Neurally mediated hypotension

Neurally mediated hypotension or NMH is an abnormality in regulating blood pressure experienced when the person is upright. NNH causes a drop of 20–25 mm Hg in systolic blood pressure when a person is standing still compared to lying down. NMH is a form of chronic orthostatic intolerance.

Signs and symptoms

Symptoms may include lightheadedness, dizziness, pressure-like left-side chest pain, visual changes and at times, loss of consciousness (blackouts), weakness, more pain when hit by something, slower speech or slowed verbal response, pallor, an immediate urge to lie down and syncope (fainting).

Blood pressure readings taken lying down and when upright can be compared to assess for a drop in systolic blood pressure. For example, a blood pressure of 130/85 mm Hg may change to 100/85 mm Hg when the person stands, and does not return to normal.

Explanation

According to Blood Pressure Updates, neurally mediated hypotension "is a complication that occurs due to unnatural reflex action between the brain and heart, though they are structurally normal. Neurally mediated hypotension is also called fainting reflex, or vasodepressor syncope or neurocardiogenic syncope or autonomic dysfunction or vaso-vagal reflex. Syncope is the formal medical term used for fainting."

ME/CFS

Neurally mediated hypotension has been found in ME/CFS patients:

• 1998, Neurally mediated hypotension and chronic fatigue syndrome
• 1995, The relationship between neurally mediated hypotension and the chronic fatigue syndrome

See also

• Orthostatic intolerance (OI)
• Postural orthostatic tachycardia syndrome (POTS)
• Autonomic nervous system
• Dizziness
• Hypotension
• Tilt table test

Learn more

• What is Neurally Mediated Hypotension? - The Orthostatic Intolerance Center

the condition of being dizzy or on the verge of fainting

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

syncope A medical term for fainting. A loss of consciousness resulting from insufficient blood flow to the brain.

See myalgic encephalomyelitis.

See chronic fatigue syndrome.

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).

See postural orthostatic tachycardia syndrome.

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).

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).