Orthostatic intolerance

Orthostatic intolerance (OI) is the inability to correctly regulate blood pressure, cerebral blood flow and consciousness when upright, usually when standing, but it can also occur when sitting. If irregular blood pressure and heart rate initiate while in a supine position (lying down, faceup), then officially it is not OI.

Prevalence

Orthostatic intolerance is a common dysfunction in ME/CFS. Estimates of the rate of orthostatic intolerance in Chronic Fatigue Syndrome and myalgic encephalomyelitis patients vary widely, with estimates as low as 50% to as high as 97% of patients.

Orthostatic intolerance is also commonly associated with fibromyalgia.

Testing

Orthostatic intolerance can be diagnosed by a tilt table test, although a tilt table test isn't required. It is part of the Institute of Medicine report's proposed diagnostic criteria for Systemic Exertion Intolerance Disease.

The NASA 10-minute Lean Test is a variant of a test used by NASA researchers to test for orthostatic intolerance following space flight. The adaption for ME/CFS patients was developed by Dr. Lucinda Bateman, which she recommends all ME/CFS and fibromyalgia patients undergo to assess for orthostatic intolerance. The NASA 10-minute Lean Test in less taxing on the patient and can be done in any physician's office. Instructions are available for printout for both healthcare providers and patients.

Symptom recognition

• In the London criteria, orthostatic intolerance is mentioned under the criteria of periods of impaired circulation compatible with autonomic dysfunction.

Type of orthostatic intolerance

Postural orthostatic tachycardia syndrome

Postural orthostatic tachycardia syndrome (POTS) is one of a group of disorders that have orthostatic intolerance (OI) as their primary symptom. The primary symptom of OI is lightheadedness or fainting. In POTS, the lightheadedness or fainting is also accompanied by a rapid increase in heartbeat of more than 30 beats per minute, or a heart rate that exceeds 120 beats per minute, within 10 minutes of rising.

Orthostatic hypotension

Also called postural hypotension, it is a form of sudden low blood pressure that occurs upon standing. It can often cause dizziness. it is defined as a fall in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg when a person assumes a standing position.

Neurally mediated hypotension

Also called neurally mediate syncope, in NMH, peripheral vasodilation causes blood to pool in the extremities. It is associated with a decrease in blood pressure, and a slow or lowered heart rate upon standing.

Notable studies

• 2016, Orthostatic Changes in Hemodynamics and Cardiovascular Biomarkers in Dysautonomic Patients
• 2015, Intravenous Hydration for Management of Medication-Resistant Orthostatic Intolerance in Adolescents and Young Adults
• 2000, The Roles of Orthostatic Hypotension, Orthostatic Tachycardia, and Subnormal Erythrocyte Volume in the Pathogenesis of the Chronic Fatigue Syndrome
• 2000, Orthostatic Intolerance: A Review with Application to the Chronic Fatigue Syndrome
• 1999, Orthostatic intolerance in the chronic fatigue syndrome

Talks & interviews

• 2016, "Remaining Upright: Approach to Orthostatic Intolerance" - Melissa Cortes
• 2010, "Mangaging Orthostatic Intolerance" - Peter Rowe

Learn more

• 2016, Remaining Upright: Approach to Orthostatic Intolerance (Bateman Horne Center)
• 2016, NIH gives $246,000 for study of oral rehydration in ME/CFS patients with orthostatic intolerance
• 2015, Orthostatic Intolerance

See Also

• Tilt table test
• Dizziness
• Neurally mediated hypotension
• Postural orthostatic tachycardia

orthostatic intolerance (OI) - The development of symptoms when standing upright, where symptoms are relieved upon reclining. Patients with orthostatic intolerance have trouble remaining upright for more than a few seconds or a few minutes, depending upon severity. In severe orthostatic intolerance, patients may not be able to sit upright in bed. Orthostatic intolerance is often a sign of dysautonomia. There are different types of orthostatic intolerance, including postural orthostatic tachycardia syndrome (POTS).

orthostatic intolerance (OI) - The development of symptoms when standing upright, where symptoms are relieved upon reclining. Patients with orthostatic intolerance have trouble remaining upright for more than a few seconds or a few minutes, depending upon severity. In severe orthostatic intolerance, patients may not be able to sit upright in bed. Orthostatic intolerance is often a sign of dysautonomia. There are different types of orthostatic intolerance, including postural orthostatic tachycardia syndrome (POTS).

cerebral blood flow (CBF) - the amount of blood that goes through the arterial tree in the brain in a given amount of time

heart rate (HR) - the number of times the heart beats within a certain time period, usually a minute

supine lying on the back or with the face upward

postural orthostatic tachycardia syndrome (POTS) - A form of orthostatic intolerance where the cardinal symptom is excessive tachycardia due to changing position (e.g. from lying down to sitting up).

postural orthostatic tachycardia syndrome (POTS) - A form of orthostatic intolerance where the cardinal symptom is excessive tachycardia due to changing position (e.g. from lying down to sitting up).

lightheadedness the condition of being dizzy or on the verge of fainting

orthostatic intolerance (OI) - The development of symptoms when standing upright, where symptoms are relieved upon reclining. Patients with orthostatic intolerance have trouble remaining upright for more than a few seconds or a few minutes, depending upon severity. In severe orthostatic intolerance, patients may not be able to sit upright in bed. Orthostatic intolerance is often a sign of dysautonomia. There are different types of orthostatic intolerance, including postural orthostatic tachycardia syndrome (POTS).

tachycardia An unusually rapid heart beat. Can be caused by exercise or illness. A symptom of postural orthostatic tachycardia syndrome (POTS). (Learn more: www.heart.org)