Carotid sinus hypersensitivity in elderly nursing home patients

Carotid sinus hypersensitivity is common in patients presenting with hip fracture and unexplained falls

BACKGROUND

We tried to determine the prevalence of carotid sinus hypersensitivity (CSH) in patients with hip fractures with and without a clear history of an accidental fall.

METHODS

We studied 51 patients hospitalized for a hip fracture and 51 matched controls from our outpatients department. All patients were subjected to a carotid sinus massage in the supine and upright position. Patients were categorized in accidental (Group A) and unexplained (Group B) fallers.

RESULTS

Six of 33 (18.2%) patients in Group A and 12 of 18 (66.7%) patients in Group B (P < 0.001) had a positive response to the carotid sinus massage. Nine controls (17.6%) also demonstrated CSH. Patients in Group B were older (A: 75.5 +/- 8.5 years vs B: 80.1 +/- 5.9 years, P =0.029) and were more likely to have a history of unexplained falls or syncope in the past (A: 0% vs B: 66.7%, P < 0.0001) than individuals in group A. Vasodepressor/mixed forms accounted for the majority of CSH responses in Group B (75%). When compared with the control group, CSH was still more common in Group B (B: 66.7% vs control: 17.6%, P < 0.0001) but not in Group A (A: 18.2% vs control: 17.6%, P =1.000).

CONCLUSIONS

The prevalence of CSH is increased in elderly patients with hip fractures, only in those who present with an unexplained fall and report a history of syncope or unexplained falls in the past. The vasodepressor/mixed forms account for the majority of CSH responses in the group of unexplained fallers.

Neurally mediated syncope and unexplained or nonaccidental falls in the elderly

Falls and syncope are among the leading causes for which older patients seek hospital admissions. The prevalence of unexplained or nonaccidental falls is high in this group. The clinical spectrum of falls and syncope has been shown to overlap significantly in the elderly. Carotid sinus syndrome and vasovagal syncope, the two common examples of neurally mediated syncope (NMS), have been increasingly recognised as important attributable causes for unexplained falls and syncope. However, in clinical practice NMS is not widely investigated as a cause of fall and is likely to be underdiagnosed.

Drop attacks in older adults: systematic assessment has a high diagnostic yield

OBJECTIVES

To investigate the causes of recurrent drop attacks in older patients with a comprehensive battery of investigations in the largest series reported to date.

DESIGN

Observational with mean followup of 18 months.

SETTING

Inner city emergency department and tertiary facility in Newcastle upon Tyne, United Kingdom.

PARTICIPANTS

Ninety-three consecutive patients aged 55 and older with three or more drop attacks in the 6 months before evaluation.

METHODS

Subjects underwent a comprehensive diagnostic evaluation, with particular attention to traditional (e.g., gait and balance abnormalities, medications) and more recently identified (e.g., carotid sinus hypersensitivity) risk factors for drop attacks.

RESULTS

Subjects tended to be older (mean age+/-standard deviation 77.4+/-9.0) and female (70; 75%) and to have a mean of 10.4 drop attacks before evaluation. Fifty-three (57%) had suffered soft tissue injuries needing medical attention and 32 (34%) fractures secondary to drop attacks. An attributable diagnosis was achieved in all but nine subjects (90%). Cardiovascular diagnoses (49; 53%) were most commonly implicated, with neurological (27; 29%) and gait and balance abnormalities (17; 18%) and drug-related causes (11; 12%) providing the majority of the remaining diagnoses.

CONCLUSION

Drop attacks in older subjects are associated with high levels of morbidity and healthcare resource utilization. Attributable diagnoses are achievable in the majority of cases with a systematic investigative approach. The high diagnostic yield more than justifies the approach described.

Carotid sinus syndrome

This article reviews the recent literature about carotid sinus syndrome. It looks principally at the various ways in which it may present, the limited knowledge of its pathophysiology, and the role of carotid sinus massage in the investigation of carotid sinus syndrome.

