![]() ![]() During tilt table testing and measurement of orthostatic vital signs, OH is associated with an appropriate but ultimately ineffective tachycardic response as opposed to the cardioinhibition seen in VSS and CSS. A significant decline in blood pressure that occurs immediately after standing but resolves within 3 minutes is not usually of clinical concern however, failure to resolve has been linked to an increased risk of falling even in asymptomatic individuals. Identifying orthostatic hypotension at the bedside can be difficult as blood pressure responses are not always reproducible and repeat assessments are often needed. 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. Loss of consciousness occurs when the neuroautonomic response is impaired and cerebral blood flow is not maintained. ![]() Under normal conditions, a neuroautomomic tachycardic response follows orthosis in order to maintain adequate cardiac output and peripheral vasoconstriction. When an adult assumes the standing position, approximately 300 to 800 mL of blood pools in the lower limb vasculature. Neuroautonomic syncope is defined as “age-related changes in blood pressure and heart rate behavior, predominately resulting in hypotension and bradyarrhythmia.” Neuroautonomic syncope encompasses four distinct syndromes: orthostatic hypotension (OH), vasovagal syncope (VVS), carotid sinus syndrome (CSS), and postprandial hypotension. The local jurisdiction’s laws respecting syncope and the operation of motor vehicles or aircraft should also be considered. Regardless of the cause, all patients presenting with syncope should have their bone health assessed and be treated for osteoporosis if appropriate and prescribed hip protectors. Neuroautonomic syncope, cardiac syncope, and syndromes with syncope-like symptoms ( Table 1) are common causes of syncopal events. In the emergency department, risk stratification scales have been developed and internally validated, but consequent external validation has demonstrated poor specificity. This diagnostic uncertainty can lead to a multiplicity of expensive but very low-yield investigations. A prospective study of a complete clinical evaluation for syncope, which included tilt table testing, Holter monitoring, and implantable loop recorder (ILR) monitoring, was unable find a cause for the episode one-quarter of the time. Often, the cause of a syncopal spell can be impossible to determine. Syncope should thus be considered a possible contributing factor in any unexplained fall in an older adult. The fact that most falls in older adults are unwitnessed compounds the challenge presented by patients unable to recall presyncopal complaints. This lack of recall is even worse in cognitively impaired patients. 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. 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). 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. Because rates of syncope increase with age, older adults are especially vulnerable to syncope-related injury. Approximately 3% of all visits to the emergency department are due to syncope. ![]()
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