Vagus nerve block as a diagnostic tool for VANCOUVER syndrome

Vagus Associated Neurogenic Cough Occurring due to Unilateral Vascular Encroachment of its Root (VANCOUVER) syndrome is a recently described neurovascular compression syndrome causing neurogenic cough due to a vascular compression of the vagus nerve at the brainstem. Some patients with VANCOUVER syndrome can lateralize the tickling sensation causing their irresistible cough; others cannot. For those who cannot lateralize their symptoms, a diagnostic vagus nerve block is required. This paper highlights the technique of percutaneous cervical vagus nerve block and its use in the diagnostic protocol for VANCOUVER syndrome.

The medical records of two patients who underwent a vagus nerve block were reviewed. The percutaneous cervical vagus nerve block was performed in the supine position, under ultrasound guidance with an in-plane needle technique as an outpatient procedure. Hemodynamic parameters and clinical effects were monitored.

Both patients were identified as potentially having VANCOUVER syndrome but could not lateralize their sensory symptoms. Each underwent unilateral vagus nerve block and returned for the contralateral procedure several weeks later. Both had temporary resolution of their cough following vagus nerve block ipsilateral to the intracranial vagus nerve compression but no effect following contralateral vagus nerve block. During the effects of the vagus nerve block, the patients had temporary vocal hoarseness, ipsilateral Horner syndrome, but no hemodynamic disturbances.

Vagus nerve block can confirm the diagnosis and lateralize the affected nerve in patients with VANCOUVER syndrome who cannot lateralize their symptoms. As the awareness of this syndrome increases, the procedure will become more common. An understanding of ultrasound-guided cervical anatomy is required for its safe use.