Neurocardiovascular instability in cognitive impairment and dementia

Neurocardiovascular instability (NCVI, neurally mediated disorders causing hypotension with or without bradycardia) represents abnormal neural control of the cardiovascular system and presents as dizziness, syncope, or falls. The mechanisms underpinning NCVI are incompletely understood. The three most common disorders are carotid sinus syndrome (CSS), orthostatic hypotension (OH), and vasovagal syndrome (VVS): CSS, cardioinhibition > 3 s and/or vasodepressor response > or = 50 mmHg drop in systolic pressure during carotid sinus stimulation; OH: fall in systolic blood pressure > 20 mmHg during standing; VVS: cardioinhibition > 3 s and/or vasodepressor response > 50 mmHg during prolonged head-up tilting. In fallers with cognitive impairment or dementia, the prevalence of NCVI is 70%. Multifactorial interventions, including treatment of NCVI, significantly reduce falls and syncope. The predominant components of NCVI in fallers with cognitive impairment and dementia are CSS and OH. In Lewy body and Alzheimer's dementia, the prevalence of NCVI is up to 60%, again predominantly CSS and OH. The prevalence of cardioinhibitory carotid sinus hypersensitivity is particularly high in Lewy body dementia-41% compared with 12% in Alzheimer's disease and 3% in case controls. In addition, patients with Lewy body dementia have greater heart rate slowing (>2 s) and falls in systolic blood pressure (>20 mmHg) than those with Alzheimer's disease or controls during carotid sinus stimulation. The extent of deep white matter hyperintensities on MRI correlates with systolic fall during carotid sinus stimulation (R = 0.58; p < 0.005), suggesting a possible causal association between bradyarrhythmia-induced hypotension and microvascular pathology. NCVI is common in patients with dementia and may be a reversible cause of falls and syncope. Repeated hypotensive episodes may exaggerate cognitive decline in these patients.

Neurally mediated syncope

The prevalence and incidence of syncope increases with advancing years due to age related physiological changes in the neurocardiovascular, endocrine and renal systems. Cardiovascular syncope can present as falls because of amnesia for loss of consciousness or postural instability due to hypotension. Drop attacks or non accidental falls should thus be investigated for causes of syncope. The most common causes of neurally mediated syncope in older adults are carotid sinus syndrome, orthostatic hypotension and vasovagal syncope.

The sympathetic nervous system and baroreflexes in hypertension and hypotension

Blood pressure and blood volume are closely regulated by the interrelated actions of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS). Reflex vasoconstriction caused by parallel SNS and RAAS activation is modulated by two interactive negative feedback systems called baroreflex. The aortic-carotid baroreflex systems respond to momentary changes in systolic blood pressure, adjusting the degree of SNS-dependent peripheral vasoconstriction and cardiac output to allow maintenance of a relatively constant perfusion pressure. Cardiopulmonary baroreflexes respond to momentary changes in cardiac filling, adjusting the degree of peripheral venoconstriction and venous return to maintain cardiac preload and stroke volume. Under normal conditions, each baroreflex system exhibits a degree of tonic negative feedback so that it can alter SNS output immediately, providing counterregulatory increases or decreases in pressure or volume to maintain homeostasis. The SNS is inappropriately active in obesity and hypertension and plays a causal or permissive role in all forms of chronic hypertension. If the negative feedback control exerted by the baroreflexes over the SNS and renin-angiotensin-aldosterone system (RAAS) were perfect, chronic hypertension would not occur. Activity of the baroreflexes, however, is chronically altered by maladaptive changes such as cardiac and vascular fibrosis and hypertrophy. Long-term increases in SNS and RAAS activity also exert ongoing deleterious effects on the heart and vasculature by directly facilitating further cardiac hypertrophy and arterial stiffening. These effects appear to contribute to a vicious cycle of chronic hypertension and target organ damage. Other syndromes of abnormal blood pressure (BP) control, including orthostatic hypotension and baroreflex failure are examples of abnormal baroreflex activity and SNS control.

Neurosurgical management of carotid sinus hypersensitivity. Report of three cases

Carotid sinus hypersensitivity (CSH) can cause severe bradycardia, hypotension, asystole, and cardiac arrest. Three patients with the combined (mixed) cardioinhibitory and vasodepressor form of CSH were studied with intensive cardiovascular monitoring. After medical management failed, the patients were successfully treated by transection of the glossopharyngeal nerve and upper rootlets of the vagus nerve at their exit from the brain stem. Methods of diagnosis of CSH, and the benefits and limitations of medical and surgical therapies are discussed.