Syncope in older adults

Falls in older adults are often the result of syncope, commonly defined as “a transient loss of consciousness.” Identifying the cause of syncope can be quite difficult, especially since syncoperelated falls in older adults are often not witnessed. A systemic approach can help distinguish between neuroautonomic and cardiac syncope, identify syndromes with syncopelike symptoms, and prevent fallrelated injuries, loss of independence, and mortality. Treatment varies, depending on the diagnosis, and can include pharmacological therapy, nonpharmacological therapy, and pacemaker insertion. Neuroautonomic syncope encompasses four distinct syndromes: orthostatic hypotension, vasovagal syncope, carotid sinus syndrome, and postprandial hypotension. Current guidelines define orthostatic hypotension as a drop in systolic blood pressure of 20 mm Hg or a drop in diastolic blood pressure of 10 mm Hg after standing upright for 3 minutes. The mechanisms behind vasovagal syncope remain poorly understood, although we do know that susceptibility is increased by dehydration, either through the administration of medications such as diuretics or through poor oral intake. Carotid sinus syndrome is characterized by an arterial baroreflex that is overly sensitive to oscillations in blood pressure levels, resulting in transient asystole and vasodilatation. Postprandial hypotension is an uncommon condition caused by increases in splanchnic blood flow after eating and can be addressed with diet modifications. Overall, cardiac syncope is less common than neuroautonomic syncope, but has a significant associated mortality, mainly due to injury. The main causes of cardiac syncope are organic heart disease and arrhythmias. Syndromes with syncope-like symptoms include hypoglycemia, seizures, transient ischemic attacks, and psychiatric conditions. Assessing syncope as a mechanism for falls can be quite challenging in the general population, and even more difficult in older adults with cognitive issues. A structured approach that includes obtaining information from collateral historians (family and care providers) can aid diagnosis and reduce the probability of future falls. A pproximately 3% of all visits to the emergency department are due to syncope. Because rates of syncope increase with age, older adults are especially vulnerable to syncope-related injury. Falls due to fainting, which often lead to hip fractures, hospital admissions, and institutionalization, have a direct cost to the Canadian health care system of $60 million a year. Syncope is commonly defined as “a transient loss of consciousness.” Both medical school and residency training teach that syncope is diagnosed primarily by symptoms preceding the loss of consciousness (e.g., giddiness, lightheadedness, tunnel vision, nausea, spots in the vision). Unfortunately, approximately 30% of cognitively normal older patients who experience syncope under controlled laboratory conditions (i.e., during tilt table testing) will not recall the event. This lack of recall is even worse in cognitively impaired patients. The This article has been peer reviewed. Dr Madden is an associate professor in the Gerontology and Diabetes Research Laboratory of the Division of Geriatric Medicine at the University of British Columbia. He is also a clinical scientist at the Centre for Hip Health and Mobility at UBC.