A 56 year old woman was referred to our hospital because of syncope during attacks of pain in the right side of her pharynx. She had a one year history of right glossopharyngeal neuralgia. Carbamazepine (200 mg daily) relieved the pain for about eight months, but as time went on, it became less effective and completely failed to control an exacerbation of the pain four months before admission. During neuralgia, ECG monitoring revealed asystole up to 26 seconds (upper panel) with syncope and seizures. Although the dose of carbamazepine was increased up to 400 mg daily, she continued to have spontaneous attacks of neuralgia and syncope associated with bradycardia and asystole. Therefore, a temporary cardiac pacemaker was needed to prevent syncopes before surgery. During the operation, right retromastoid craniectomy disclosed adhesions of the posterior inferior cerebellar artery (PICA) loop between cranial nerves IX and X (lower panel). Microvascular decompression was performed, followed by removal of the adhesions and freeing of the artery from these nerves. After the operation, the electrophysiologic study, carotid sinus massage, and head-up tilt testing showed no abnormal findings. No episodes of syncope or neuralgia occurred during a two month follow up postoperatively.

Glossopharyngeal neuralgia is an uncommon form of pain, but is well known as a cause of neurally mediated syncope. The afferent glossopharyngeal stimulus induces a vasovagal reflex, which causes bradycardia, cardiac arrest, and hypotension. In cases that are refractory to medical treatment, including carbamazepine, surgical treatment can relieve neuralgia and prevent syncope.