頸部回旋時の眼振から診断に至った椎骨動脈解離を伴う Bow hunter 症候群の1例

抄録

　Bow hunter's syndrome is a form of vertebrobasilar insufficiency in which cervical rotation causes mechanical occlusion or stenosis of the vertebrobasilar artery, resulting in various symptoms, including dizziness, vertigo, and/or syncope. We report a case of Bow hunter's syndrome in which cervical rotation caused dizziness and nystagmus.

　A 45-year-old woman presented to our hospital complaining of experiencing vertigo and nausea when twisting her neck. Nystagmus testing using Frenzel goggles revealed nystagmus during right cervical rotation. There was no hearing loss. Magnetic resonance imaging (MRI) showed no evidence of cerebral infarction; however, basi-parallel anatomical scanning MRI revealed arterial dissection in the left vertebral artery more peripherally than beyond the branching off of the posterior inferior cerebellar artery. Cervical ultrasonography and vertebral angiography confirmed that the patient experienced vertigo due to lack of blood flow in the proximal portion of the left vertebral artery when she rotated her neck 90 degrees to the right.

　Neurosurgeons at our institution performed neurosurgical C1-C2 posterior fixation, which led to complete resolution of her symptoms.

　The pathogenesis of Bow hunter's syndrome can take many distinct patterns, and the direction of cervical rotation does not always correspond to the side of the symptoms. To diagnose Bow hunter's syndrome, it is important to positively identify the onset of symptoms during cervical rotation and perform appropriate imaging studies.