17 Dizziness and Syncope Rainier P. Soriano Learning Objectives Upon completion of the chapter, the student will be able to: 1. Describe the mechanisms that give rise to symptoms of dizziness and syncope among older adults. 2. Create a differential diagnosis for etiologies of dizziness and syncope in older adults utilizing key historical and physical examination data to create a differential diagnosis. 3. Identify and describe the prognosis and treatment of the common causes of dizziness and syncope in the elderly. Case A (Part 1) Mrs. Adams is a 69-year-old retired executive secretary. She is currently a hospital volunteer escorting newly admitted patients to their rooms and helping with patient transport around the hospital. She comes to your offi ce with the following complaint: “Dr. Smith, I feel dizzy most of the time. What is causing this problem?” Dizziness: General Considerations Dizziness is a subjective sensation of postural instability or of illusory motion. It is one of the most common presenting complaints in primary care practice for persons aged 65 years and older. The prevalence of Material in this chapter is based on the following chapters in Cassel CK, Leipzig RM, Cohen HJ, Larson EB, Meier DE, eds. Geriatric Medicine: An Evidence- Based Approach, 4th ed. New York: Springer, 2003: Kapoor WN. Syncope in the Elderly, pp. 957–966. Nanda A, Tinetti ME. Chronic Dizziness and Vertigo, pp. 995–1008. Selections edited by Rainier P. Soriano. 304 17. Dizziness and Syncope 305 dizziness ranges from 4% to 30% in this age group. Dizziness is a word used by different people to describe many different phenomena. It is a nonspecifi c term that includes vertigo, dysequilibrium, lightheadedness, spinning, giddiness, faintness, fl oating, feeling woozy, and many other sensations. Age-Associated Changes Related to Dizziness Evidence suggests that age-related changes occur in each of the vestibular, visual, auditory, and proprioceptive systems. Although these age-related changes do not likely cause clinical disease, they may predispose older persons to the occurrence of dizziness by making them more vulnerable to the effects of superimposed impairments and diseases. Degenerative changes and reductions in the number of sensory cells (hair cells) in the semicircular canals, saccule, and utricle have been reported with aging. Age-related visual changes include a decrease in visual acuity, dark adapta- tion, contrast sensitivity, and accommodation. Age-related decline in pro- prioception has not been extensively studied. Diagnostic Evaluation Symptoms and Signs An evaluation of dizziness begins with the clinical history. The patient should be asked to be as precise as possible about the sensations of dizzi- ness, an often diffi cult task because patients may experience more than one manifestation or a vague sensation. The frequency and duration of dizziness, as well as any associated symptoms such as hearing loss, ear fullness, tinnitus, diplopia, dysarthria, and syncopal episodes, are all important. The physician should also ask about comorbid conditions, for example, cardiac diseases, diabetes, renal disorders, anxiety, or depression, which can predispose or exacerbate dizziness. A careful review of all medi- cations, including over-the-counter drugs, is also important. The physical examination should include measurements of orthostatic changes in blood pressure. One should look for cerebellar signs, for example, gait ataxia, truncal ataxia, or dysmetria, which suggest etiologies such as a cerebellar stroke or cerebellopontine angle tumors. A detailed history and physical examination should help the physician in identifying one or more causes responsible for dizziness. Although 50% of dizziness in older adults cannot be clearly assigned to one type, the most common specifi c symptoms that are vaguely labeled dizziness can be classifi ed as shown in Table 17.1. 306 Rainier P. Soriano Table 17.1 Symptomatic categories of persons complaining of dizziness (26) Vertigo: A defi nite rotational sensation or a sense of environmental motion. Vertigo is considered to result from a disturbance within the vestibular system or its connections. The patient may complain, “My head is spinning” or “The room is whirling.” (Pre) syncope: Actual loss of consciousness or the sensation that loss of consciousness is about to happen. Presyncope is usually considered to result from a hypoperfusion of the brain. Common complaints include “I might pass out” or “I feel faint.” Dysequilibrium: Sensation that balance (especially during ambulation) is impaired, but usually without the sensation of vertigo or near fainting. Dysequilibrium usually results from abnormalities in the proprioceptive system. Common complaints: “My balance is off” or “I might fall.” Lightheadedness: A vague term that refers to a head sensation that is nonvertiginous and nonsyncopal. The patient may describe, “fl