title: Hyperadrenergic postural tachycardia syndrome in mast cell activation disorders.
abstract: Postural tachycardia syndrome (POTS) is a disabling condition that commonly affects otherwise normal young females. Because these patients can present with a flushing disorder, we hypothesized that mast cell activation (MCA) can contribute to its pathogenesis. Here we describe POTS patients with MCA (MCA+POTS), diagnosed by episodes of flushing and abnormal increases in urine methylhistamine, and compared them to POTS patients with episodic flushing but normal urine methylhistamine and to normal healthy age-matched female controls. MCA+POTS patients were characterized by episodes of flushing, shortness of breath, headache, lightheadedness, excessive diuresis, and gastrointestinal symptoms such as diarrhea, nausea, and vomiting. Triggering events include long-term standing, exercise, premenstrual cycle, meals, and sexual intercourse. In addition, patients were disabled by orthostatic intolerance and a characteristic hyperadrenergic response to posture, with orthostatic tachycardia (from 79+/-4 to 114+/-6 bpm), increased systolic blood pressure on standing (from 117+/-5 to 126+/-7 mm Hg versus no change in POTS controls), increased systolic blood pressure at the end of phase II of the Valsalva maneuver (157+/-12 versus 117+/-9 in normal controls and 119+/-7 mm Hg in POTS; P=0.048), and an exaggerated phase IV blood pressure overshoot (50+/-10 versus 17+/-3 mm Hg in normal controls; P<0.05). In conclusion, MCA should be considered in patients with POTS presenting with flushing. These patients often present with a typical hyperadrenergic response, but beta-blockers should be used with great caution, if at all, and treatment directed against mast cell mediators may be required.
authors.affiliation: Division of Clinical Pharmacology, Department of Medicine and Pharmacology, and the Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, Tenn 37212, USA.
authors.forename: Cyndya
authors.initials: C
authors.lastname: Shibao
authors.forename: Carmen
authors.initials: C
authors.lastname: Arzubiaga
authors.forename: L Jackson
authors.initials: LJ
authors.lastname: Roberts
authors.forename: Satish
authors.initials: S
authors.lastname: Raj
authors.forename: Bonnie
authors.initials: B
authors.lastname: Black
authors.forename: Paul
authors.initials: P
authors.lastname: Harris
authors.forename: Italo
authors.initials: I
authors.lastname: Biaggioni
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects / Q000627:therapeutic use; D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006634:Histamine H1 Antagonists / Q000627:therapeutic use; D006635:Histamine H2 Antagonists / Q000627:therapeutic use; D006801:Humans; D007024:Hypotension, Orthostatic / Q000188:drug therapy / Q000503:physiopathology*; D008407:Mast Cells; D008750:Methyldopa / Q000627:therapeutic use; D013565:Sympatholytics / Q000627:therapeutic use; D013577:Syndrome; D013610:Tachycardia / Q000188:drug therapy / Q000503:physiopathology*
chemical_list: D000319:Adrenergic beta-Antagonists; D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D013565:Sympatholytics; D008750:Methyldopa