A case of bow hunter’s syndrome due to bilateral extracranial vertebral artery dissection in the craniovertebral junction caused by neck rotation

Abstract

A 41-year-old man was transferred to our hospital because of sudden nuchal pain just after habitual head rotation, followed by dizziness, speech disturbance, and weakness of right half body. On admission, he had mild consciousness disturbance, right homonymous hemianopsia, dysarthria, right hemiparesis, and cerebellar ataxia in the left upper and lower limbs. Brain MRI showed multiple high intensity lesions in the left cerebellum and left medial thalamus on diffusion-weighted image. Cervical MRA and CT angiography showed right extracranial vertebral artery dissection. We diagnosed him artery-to-artery embolisms due to vertebral artery dissection. Vertebral angiography revealed interruption in-flow of the right vertebral artery on head rotation to the left side. He complained of new nuchal pain on head rotation to the right side under examination. Stenotic changes and flow interruption on head rotation to the right side in the left vertebral artery was newly documented on the angiography. Subsequently, he complained of transient dizziness. On the following day, we diagnosed bow hunter’s syndrome due to bilateral extracranial vertebral artery dissection based on the detection of additional left vertebral artery dissection on MRA. Treatment with antiplatelet and cervical hard collar fixation improved his symptoms immediately and did not lead to any ischemic events. We should pay close attention to the incidence of new vertebral artery dissection caused by neck rotation when we perform an angiography to investigate extracranial vertebral artery dissection in the craniovertebral junction.