David M. Sengstock MD, MS
Mark A. Supiano MD
ESSENTIALS OF DIAGNOSIS
The incidence of syncope increases dramatically with advancing age. The incidence of syncope per 1000 person-years increases from 6 in the sixth decade of life to 11 in the seventh decade. The incidence is 17 and 20 for men and women, respectively, in the eighth decade. Almost 50% of emergency room visits for syncope are made by persons 65 years of age or older.
The diagnostic workup should be guided by clinical information obtained from the history and physical examination. Helpful historical information, physical examination findings, and ECG findings are listed in Table 17-1.
The pathognomonic feature of syncope is a sudden loss of consciousness and postural tone resulting from a decrease in cerebral blood flow. The loss of consciousness is brief, and recovery is rapid and spontaneous. A patient who experiences both dizziness and an episode of fainting has sustained a syncopal event.
History should include other syncope events, the patient's general medical problems, details of activities engaged in just before the syncopal event, and any associated symptoms.
Patients with a history of falls or fall-related injury should be assessed for preceding syncope to rule out a cardiac cause. All patients should be questioned about chest pain, palpitations, and dyspnea on exertion. An assessment of cardiac risk should include a family history of sudden or unexplained death. The patient's medication list should be carefully reviewed.
Information from witnesses, if available, provides a valuable complement to clinical history supplied by the patient. Although rhythmic movements may be seen during a syncopal event, witnesses will generally describe the patient as motionless and flaccid. Postevent confusion is not commonly seen with syncope; prolonged confusion is more consistent with a seizure.
Noncardiac causes for syncope occur much less frequently in elderly individuals but can still lead to considerable morbidity from falls. To elicit noncardiac causes, the patient should be asked about any associated activity such as coughing, urination/defecation, or eating. If an emotionally stressful event occurred just before the syncope, a vasovagal cause for the syncope should be considered. Associated warm feeling, diaphoresis, or flushing as well as gastrointestinal symptoms such as nausea support this diagnosis.
Examining the history of a sudden loss of consciousness can help differentiate psychiatric from vasovagal causes. Fainting accompanying an emotionally stressful event is not true syncope because the physiological vagal reflex does not occur in this condition. In the history, an individual with a psychiatric cause for fainting reports frequent attacks. Despite frequent events, there is no physical injury from a fall. Although seizure-like activity may also occur, loss of bowel/bladder control, injury, and postevent confusion are absent.
Cardiac examination should include assessment of the patient's carotid pulse. Delayed upstroke or low volume is consistent with aortic stenosis. Palpation for a displaced point of maximal impulse and extra sounds on auscultation raise the index of suspicion for cardiomyopathy. Auscultation may provide evidence for valvular heart disease. All patients should also undergo a resting
electrocardiogram (ECG). Further evaluation will be guided by findings on examination and ECG.
Table 17-1. Helpful history, physical examination, & ECG findings.
Clinical suspicion and differential diagnosis should guide laboratory testing. Hematocrit, electrolytes, and renal function tests are useful if anemia or volume depletion is suspected. However, routine testing has been shown to be of little diagnostic value. Likewise, more advanced testing such as cardiac enzymes should be reserved for situations in which the patient history supports a cardiac cause of syncope.
Further investigation should be based on data provided by history, examination, and ECG findings. If clear evidence for a cause is found, further assessment of that cause should be undertaken. Clinical suspicion of cardiac disease should prompt further workup.
position at varying angles. Sudden hypotension and bradycardia are considered positive responses; these positive responses are believed to occur as a result of provocation of a vagal mechanism. Testing may be augmented by the addition of isoproterenol (after excluding cardiac disease) or nitroglycerin in patients who do not exhibit responses during initial tilting. Despite numerous attempts to standardize testing procedures, variations in the maximum angle used during tilt and choice of provocative agents (isoproterenol or nitroglycerin) remain. Furthermore, the reproducibility of positive findings in a geriatric population is variable, and false-positive rates have been reported to be as high as 65%. Thus, it may be difficult to interpret tilt-table testing results in geriatric populations.
