Radiation-Induced Baroreflex Dysfunction: A Rare Case of Severe Orthostatic Hypotension.

Baroreflex failure is an under-recognized and often overlooked cause of orthostatic hypotension, particularly following head and neck radiation therapy. We present an 88-year-old man who developed recurrent falls and a distinctive pattern of supine hypertension with systolic pressures reaching 235 mmHg and orthostatic hypotension as low as 66/44 mmHg three weeks after completing treatment for basal cell carcinoma. A comprehensive workup, including brain imaging, telemetry, serum catecholamines, thyroid function, and immunofixation electrophoresis, excluded structural, endocrine, and infiltrative causes of autonomic dysfunction. Radiation-induced baroreflex failure was inferred clinically based on pronounced positional blood pressure (BP) variability, lack of reciprocal heart rate changes, and the temporal relationship to recent therapy. Treatment with droxidopa, compression therapy, and a carefully titrated antihypertensive regimen led to improvement in orthostatic tolerance. Titration prioritized relief of symptomatic hypotension with droxidopa before addressing nocturnal hypertension, which was managed non-reactively using low-dose amlodipine. The patient remained stable throughout the 10-month follow-up with sustained symptom improvement. This case underscores the importance of recognizing radiation as a potential cause of baroreflex failure in patients with significant polyvascular disease, expanding the spectrum of presentations to include earlier onset than historically reported.