What causes orthostatic hypotension in the elderly?

From the Guidelines

Orthostatic hypotension in the elderly is primarily caused by a combination of factors, including age-related decline in autonomic function, hypertension, and the use of certain medications, such as antihypertensive drugs and diuretics.

Key Factors Contributing to Orthostatic Hypotension

• Age-related decline in autonomic function: As people age, their autonomic nervous system's ability to regulate blood pressure and heart rate in response to changes in posture is impaired, leading to orthostatic hypotension 1.
• Hypertension: Hypertension itself, as well as the medications used to treat it, can increase the risk of orthostatic hypotension 1.
• Medications: Certain medications, such as alpha-blockers, diuretics, and other vasoactive drugs, can exacerbate orthostatic hypotension by further reducing blood pressure or impairing the body's ability to compensate for changes in posture 1.
• Deconditioning and hypovolemia: Reduced physical fitness and decreased blood volume can also contribute to orthostatic hypotension, particularly in the elderly 1.

Pathophysiology

Orthostatic hypotension occurs when the body is unable to maintain blood pressure in response to changes in posture, leading to a drop in systolic blood pressure of at least 20 mmHg or 10 mmHg in diastolic blood pressure within 3 minutes of standing 1. This can be due to a variety of factors, including impaired autonomic function, decreased blood volume, and medication side effects.

Clinical Implications

Orthostatic hypotension can lead to symptoms such as dizziness, lightheadedness, fatigue, and syncope, which can increase the risk of falls and other injuries in the elderly 1. Therefore, it is essential to identify and manage orthostatic hypotension in this population to prevent these complications.

From the Research

Causes of Orthostatic Hypotension in the Elderly

• Orthostatic hypotension in elderly people is often attributed to diminished afferent baroreflex sensitivity 2
• The cause of orthostatic hypotension is usually multifactorial, including reduced circulating volume, reduced peripheral resistance, and limited heart rate increase 3
• Aging coupled with diseases such as diabetes and Parkinson's disease can result in baroreflex failure, leading to orthostatic hypotension 4
• Other causes of orthostatic hypotension include autonomic dysfunction, leading to neurogenic orthostatic hypotension 3
• Certain medications, such as diuretics, antidepressants, sympatholytics, and vasodilators, can also contribute to orthostatic hypotension 3

Mechanisms and Risk Factors

• Orthostatic hypotension occurs when mechanisms for the regulation of orthostatic blood pressure control fail, depending on the baroreflexes, normal blood volume, and defenses against excessive venous pooling 4
• The condition is common in the elderly and is associated with an increased mortality rate 4
• Orthostatic hypotension is also associated with cardiovascular risk factors, including cerebrovascular events, higher nocturnal blood pressure levels, and arterial stiffness 5
• Left ventricular mass index is significantly higher in subjects with orthostatic hypotension, suggesting a possible link between the condition and cardiovascular risk factors 5

Prevalence and Diagnosis

• Orthostatic hypotension commonly affects elderly patients, with a prevalence of 10-30% in this population 4
• The condition can be diagnosed through evaluation of blood pressure changes in response to postural changes, as well as assessment of autonomic function and other underlying medical conditions 6