title: Syncope in complex regional pain syndrome.
abstract: BACKGROUND
  Complex regional pain syndrome (CRPS) is a debilitating pain syndrome characterized clinically by severe pain along with signs and symptoms of autonomic dysfunction. Presyncope and syncope are common in these patients. The purpose of this study was to investigate the cause of these symptoms in these patients.
  
  
  OBJECTIVE
  Patients with CRPS are more prone to presyncope and syncope as evidenced by head-up tilt table testing (HUTT).
  
  
  METHODS
  Patients with CRPS underwent a complete cardiac evaluation that included a 12-lead electrocardiogram, 2-dimensional echocardiography, 24-hour Holter monitoring, and HUTT.
  
  
  RESULTS
  Seventy-four patients with CRPS were evaluated. Eight CRPS patients (10%) could not complete a HUTT due to pain. Of the 66 CRPS patients who completed a HUTT, 15 (37.9%) reported pretest symptoms of presyncope or syncope. Twenty-eight CRPS patients (42.4%) had a positive HUTT. CRPS patients with lower limb involvement were more likely to have vasovagal syncope or orthostasis on HUTT than those with upper extremity or total body involvement (12 of 18 [67%] vs 16 of 48 [33%]; P = 0.015).
  
  
  CONCLUSIONS
  Syncope is common in patients with CRPS, especially with lower limb involvement. Autonomic dysregulation of the lower extremities leads to impaired sympathetic vasoconstriction and venous pooling, which can predispose these patients to syncope. Physician awareness of this syndrome will lead to improved recognition and treatment of their symptoms of presyncope or syncope.
authors.affiliation: Department of Cardiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA. doctorjay21074@yahoo.com
authors.forename: Jason A
authors.initials: JA
authors.lastname: Smith
authors.forename: Dean G
authors.initials: DG
authors.lastname: Karalis
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Rosso
authors.forename: John R
authors.initials: JR
authors.lastname: Grothusen
authors.forename: Scott E
authors.initials: SE
authors.lastname: Hessen
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schwartzman
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D016009:Chi-Square Distribution; D020918:Complex Regional Pain Syndromes / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D004452:Echocardiography; D004562:Electrocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010414:Pennsylvania / Q000453:epidemiology; D011237:Predictive Value of Tests; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D013575:Syncope / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D018667:Tilt-Table Test