Publication:

Uncommon cause of vertigo: Bow Hunter syndrome

Rotational vertebral artery syndrome, recognized as Bow Hunter syndrome (BHS), was a rare but potentially debilitating condition characterized with triggered vertigo, dizziness, and syncope. It results from dynamic vertebral artery (VA) stenosis due by compression from adjacent anatomical structures during specific neck movements. It may be easily overlooked even with the use of advanced imaging techniques because its symptoms closely resemble other episodic vestibular disorders, including benign paroxysmal positional vertigo. However, BHS may cause posterior circulation stroke. The only definitive diagnostic method for BHS is provocative neck movement testing, with provocative digital subtraction angiography (DSA) as the gold standard. A 61-year-old female had vertigo, dizziness, and presyncope which was triggered by rotating her neck to the left. Angiographic head-to-neck CT showed cervical spondylosis with osteophytes at C5-C6 vertebral level without any blood vessel abnormalities. Conventional DSA discovered hypoplastic right VA. Following provocative neck movement to the left, significant stenosis of left VA was detected. She was advised to immobilized her neck and consulted to neurosurgeons for the consideration of surgical decompression. Although rare, BHS should be considered as a potential cause of vertigo. Normal vascular assessment from ancillary tests did not rule out BHS. Recognizing BHS was crucial for its comprehensive evaluation of provocative physical examination to provocative DSA. Treatment options include neck immobilization, anticoagulation therapy, and surgical intervention, with or without dynamic intraoperative angiography.