Orthostatic hypotension

Orthostatic hypotension, also known as postural hypotension,

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.

Signs and symptoms

Orthostatic hypotension is characterized by symptoms that occur after standing (from lying or sitting), particularly when done rapidly. Many report

The disorder may be associated with Addison's disease, atherosclerosis (build-up of fatty deposits in the arteries), diabetes, pheochromocytoma, porphyria,^[15] and certain neurological disorders, including autoimmune autonomic ganglionopathy, multiple system atrophy, and other forms of dysautonomia. It is also associated with Ehlers–Danlos syndrome and anorexia nervosa. It is also present in many patients with Parkinson's disease or Lewy body dementias resulting from sympathetic denervation of the heart or as a side effect of dopaminomimetic therapy. This rarely leads to fainting unless the person has developed true autonomic failure or has an unrelated heart problem.^{[citation needed]}

Another disease, dopamine beta hydroxylase deficiency, also thought to be underdiagnosed, causes loss of sympathetic noradrenergic function and is characterized by low or extremely low levels of norepinephrine, but an excess of dopamine.^[16]

Quadriplegics and paraplegics also might experience these symptoms due to multiple systems' inability to maintain normal blood pressure and blood flow to the upper part of the body.^{[citation needed]}

Causes

Some causes of orthostatic hypotension include

Orthostatic hypotension can be a side effect of certain

Orthostatic hypotension can be confirmed by measuring a person's blood pressure after lying flat for 5 minutes, then 1 minute after standing, and 3 minutes after standing.[26] Orthostatic hypotension is defined as a fall in systolic blood pressure of at least 20 mmHg or the diastolic blood pressure of at least 10 mmHg between the supine reading and the upright reading. Also, the heart rate should be measured for both positions. A significant increase in heart rate from supine to standing may indicate a compensatory effort by the heart to maintain cardiac output. A related syndrome, postural orthostatic tachycardia syndrome (POTS), is diagnosed when at least a 30 bpm increase in heart rate occurs with little or no change in blood pressure. A tilt table test may also be performed.^[27]

Definition

Orthostatic hypotension (or postural hypotension) is a drop in blood pressure upon standing. One definition (AAFP) calls for a systolic blood pressure decrease of at least 20 mm Hg or a diastolic blood pressure decrease of at least 10 mm Hg within 3 minutes of standing.^[28] A common first symptom is lightheadedness upon standing, possibly followed by more severe symptoms: narrowing or loss of vision, dizziness, weakness, and even syncope (fainting).^{[citation needed]}

Subcategories

Orthostatic hypotension can be subcategorized into three groups – initial, classic, and delayed.^[29][30][31]

Initial orthostatic hypotension is frequently characterized by a systolic blood pressure decrease of ≥40 mmHg or diastolic blood pressure decrease of ≥20 mmHg within 15 seconds of standing.^[29] Blood pressure then spontaneously and rapidly returns to normal, so the period of hypotension and symptoms is short (<30 s).^[29] Only continuous beat-to-beat BP measurement during an active standing-up maneuver can document this condition.^[29]

Classic orthostatic hypotension is frequently characterized by a systolic blood pressure decrease of ≥20 mmHg or diastolic blood pressure decrease of ≥10 mmHg between 30 seconds and 3 min of standing.^[30]

Delayed orthostatic hypotension is frequently characterized by a sustained systolic blood pressure decrease of ≥20 mm Hg or a sustained diastolic blood pressure decrease ≥of 10 mm Hg beyond 3 minutes of standing or upright tilt table testing.^[31]

Management

Lifestyle changes

Apart from treating underlying reversible causes (e.g., stopping or reducing certain medications, treating autoimmune causes), several measures can improve the symptoms of orthostatic hypotension and prevent episodes of syncope (fainting). Even small increases in the blood pressure may be sufficient to maintain blood flow to the brain on standing.^[30]

In dysautonomic patients who do not have a diagnosis of high blood pressure, drinking 2–3 liters of fluid a day and taking 10 g of salt can improve symptoms, by maximizing the amount of fluid in the bloodstream.^[30] Another strategy is keeping the head of the bed slightly elevated. This reduces the return of fluid from the limbs to the kidneys at night, thereby reducing nighttime urine production and maintaining fluid in the circulation.^[30] Various measures can be used to improve the return of blood to the heart; the wearing of compression stockings and exercises ("physical counterpressure maneuvers" or PCMs) can be undertaken just before standing up (e.g., leg crossing and squatting).^[30]

Medications

The medication midodrine can benefit people with orthostatic hypotension,^[30][32] The main side effect is piloerection ("goose bumps").^[32] Fludrocortisone is also used, although based on more limited evidence.^[30]

Droxidopa has been shown to be effective as well,^[33] with few, mostly mild side effects reported.^[34]

A number of other measures have slight evidence to support their use –

Robotic devices, such as the Erigo medical device, have been proven to help orthostatic hypotension in some patients. These machines adjust a patient's position from 0 degrees to 90 degrees in progressive increments, allowing the blood pressure to adjust more slowly.[36]

Prognosis

Orthostatic hypotension may cause

• Orthostatic hypertension
• Orthostatic intolerance
• Vasovagal response

References