Distinguishing syncopal from non-syncopal causes of fall in older people

Abstract

Syncope is the mechanism by which cardiovascular abnor-malities may cause falls in older people. Syncope is a symp-tom, defined as a transient, self-limited loss ofconsciousness, usually leading to falling. The onset of syn-cope is relatively rapid, and the subsequent recovery isspontaneous, complete and usually prompt. The underlyingmechanism is a transient global cerebral hypoperfusion [1,2]. Syncopal loss of consciousness invariably determinesloss of postural tone and, if it occurs in the upright position,falling. Irrespective of the precise underlying cause of syn-cope, a sudden cessation of cerebral blood flow for 6–8 sand/or a decrease in systolic blood pressure to 60 mm Hghas been shown to be sufficient to cause complete loss ofconsciousness. Further, it has been estimated that as little asa 20% drop in cerebral oxygen delivery is sufficient to causeloss of consciousness.Syncope is common amongst older people. In theFramingham study [3], the 10-year cumulative incidence ofsyncope was 6%. The incidence was not, however, con-stant but increased more rapidly from the age of 70 yearsupwards. The 10-year cumulative incidence of syncopewas 11% for both men and women aged 70–79 and 17%and 19% for men and women, respectively, aged 80 orover. The incidence of syncope in an elderly institutional-ised population was 6% per year, with a 10-year prevalenceof 23% and a recurrence rate of 30% [4]. Age-associatedphysiological changes in heart rate, blood pressure, cere-bral blood flow, baroreflex sensitivity and intravascularvolume regulation, combined with comorbid conditionsand concurrent medications, may all contribute to thehigher incidence of syncope in the older population [5].In terms of the immediate injurious consequences ofsyncope, major morbidity such as fractures and motor vehi-cle accidents has been reported in 6% of patients and minorinjury such as laceration and bruises in 29%. Recurrent syn-cope is associated with fractures and soft-tissue injury in12% of patients [6].