Hypertensive Crisis Secondary to Afferent Baroreceptor Failure following Head and Neck Radiation

Introduction: Afferent baroreceptor failure is an uncommon cause of hypertension (HTN) that may result from carotid sinus injury. Characterized by labile HTN, postural blood pressure (BP) variation, orthostatic hypotension, and hypertensive crises, afferent baroreceptor failure is typically irreversible and often severely debilitating. Case Description: A 67-year-old woman with labile HTN, hypothyroidism, and oral squamous cell carcinoma treated with hemiglossectomy and high dose radiation to the head and neck in 2009 presented to our hospital with headaches, BP of 230/120, and stage 1 acute kidney injury. She reported paroxysms of headache, visual blurriness, nausea, and lightheadedness since at least 2015. Inpatient BP values ranged from 90/60 to 190/100, including orthostatic hypotension, supine HTN, and wide variations with use of short acting intravenous medications. Daily home medications included amlodipine 10 mg, hydrochlorothiazide (HCTZ) 25 mg, valsartan 320 mg, and pramipexole for restless leg syndrome, which was stopped. Renin activity was 0.8 ng/mL/h and aldosterone concentration was 6.1 ng/dL. CT angiography showed right renal artery stenosis estimated at 70%. Echocardiography demonstrated mild concentric hypertrophy. Amlodipine was continued, HCTZ was stopped, valsartan was reintroduced at a lower dose, and a clonidine patch was started. Serum creatinine returned to her baseline. Lower extremity compression stockings and an abdominal binder were applied and postural maneuver training was performed with physical therapy. BP logs demonstrated markedly fewer BP fluctuations and attenuation of BP extremes; the patient reported a reduction in paroxysmal symptoms ascribed to BP extremes. Discussion: Afferent baroreceptor failure from injury to carotid sinus neural structures may result in failure of counterregulatory signals during conditions that provoke extremes of blood pressure. Labile blood pressure, including paroxysms of HTN and symptomatic hypotension, can result in iterative end organ injury and disabling symptoms. Wider BP ranges are tolerated and avoidance of BP extremes is prioritized. Long-acting, central acting sympathetic blocking agents are often beneficial along with postural maneuver training, compressions stockings, and abdominal binders.