To identify physiologic differences in young PoTS patients with and without headache provoked during tilt-table testing, in order to further understand potential pathophysiologic mechanisms for orthostatic headache.

In patients undergoing autonomic evaluation, the autonomic reflex screen (ARS) is commonly used. Testing includes the Valsalva maneuver, heart rate response to deep breathing (HRDB), and head-up tilt table (HUTT). In addition to orthostatic tachycardia, orthostatic headache is commonly noted during HUTT and is often reported by patients with PoTS.

In this retrospective review, a database of patients diagnosed with PoTS based on testing at the University of Utah Autonomic Physiology Laboratory was reviewed. Patients aged 19 years or younger were identified and their ARS data were reviewed. Blood pressure measurements during Valsalva, Valsalva ratio, HRDB, and pulse recovery time were recorded. ARS reports were reviewed to identify patients who reported new or worsening headache during HUTT. ARS parameters were then compared between headache and non-headache groups and results compared using unpaired t-test.

31 patients aged 11 to 19 (median 16.5 years) were included, of which 22 (73.3%) were female. Of these patients, 17 (55%) had a documented history of headache. New or worsening headache during HUTT was reported by 9 patients (29%). Compared to those without headache during HUTT, patients who reported headache had decreased phase IV (16.4 vs 26.8 mmHg, p=0.002), longer pulse recovery time (4.60 vs 2.28 sec, p=0.023), and less narrowing of baseline pulse pressure (36.3% vs 49.3%, p=0.014). There were not significant differences in other Valsalva phases, adrenergic baroreflex sensitivity, Valsalva ratio, or HRDB.

There are physiologic differences on autonomic reflex screen between patients with and without orthostatic headache, particularly in parameters representing cardiovascular adrenergic responses during Valsalva. These findings may suggest that altered cardiovascular adrenergic function contributes to orthostatic headache in patients with PoTS.