Delayed Orthostatic Intolerance

Abstract

In seven patients who presented with lightheadedness, fatigue, "weakness," and sometimes syncope, blood pressure was found not to fall after standing for 3 to 4 minutes but to fall severely, frequently with syncope or presyncopal symptoms, after 13 to 30 minutes when measured every minute with an automatic device. This delayed orthostatic hypotension could be corrected with inflation of a pressure suit to 45 mm Hg. Its mechanism was further investigated with measurements of plasma catecholamines, plasma cortisol and aldosterone responses to corticotropin, and the effects of norepinephrine infusions on blood pressure and venous contractility. There was normal or excessive orthostatic norepinephrine release in all patients, evidence of impaired venous innervation in the legs in some, and various disorders in the other patients. Since therapeutic improvement in the orthostatic hypotension greatly reduced the symptoms, we concluded that orthostatic hypotension occurring after more than 10 minutes of standing is a potentially debilitating and often correctable disorder.

Treatment of postural tachycardia syndrome: a comparison of octreotide and midodrine

“…Subsequent chronic therapy confirmed a previous report indicating that octreotide ameliorated chronic fatigue in patients with OI and POTS [13]. We nevertheless encountered prevalent patient dissatisfaction during this study.…”

“…Many studies of drug efficacy in patients with POTS and OI have involved only a brief orthostatic stress and failed to measure standing time as has been previously recommended [13]. The limitations to this study must also be acknowledged.…”

“…tion when upright but nevertheless develop hypotension, syncope, nausea, palpitations or headaches with prolonged standing [13]. We included these patients in the present study in the category Orthostatic Intolerance (OI).…”

Schellong test in orthostatic dysregulation: a comparison with tilt-table testing

“…Fitzpatrick et al found that 60° upright tilt reproduced symptoms in 75% of 71 patients with unexplained syncope [21]. We favour our used protocol of the present study because supine resting for at least 30 minutes [22] and long duration of passive upright tilt [23] may increase the sensitivity of the test. Furthermore, by means of our protocol we were able to find orthostatic disorders in 83% of the symptomatic subjects, which suggests a high sensitivity of our method.…”

A Clinical, Physiology and Pharmacology Evaluation of Orthostatic Hypotension in the Elderly

“…If insufficient time is given for the patient to stand before rechecking blood pressure or if an intermediate reading is taken with the patient sitting down, a fall in blood pressure may not be demonstrated. In some patients a significant fall in blood pressure may be noted only after 10 minutes of standing [2].…”