oating,” “wooziness,” “spaciness,” “whirling,” and other nonspecifi c sensations. Commonly: “I’m just dizzy.” Source: Adapted from Reilly BM. Dizziness. In: Reilly BM, ed. Practical Strategies in Out- patient Medicine, 2nd ed. Philadelphia: WB Saunders, 1991; and Nanda A, Tinetti ME. Chronic Dizziness and Vertigo. In: Cassel CK, Leipzig RM, Cohen HJ, et al., eds. Geriatric Medicine, 4th ed. New York: Springer, 2003:995–1008. Provocative Tests Apart from the history and physical examination, certain provocative tests can be done at the bedside to evaluate the vestibular system. The most common causes of dizziness can be quickly diagnosed by reproducing a patient’s symptoms. However, some of these maneuvers should be per- formed (if at all) cautiously. To see if the vestibulo-ocular refl ex (VOR), which helps to maintain visual stability during head movement, is intact, the following three tests can be done. The sensitivities, specifi cities, and predictive values of these tests for vestibular lesions in older persons have not been established. Head-Thrust Test In the head-thrust test, the patient is asked to fi xate on the examiner’s nose, and the head is moved rapidly by the examiner about 10 degrees to the left or right. In a normally functioning VOR, the eyes will be fi xed on the target, whereas in patients with a vestibular defi cit, the eyes are carried away from the target along with the head, followed by a corrective saccade back to the target. For example, in a patient with a right-sided vestibular lesion, head thrusts to the right produce a slipping away of the pupils from the target followed by a corrective movement back to the target, whereas head thrusts to the left produce a normal response of the eyes. Post–Head-Shake Test In the post–head-shake test, the head is rotated either passively by the ex- aminer or actively by the subject at a frequency of about 2 Hz in the horizon- tal plane for about 10 seconds, and then the examiner looks for nystagmus when the head is stopped. In unilateral peripheral vestibular lesions, there will be a horizontal nystagmus with the fast phase usually beating toward the stronger ear, whereas in central lesions the nystagmus may be vertical. 17. Dizziness and Syncope 307 Dynamic Visual Acuity Testing This test is done by asking the patient to read a fi xed eye chart while the examiner moves the head horizontally at a frequency of 1 to 2 Hz. A drop in acuity of two rows or more from the baseline is suggestive of an abnor- mal VOR. This test is sometimes diffi cult to perform, because patients may be able to read at times when the head is not in motion (i.e., at turnaround points or by resisting movements). These tests are more helpful in detect- ing unilateral than bilateral vestibular dysfunction. It is important to remember that compensatory mechanisms may mask a vestibular defi cit when these maneuvers are used in patients with longstanding vestibular loss. If the fi ndings of these tests are abnormal, then the patient can be referred for more sophisticated vestibular testing such as electronystag- mography and rotational testing. Stepping Test This test is positive when there is a lesion in the vestibulospinal system. The patient is asked to stand at the center of a circle drawn on the fl oor. The circle is divided into sections by lines passing at 30-degree angles. The patient is blindfolded and is asked to outstretch both arms at 90 degrees to the body. The patient is then asked to fl ex and raise high fi rst one knee and then the other, and to continue stepping forward at a normal walking speed for a total of 50 or 100 steps. The examiner notes body sway while the patient marches in place with the eyes closed. In a unilateral vestibular lesion or in acoustic neuroma, there will be a gradual rotation of the body (more than 30 degrees) toward the affected side. Dix-Hallpike Maneuver (Nylan-Barany Test) This test can defi nitively establish a diagnosis of benign paroxysmal posi- tional vertigo (BPPV). In this maneuver, the patient is seated on an exami- nation table with the head rotated 30 to 45 degrees to one side. The patient is asked to fi x his/her vision upon the examiner’s forehead. The examiner holds the patient’s head fi rmly in the same position and moves the patient from a seated to a supine position with the head hanging below the edge of the table and the chin pointing slightly upward. The examiner should note the direction, latency, and duration of the nystagmus and the latency and duration of vertigo, if present. Laboratory Findings A small battery of laboratory tests should be performed on all patients with dizziness because the prevalence of undetected abnormalities is high and because results often lead to effective treatment. Hematocrit, glucose, blood urea nitrogen, electrolytes, thyroid function tests, and vitamin B12 308 Rainier P. Soriano levels should be ordered in all patients complaining of dizziness.