Glossopharyngeal neuralgia with syncope secondary to tumor. Treatment and pathophysiology

A patient with metastatic laryngeal carcinoma had glossopharyngeal neuralgia and syncope due to hypotension and bradycardia. Treatment of bradyarrhythmias failed to prevent hypotension. The administration of carbamazepine failed to prevent pain or syncope in this patient despite previous reports of success. Symptoms did resolve with intracranial section of the glossopharyngeal nerve and the upper two rootlets of the vagus. Plasma catecholamines were studied during a hypotensive episode. The values obtained demonstrated a suppressed sympathetic adrenergic neural response but an intact adrenomedullary response, suggesting that suppression of adrenergic vasoconstriction contributed to episodes of hypotension. The administration of intravenous atropine produced a transient increase in blood pressure suggesting that, in the presence of suppressed adrenergic vasoconstriction, cholinergic vasodilation may have contributed to the hypotension in this patient.