What is orthostatic hypotension?

From the Guidelines

Orthostatic hypotension is a condition where blood pressure drops significantly when a person stands up from sitting or lying down, causing symptoms like dizziness, lightheadedness, blurred vision, weakness, or fainting, and is defined as a decrease in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg within three minutes of standing, as stated in the 2005 American Heart Association guidelines 1.

Definition and Diagnosis

This condition occurs because normally when we stand, blood pools in our legs due to gravity, and our body compensates by constricting blood vessels and increasing heart rate. In orthostatic hypotension, this compensatory mechanism fails. The diagnosis of orthostatic hypotension can be made using a beat-to-beat blood pressure measurement on active standing test or a tilt-table test, as described in the 2018 European Heart Journal guidelines 1.

Causes and Risk Factors

Common causes of orthostatic hypotension include dehydration, certain medications (especially blood pressure medications, antidepressants, and diuretics), neurological disorders like Parkinson's disease, diabetes, heart problems, prolonged bed rest, aging, and alcohol consumption. Additionally, orthostatic hypotension can be associated with supine hypertension, which can lead to life-threatening target organ damage, as noted in the 2005 American Heart Association guidelines 1.

Treatment and Management

Treatment of orthostatic hypotension typically involves addressing underlying causes, increasing fluid and salt intake, wearing compression stockings, rising slowly from sitting or lying positions, and avoiding triggers like hot environments or large meals. Medications may be necessary in severe cases, including midodrine (2.5-10 mg three times daily) and droxidopa (100-600 mg three times daily), which are approved by the FDA for the treatment of orthostatic hypotension, as stated in the 2022 Diabetes Care guidelines 1.

Key Considerations

It is essential to note that classical orthostatic hypotension is associated with increased mortality and cardiovascular disease prevalence, as described in the 2018 European Heart Journal guidelines 1. Therefore, the therapeutic goal is to minimize postural symptoms rather than to restore normotension, and treatment should be individualized based on the underlying cause and severity of symptoms.

From the Research

Definition and Diagnosis of Orthostatic Hypotension

• Orthostatic hypotension is defined as a decrease in blood pressure of 20 mm Hg or more systolic or 10 mm Hg or more diastolic within three minutes of standing from the supine position or on assuming a head-up position of at least 60 degrees during tilt table testing 2.
• Diagnosis is confirmed by performing a bedside simplified Schellong test, which consists of blood pressure and heart rate measurements after five minutes in the supine position and three minutes after moving to a standing position 2.
• If the patient is unable to stand safely or the clinical suspicion for orthostatic hypotension is high despite normal findings on the bedside test, head-up tilt table testing is recommended 2.

Symptoms and Prevalence of Orthostatic Hypotension

• Symptoms of orthostatic hypotension include headache, lightheadedness, shoulder and neck pain (coat hanger syndrome), visual disturbances, dyspnea, and chest pain 2.
• The prevalence of orthostatic hypotension in the community setting is 20% in older adults and 5% in middle-aged adults 2.
• Risk factors such as diabetes mellitus increase the prevalence of orthostatic hypotension in all age groups 2.

Classification and Treatment of Orthostatic Hypotension

• Orthostatic hypotension is classified as neurogenic or nonneurogenic, depending on etiology and heart rate response 2.
• Treatment goals for orthostatic hypotension are reducing symptoms and improving quality of life 2.
• Initial treatment focuses on the underlying cause and adjusting potentially causative medications 2.
• Nonpharmacologic strategies include dietary modifications, compression garments, physical maneuvers, and avoiding environments that exacerbate symptoms 2.
• First-line medications include midodrine and droxidopa 2.

Complications and Prognosis of Orthostatic Hypotension

• Orthostatic hypotension is associated with a significant increase in cardiovascular risk and falls, and up to a 50% increase in relative risk of all-cause mortality 2.
• Orthostatic hypotension has been extensively studied and numerous prospective cohort studies support its association with adverse events, including coronary artery disease, heart failure, stroke, cognitive dysfunction, and mortality rates 3.
• Randomized data evaluating the impact of therapeutic interventions on morbidity and mortality outcomes are lacking 3.

Pathophysiology and Causes of Orthostatic Hypotension

• Orthostatic hypotension is considered a manifestation of dysfunction of the autonomic nervous system, caused or facilitated by several neurological or non-neurological diseases and conditions 3.
• Failure of peripheral vasoconstriction seems to play a more important role than the defect in reflex tachycardia 4.
• Causes of orthostatic hypotension are multiple and may occur in healthy subjects, when exposed to exceptional circumstances, but is more generally associated with various diseases, either neurological disorders or pathologies characterized by hypovolemia 4.
• Medications can also aggravate the risk of orthostatic hypotension, among which some antihypertensive or psychotropic agents 4.