Orthostatic hypotension — ABIM Board MCQ

Correct answer: E — Diabetic autonomic neuropathy

The correct answer is diabetic autonomic neuropathy. He has a marked orthostatic blood-pressure decrease with only a minimal heart-rate increase, indicating impaired baroreflex-mediated sympathetic activation rather than an appropriate response to reduced intravascular volume. Long-standing diabetes, distal sensory neuropathy, and erectile dysfunction provide additional evidence of generalized diabetic neuropathy with autonomic involvement. Volume depletion usually causes a more substantial compensatory tachycardia. Paroxysmal supraventricular tachycardia produces episodic palpitations and marked tachycardia rather than persistent orthostatic hypotension with a nearly fixed pulse. Carotid sinus hypersensitivity is typically triggered by neck pressure or head movement. Primary adrenal insufficiency can cause hypotension but would more often be accompanied by findings such as weight loss, hyperpigmentation, hyponatremia, and hyperkalemia.

Reference: National Institute of Diabetes and Digestive and Kidney Diseases. Autonomic Neuropathy, section on heart rate and blood pressure. Last reviewed 2018. https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/nerve-damage-diabetic-neuropathies/autonomic-neuropathy