Recurrent embolic cerebellar infarction due to bow hunter's syndrome of the non-dominant vertebral artery.

We describe a rare presentation of bow hunter's syndrome (BHS) involving the non-dominant vertebral artery (VA), leading to recurrent embolic cerebellar infarction. A male in his mid-70s presented with sudden-onset immobilising vertigo. MRI revealed acute cerebellar ischaemia with occlusion of the left superior cerebellar artery. Dynamic duplex ultrasonography and angiography revealed an occlusion of the left VA in the V2 segment during head rotation to the left due to an osteophyte protruding from the C3/C4 vertebrae. The patient was diagnosed with embolic strokes due to compression of the left, non-dominant VA. He was treated with osteophyte resection and anterior cervical discectomy and fusion. BHS is the medical syndrome associated with the compression of the VA induced by movement or rotation of the head, resulting in symptoms of vertebrobasilar insufficiency or stroke. As a rare cause of stroke, it can be diagnosed through dynamic duplex ultrasound and angiography with head rotation. This case is an important addition to the literature because it highlights three key learning points: (1) BHS is a frequently underdiagnosed and underreported cause of transient ischaemic attack, stroke, disability and death; (2) early diagnosis and intervention can prevent devastating outcomes; (3) BHS can cause embolic stroke even from the non-dominant VA.