Abstract P343: Utility of Autonomic Testing for the Diagnosis of Neurogenic Orthostatic Hypotension and Subsequent Management With Droxidopa

Abstract

A 62-year-old man with a history of Hodgkin lymphoma, lupus, type 2 diabetes mellitus, neuropathy, hypercholesterolemia, hypothyroidism, and orthostatic hypotension who was taking gabapentin, saxagliptin, pravastatin, levothyroxine sodium, omeprazole, prednisone, midodrine, and fludrocortisone was evaluated for syncope, collapse, and fluctuating blood pressure (BP). He reported a 2-year history of syncope, with progressive worsening over a 3-month period. Initially, his episodes of syncope were preceded by dizziness and nausea, but began to occur without warning. He also reported a 5-year history of orthostatic hypotension, with supine BP of 100/60 mmHg and standing BP of 50-60/40 mmHg. Treatment with midodrine (10 mg three times daily) and fludrocortisone (0.1 mg twice daily [BID]) did not relieve his symptoms. Initial cardiac evaluation revealed a systolic murmur, but was otherwise unremarkable. Autonomic function tests, including continuous electrocardiography, BP and heart rate monitoring at 2-min intervals, and transcranial Doppler, were performed in the supine and 80° head-up tilt positions. A BP drop from 112/68 mmHg to 76/60 mmHg occurred within 2 min of tilt, accompanied by dizziness and presyncope. Heart rate with deep breathing revealed a depressed baseline autonomic tone, and a Valsalva maneuver test showed a depressed Valsalva response (Valsalva ratio: 1.15). Taken together, these results indicated a diagnosis of neurogenic orthostatic hypotension (nOH). Treatment with droxidopa (100 mg BID) was initiated; this dose was titrated to 100 mg once daily due to hypertension, for which, a nitroglycerin patch (0.2 mg nightly) was prescribed. All other medications were continued. Treatment with droxidopa significantly improved his symptoms; he no longer loses consciousness upon positional change, but still experiences some symptoms of presyncope (eg, slight lightheadedness, dizziness). This has allowed greater integration into activities of daily living and a less strenuous routine for the patient and his caretakers . In conclusion, autonomic function testing in this patient effectively led to a timely diagnosis of nOH which, in turn, allowed for implementation of appropriate pharmacologic intervention to manage symptoms.