PROSPECTIVE EVALUATION OF CLINICAL CHARACTERISTICS OF ORTHOSTATIC HYPOTENSION

Objective: To undertake a prospective study of the clinical characteri stics of orthostatic intolerant patients referred to the Mayo Autonomi c Reflex Laboratory with suspected orthostatic hypotension (OH). Desig n: Autonomic function tests were performed to quantify the severity of sudomotor, adrenergic, and cardiovagal failure and generate a composi te 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: T hree groups were defined by their response to a tilt study: group I, 9 0 patients with symptomatic OH, mean age, 63.6 years; group II, 60 pat ients 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. Furt her analysis was done on the 90 patients in group I. The most common s ymptoms were lightheadedness, weakness, impaired cognition, visual blu rring, 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. S ymptoms regressed significantly with CASS but not with the tilt grade. Conclusion: Patients with generalized autonomic failure have a recogni zable pattern of symptoms and aggravating factors that relate, albeit imperfectly, to the severity of autonomic failure.