesion was asymptomatic and restored naturally.

Bilateral occurrence of VAD at the same time of acute phase is generally considered rare, but may be more common than previously mentioned. The mechanism responsible for a contralateral VAD (VADA) after unilateral VAD is not obvious. Histopathological investigations reveals latent multiple dissecting lesions occurred bilateral intracranial VA recurrently. Changes in hemodynamic stress due to unilateral VAD are related to a dissecting aneurysmal formation on the lateral side. Even in case of unilateral VAD, frequent imaging monitoring (MRA or CTA) is important.