To review the presentation, causes, and hemodynamic characteristics of patients with acquired afferent baroreflex failure. 

Damage to the vagus and/or glossopharyngeal nerves, or the nucleus of the solitary tract in the brainstem results in acquired afferent baroreflex failure, characterized by excessive blood pressure fluctuations.

Among 2,875 subjects in the NYU Patient Registry, we identified 17 patients (13 men, 4 women, aged 22-74 years at diagnosis) with acquired afferent baroreflex failure. Etiology included radiotherapy-induced damage to IX and X cranial nerves in the context of head and neck cancer (HPV-related squamous cell carcinoma or nasopharyngeal carcinoma) (n=11), surgical resection of brainstem neoplasia (n=2), paraganglioma (n=1), ganglioneuroma (n=1), carotid endarterectomy (n=1), or idiopathic (n=1). Presentation included labile blood pressure, blushing, headache, lightheadedness, and syncope. All patients had significant pressor and tachycardic responses to cognitive stress (e.g., mental calculations or discussing emotional or upsetting topics). Systolic blood pressure was very labile with maximum and minimum of 190±28.85 and 83.3±17.7 mmHg, respectively. All patients had orthostatic hypotension. Plasma norepinephrine levels in the supine position were 455± 254 pg/mL increasing to only 632±198 pg/ml after 10-mins of head-up tilt; and plasma vasopressin levels in the supine position were 0.65±0.21 pg/mL increasing to only 1.6±0.67 pg/ml after 10-mins of head-up tilt.