Orthostatic Hypotension

Summary

Description

• Orthostatic hypotension is the sudden drop in blood pressure provoked by adopting a more upright position, e.g. standing up. Condition may be asymptomatic, or may induce dizziness, lightheadedness, diaphoresis, vision changes, head and neck pain, and syncope
• Most prevalent among the elderly. Causes include prescription medications and over-the-counter drugs, hypovolemia, vasodilation, prolonged bed rest, and disorders of the autonomic nervous system
• Treatment should seek to remove underlying causes. When this is not possible, as is the case with neurogenic disease, patients may require a combination of medication, nonpharmacologic aids, and lifestyle changes

Synonyms

Urgent action

Severe orthostatic hypotension from hypovolemia may require intravenous fluid resuscitation.

Background

Cardinal features

• Fall in systolic blood pressure of at least 20mmHg or diastolic blood pressure of at least 10mmHg within 3min of rising to a more upright position
• May cause cerebral hypoperfusion, resulting in dizziness, blurred vision, lightheadedness, headache, neckache, palpitations, weakness, fatigue, diaphoresis, cognitive impairment, nausea, and/or syncope

Causes

Common causes

• Medications: phenothiazines, monoamine oxidase inhibitors, tricyclic antidepressants, diuretics, levodopa, bromocriptine, beta-blockers, calcium-channel blockers, nitrates, sildenafil, and some cytotoxics
• Hypovolemia (including that caused by dehydration, overdiuresis, diarrhea, hemorrhage, burns, fever, and hot environment)
• Decreased baroreceptor sensitivity - most common in the elderly
• Common general neuropathies affecting the peripheral autonomic nervous system, including diabetes mellitus, alcohol abuse, and amyloidosis
• Prolonged bed rest
• Salt-free diet
• Anemia

Rare causes

• Disorders involving blood vessels, including severe varicose veins, vasospastic disorders, and atherosclerosis
• Primary adrenal insufficiency (Addison's disease)
• Generalized neurologic disorders that affect the autonomic nervous system, including Parkinson's disease, multiple strokes, brain stem lesions, multiple system atrophy (MSA), e.g. Shy-Drager syndrome, and multiple sclerosis
• Specific autonomic nervous system disorders, including Riley-Day syndrome (familial dysautonomia), and pure autonomic failure (PAF) - previously called Bradbury-Eggleston syndrome, and postural orthostatic tachycardia syndrome (POTS)
• Uncommon disorders affecting primarily autonomic nervous system, including Guillain-Barré syndrome, dopamine-beta hydroxylase deficiency, AIDS, porphyria, and paraneoplastic syndromes
• Damage to the spinal cord, including that associated with syringomyelia and tabes dorsalis

Serious causes

All symptomatic orthostatic hypotension must be taken seriously as patients may develop syncope. Medication- and volume-induced hypotension are easier to treat than autonomic nervous system disorders.

Contributory or predisposing factors

• Normal aging process: aging is associated with reduced cerebral blood flow, possible impairment of the baroreflex, and reduced renal salt and water conservation
• Hypertension: age-related elevation in systolic blood pressure may impair the baroreflex. Moreover, drugs used to treat hypertension may cause orthostatic hypotension as a side-effect

Epidemiology

Incidence and prevalence