Orthostatic hypotension | |
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Other names | Orthostasis (elliptical jargon), postural hypotension, positional hypotension, neurogenic orthostatic hypotension |
Specialty | Cardiology, neurology |
Symptoms | Symptoms that are worse when sitting or standing and improve when lying down, including lightheadedness, vertigo, tinnitus, slurred speech, confusion, coathanger pain in neck and shoulders, grayed or blurred vision, severe fatigue, fainting or near fainting |
Complications | Cumulative brain damage, sudden death from falls |
Diagnostic method | In-office (lie down for at least 20 minutes, take BP; stand for 3 minutes, take BP), or tilt-table testing by an autonomic specialist |
Treatment | Identify and treat causes (medications, dehydration), midodrine, compression garments, bed tilting |
Prognosis | Depends on frequency, severity, and underlying cause; neurogenic orthostatic hypotension is a chronic, debilitating, and often progressively fatal condition[1] |
Orthostatic hypotension, also known as postural hypotension,[2] is a medical condition wherein a person's blood pressure drops when they are standing up (orthostasis) or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension.[3] The drop in blood pressure may be sudden (vasovagal orthostatic hypotension), within 3 minutes (classic orthostatic hypotension) or gradual (delayed orthostatic hypotension).[4] It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg after 3 minutes of standing. It occurs predominantly by delayed (or absent) constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.
Very mild occasional orthostatic hypotension is common and can occur briefly in anyone, although it is prevalent in particular among the elderly and those with known low blood pressure. Severe drops in blood pressure can lead to fainting, with a possibility of injury. Moderate drops in blood pressure can cause confusion/inattention, delirium, and episodes of ataxia. Chronic orthostatic hypotension is associated with cerebral hypoperfusion that may accelerate the pathophysiology of dementia.[5] Whether it is a causative factor in dementia is unclear.[6]
The numerous possible causes for orthostatic hypotension include certain medications (e.g. alpha blockers), autonomic neuropathy, decreased blood volume, multiple system atrophy, and age-related blood-vessel stiffness.
Apart from addressing the underlying cause, orthostatic hypotension may be treated with a recommendation to increase salt and water intake (to increase the blood volume), wearing compression stockings, and sometimes medication (fludrocortisone, midodrine, or others). Salt loading (dramatic increases in salt intake) must be supervised by a doctor, as this can cause severe neurological problems if done too aggressively.