Subclavian steal syndrome: neurotological manifestations

The subclavian steal syndrome is characterized by a subclavian artery stenosis located proximal to the origin of the vertebral artery. In this case, the subclavian artery steals reverse-flow blood from the vertebrobasilar artery circulation to supply the arm during exertion, resulting in vertebrobasilar insufficiency. As the vertebrobasilar arterial system feeds both the peripheral and central auditory and vestibular systems, in subclavian steal syndrome, neurotological symptoms are expected because of the vertebrobasilar insufficiency. In this report, we describe three patients suffering from subclavian steal syndrome, who presented with isolated dizziness, recurrent vertigo, hearing loss and tinnitus. In two of the three cases, a positional nystagmus was detected, which was vertical in two. Abnormal saccades were documented in one, and the auditory brainstem responses were pathological in all three patients; the caloric response was reduced in only one case. Upon magnetic resonance imaging, ischaemic lesions were observed in two patients, in the brainstem and in the hemispheres, respectively. These findings suggest that the central auditory and vestibular system is more likely to be involved in the pathogenesis of neurotological symptoms in subclavian steal syndrome. Patiehts complaining of numbness of the upper arm and isolated neurotological symptoms should be thoroughly examined for subclavian steal syndrome. Furthermore, regular follow-up must be undertaken in order to prevent other neurological deficits in the vertebrobasilar arterial territory.