Diagnostic considerations of syncope overlap with those of dizziness. Therefore, the initial step in the evaluation of syncope is distinguishing it from dizziness (Table 17-2). The differential diagnosis for syncope includes both benign and life-threatening conditions (Table 17-3). The majority of syncopal episodes in elderly patients is due to cardiovascular causes.
Transient ischemia and strokes increase in frequency with age, but these conditions generally do not lead to loss of consciousness unless there is an accompanying seizure. The frequency of movement-induced syncope also increases with age. For example, orthostasis affects 6-30% of ambulatory elderly patients, and its prevalence has been documented to increase with age. A syncopal episode may be the presenting sign of the condition.
Syncope can be associated with specific movements. Orthostatic hypotension should be considered when syncope occurs after moving from a recumbent to a standing position or after a prolonged stationary stand. The most commonly accepted definition of orthostasis is a decrease of >20 mm Hg in systolic blood pressure or 10 mm Hg in diastolic blood pressure between supine and upright positions. Blood pressure should be measured in the recumbent position and then in the standing position at 1, 3, and 5 min because a fall in blood pressure may be delayed in the geriatric population.
Both carotid hypersensitivity and subclavian steal syndrome occur after head turning. Patients may report that symptoms are associated with neck pressure, including tight collars and neckties. Carotid massage may be used to detect induced atrioventricular block or other arrhythmias. However, a history of a recent stroke, myocardial infarction, and bruits on carotid examination are contraindications to this procedure. When testing for carotid hypersensitivity, continuous cardiac monitoring is a prudent precaution.
Seizure should not be overlooked as a cause for syncope because new onset of seizures is not uncommon after age 60. History of seizure and compliance with prescribed antiseizure medication should be discussed. History of an aura before the event, loss of consciousness,
associated loss of bowel or bladder continence, and postictal confusion should be sought. Injury caused by an associated fall is also supportive. Apart from seizure, primary neurological causes for syncope are unusual. Transient ischemic attacks and stroke may produce loss of consciousness by causing a seizure and are generally accompanied by other neurological symptoms and focal findings.
Table 17-2. Differentiating syncope & dizziness
Table 17-3. Differential diagnosis of syncope.
Treatment for patients with syncope should focus on the suspected underlying cause. Individuals with a cardiac cause are at risk for sudden death. Cardiac ischemia should be treated appropriately. Treatment options for arrhythmias may include pharmacological therapies or pacemaker insertion. Patients with compromised ventricular function have been shown to benefit from automatic implantable cardioverter defibrillators.
Movement-induced causes for syncope are often difficult to treat. Patients and caregivers should be educated about fall risk and lifestyle changes directed at minimizing risks. Individuals with carotid sinus hypersensitivity should avoid exacerbating factors, including tight collars or rapid neck movement. When postprandial hypotension is a problem, patients should avoid large meals as well as physical activity after eating. Patients with orthostatic hypotension should be trained to rise from supine and seated positions slowly to allow time for compensatory mechanisms and to avoid prolonged standing. Orthostatic hypotension can be exacerbated both by poor oral intake and by medications. One study found antihypertensives and antidepressants to be commonly associated with postural hypotension; antianginal agents, analgesics, and central nervous system depressants were also implicated. The need for these medications should, therefore, be reviewed and, if possible, the medication discontinued. Recommendations to increase fluid and salt intake can be considered, but caution is advised because hypertension may be exacerbated. Compression stockings and isometric leg exercises may be helpful. In those with particularly symptomatic episodes, fludrocortisone acetate, a synthetic mineralocorticoid, may be considered. However, efficacy data in the treatment of orthostasis are lacking.
