title: Prospective evaluation of clinical characteristics of orthostatic hypotension.
abstract: OBJECTIVE
  To undertake a prospective study of the clinical characteristics of orthostatic intolerant patients referred to the Mayo Autonomic Reflex Laboratory with suspected orthostatic hypotension (OH).
  
  
  METHODS
  Autonomic function tests were performed to quantify the severity of sudomotor, adrenergic, and cardiovagal failure and generate a composite autonomic symptom score (CASS). CASS was related to a symptom score, which was derived from the frequency of orthostatic intolerance and syncope and the standing time until occurrence of symptoms.
  
  
  RESULTS
  Three groups were defined by their response to a tilt study: group I, 90 patients with symptomatic OH, mean age, 63.6 years; group II, 60 patients who had symptoms without OH, mean age, 48.9 years; and group III, 5 patients with asymptomatic OH, mean age, 68.0 years. Group I had a significantly higher CASS (P < 0.001) than did those without OH. Further analysis was done on the 90 patients in group I. The most common symptoms were lightheadedness, weakness, impaired cognition, visual blurring, tremulousness, and vertigo. The most common aggravating factors were prolonged standing, exercise, warming, and eating. Most patients (75%) could stand for less than 5 minutes before symptoms occurred. Symptoms regressed significantly with CASS but not with the tilt grade.
  
  
  CONCLUSIONS
  Patients with generalized autonomic failure have a recognizable pattern of symptoms and aggravating factors that relate, albeit imperfectly, to the severity of autonomic failure.
authors.affiliation: Autonomic Reflex Laboratory, Mayo Clinic Rochester, MN 55905, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Low
authors.forename: T L
authors.initials: TL
authors.lastname: Opfer-Gehrking
authors.forename: B R
authors.initials: BR
authors.lastname: McPhee
authors.forename: R D
authors.initials: RD
authors.lastname: Fealey
authors.forename: E E
authors.initials: EE
authors.lastname: Benarroch
authors.forename: C L
authors.initials: CL
authors.lastname: Willner
authors.forename: G A
authors.initials: GA
authors.lastname: Suarez
authors.forename: C J
authors.initials: CJ
authors.lastname: Proper
authors.forename: J A
authors.initials: JA
authors.lastname: Felten
authors.forename: C A
authors.initials: CA
authors.lastname: Huck
mesh_terms: D001341:Autonomic Nervous System / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D011187:Posture; D011446:Prospective Studies; D012720:Severity of Illness Index; D013997:Time Factors