Vasovagal events are best treated by avoidance of the trigger, if possible. If symptoms occur during toileting, safety devices such as a bathtub safety bar and a toilet seat with armrests can be recommended. Patients referred for tilt-table testing have been shown to benefit from a simple procedure of leg crossing and muscle tensing for 30 s at the onset of symptoms. Paroxetine has been shown to improve symptoms in vasovagal syncope; however, this has not been verified in a geriatric population. Pacemaker implantation as a therapy for vasovagal syncope has received considerable support. However, confirmatory studies are not yet available. Therefore, caution is advised when referring patients for pacemaker implantation.
Individuals with syncope that remains unexplained by all investigations may have a psychiatric condition. Elderly individuals with dizziness or syncope of any
cause are at risk for traumatic injury. Falls represent a source of significant morbidity and mortality for elderly patients. The risk of automobile accidents is well recognized. Hazardous activity, such as driving, should be avoided during the evaluation period. Beyond this period, the length of time patients should refrain from driving is unclear; however, the American Heart Association recommends restricting a patient's driving privileges for several months.
Prognosis can be assessed by classifying patients as having cardiac, noncardiac, or unknown causes for syncope. Patients with cardiac problems have a much worse prognosis than those with a noncardiac or an unexplained cause.
Because the cause of syncope is not always determined and treatment options are limited, symptoms tend to recur: 15% of patients have a recurrence of syncope in an 18-mo follow-up. Patients with vasovagal syncope and those with unexplained syncope have approximately the same recurrence rates: 17% and 15%, respectively. Only 9% of the cardiac syncope patients have a recurrent episode; therapies aimed at the cardiac cause may influence recurrence rates.
EVIDENCE-BASED POINTS FOR SYNCOPE
ESSENTIALS OF DIAGNOSIS
Dizziness is a common symptom that increases in prevalence with age. In the majority of patients, symptoms recur for at least 1 year. Despite the frequency and disabling nature of dizziness, <50% of those seeking medical attention report relief.
The diagnostic workup should be guided by clinical information obtained from the history and physical examination. Helpful historical information, physical examination findings, and other specialized tests are listed in Table 17-4.
Dizziness is generally defined by 4 categories of symptoms: (1) vertigo, or perception of movement; (2) dysequilibrium, or loss of balance without an abnormal sensation of movement; (3) presyncope, or feeling of impending loss of consciousness, (4) light-headedness, or vague symptoms that do not fall into any of the former 3 categories. It is important to note that these categories are nonspecific, and a disorder can present with any or all of these symptoms.
Peripheral causes of vertigo are commonly accompanied by nausea, nystagmus, and postural instability. The most common peripheral causes of vertigo are
labyrinthitis, Ménière's disease, and benign positional vertigo. Acute labyrinthitis, also termed vestibular neuronitis or viral neuritis, is the most common of these. Vertigo caused by labyrinthitis develops over a period of days and generally resolves within about 1 week. However, a sense of unsteadiness may last considerably longer (weeks to months). Ménière's disease is typically characterized by low- and high- frequency hearing loss and tinnitus. Episodes of vertigo tend to recur and the hearing loss fluctuates.
Table 17-4. History, physical examination, & further testing.
Benign positional vertigo (BPV) is suggested by complaints of dizziness with a change in head position. The Dix-Hallpike maneuver is commonly used to screen for BPV and can be positive in as many as 44% of patients. This maneuver is performed by having the patient sit on the examination table with the head turned to one side. The patient is instructed to keep the eyes open throughout the test, even when dizziness is experienced. With the assistance of the examiner, the patient quickly lies down so that the ear faces downward. The examiner then checks for nystagmus. The test is repeated with the patient's head turned in the opposite direction. Hyperextension of the neck is often suggested but may not be possible because of arthritis or kyphosis. A positive test is indicated by horizontal or rotational nystagmus and symptoms of vertigo.
Risk factors for dizziness (eg, cardiovascular or cerebrovascular disease, impaired hearing, orthostasis, anxiety or depression, multiple medications) should be sought. Inquiring about movements that elicit dizziness may reveal that symptoms are produced by moving from a recumbent to an upright position, rotating the neck, or walking. Associated symptoms of tinnitus, hearing changes, and nausea may help in the differential diagnosis. Symptoms of ear discomfort, sinus pain, hearing loss, and general malaise should be sought. The
patient's medications should be carefully reviewed because they may be the cause of the dizziness.
Routine laboratory testing is not recommended because it is generally of little value. However, complete blood count, serum electrolytes, blood urea nitrogen, and creatinine may be useful if anemia or volume depletion is under consideration. If metabolic causes of dizziness are suspected, appropriate blood tests should be ordered. Because dizziness can accompany any systemic viral or bacterial infection, laboratory evaluation for the suspected infection should be completed.
Dizziness is a nonspecific symptom, and most causes are benign and self-limited. Because dizziness is not usually an urgent problem, time is available to complete a structured evaluation. However, several diagnoses should be considered immediately when the patient first presents with dizziness (Table 17-5). Patients with presyncope who are at high risk for cardiac events should be evaluated urgently in the same manner as those with syncope. An intracranial or neurological cause such as meningitis or intracranial hemorrhage should be considered in those with dizziness and headache, especially when there is a history of infectious exposure or trauma. Anemia or volume depletion may present with dizziness, and a history of melena should be sought. Finally, carbon monoxide poisoning often presents with vague symptoms, including dizziness, and, therefore, should not be overlooked.
All conditions in which treatment options are clear must be addressed. Depression, polypharmacy, and dehydration should be evaluated and treated appropriately. Efforts should also be directed at maximizing compensatory mechanisms. Vision should be evaluated, and patients should be encouraged to increase nighttime lighting. A cane or walker may be suggested for
extra stability, especially for those at risk for falls. Physical therapy may be helpful when gait instability is a problem. Patients should use caution with driving or when falling is a risk. Although driving guidelines for dizzy patients are less stringent than for syncope patients, avoidance of driving is reasonable if symptoms occur continuously or unpredictably.
Table 17-5. Differential diagnosis of dizziness.
The Epley procedure has become standard therapy for benign paroxysmal positional vertigo. The procedure attempts to induce dizziness, which, presumably, promotes compensation by the central nervous system. The patient is asked to sit on a bed with the head turned at a 45° angle. A pillow is placed so that, when the patient lies backward, it will be under the shoulders. The patient then lies backward quickly and waits for 30 s. The head is then turned to the opposite side, and the patient waits another 30 s. Finally, the patient rolls the body in the direction that he or she is facing and waits 30 s more. This should be carried out 3 (or more) times daily until vertigo is resolved.
In patients with chronic dizziness, referral for vestibular rehabilitation should be considered. Patients are asked to perform a number of eye, head, and body movements designed to reproduce dizziness. Although data supporting effectiveness are limited, a trial is reasonable because the procedure is noninvasive.
Attempts should be made to maximize functionality. Persistent dizziness can be distressing, and patients often report impairment in lifestyle because of concerns about physical harm resulting from falling, social embarrassment, and fears that symptoms signify a potentially serious illness. Alleviation of these fears should be considered an important goal. Reassurance and instruction in exercises have been shown to relieve concerns and improve functionality.
Meclizine, benzodiazepines, and diphenhydramine have been recommended for the treatment of dizziness. However, the risk of sedation and falls argues against their use in older patients. Meclizine may be helpful in acute episodes of vertigo. However, its safety and effectiveness have not been proven. Therefore, its use in chronic or nonvertiginous dizziness is not recommended.
Dizziness usually resolves spontaneously over weeks to months. Patients should be reassured that serious disorders (brain tumor, stroke, cardiac arrhythmia) are rare.
EVIDENCE-BASED POINTS FOR DIZZINESS
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