Initial Evaluation of VertigoBenign paroxysmal positional vertigo, acute vestibular neuronitis, and Ménière's disease cause most cases of vertigo; however, family physicians must consider other causes including cerebrovascular disease, migraine, psychological disease, perilymphatic fistulas, multiple sclerosis, and intracranial neoplasms. Once it is determined that a patient has vertigo, the next task is to determine whether the patient has a peripheral or central cause of vertigo. Knowing the typical clinical presentations of the various causes of vertigo aids in making this distinction. The history (i.e., timing and duration of symptoms, provoking factors, associated signs and symptoms) and physical examination (especially of the head and neck and neurologic systems, as well as special tests such as the Dix-Hallpike maneuver) provide important clues to the diagnosis. Associated neurologic signs and symptoms, such as nystagmus that does not lessen when the patient focuses, point to central (and often more serious) causes of vertigo, which require further work-up with selected laboratory and radiologic studies such as magnetic resonance imaging. (Am Fam Physician 2006;73:244-51, 25 Copyright © 2006 American Academy of Family Physicians.)

One of the most common and frustrating complaints patients bring to their family

physicians is dizziness. There are four types of dizziness: vertigo, lightheadedness, presyncope, and dysequilibrium. 1 The most prevalent type is vertigo (i.e., false sense of motion), which accounts for 54 percent of reports of dizziness in primary care.2 The differential diagnosis of vertigo (Table 11-6) includes peripheral vestibular causes (i.e.,

those originating in the peripheral nervous system), central vestibular causes (i.e., those originating in the central nervous system), and other conditions. Ninety-three percent of primary care patients with vertigo have benign paroxysmal positional vertigo (BPPV), acute vestibular neuronitis, or Ménière's disease.7 Other causes include drugs (e.g., alcohol, aminoglycosides, anticonvulsants [phenytoin (Dilantin)], antidepressants, antihypertensives, barbiturates, cocaine, diuretics [furosemide (Lasix)], nitroglycerin, quinine, salicylates, sedatives/hypnotics),8,9 cerebrovascular disease, migraine, acute labyrinthitis, multiple sclerosis, and intracranial neoplasms. Much confusion surrounds the nomenclature of acute vestibular neuronitis because the term "labyrinthitis" often is used interchangeably with it. Labyrinthitis (i.e., inflammation of the labyrinthine organs caused by infection) is distinct from acute vestibular neuronitis (i.e., inflammation of the vestibular nerve), and the terms are not interchangable.1

SORT: KEY RECOMMENDATIONS FOR PRACTICE

Clinical recommendationsEvidencerating References Comments

Use the Dix-Hallpike maneuver to diagnose BPPV.

C 7, 10 The Dix-Hallpike maneuver has a positive predictive value of 83 percent and negative predictive value of 52 percent for the diagnosis of BPPV.

Do not use laboratory tests to initially identify the etiology of dizziness.

C 10 Laboratory tests identify the etiology of vertigo in less than 1 percent of patients with dizziness.

Consider radiologic studies in patients with neurologic signs and symptoms, risk factors for cerebrovascular disease, or progressive unilateral hearing loss.

C 19 -

Use MRI for diagnosing vertigo when neuroimaging is needed.

C 26 MRI is superior to computed tomography for the diagnosis of vertigo because of

its superior ability to visualize the posterior fossa.

BPPV = benign paroxysmal positional vertigo, MRI = magnetic resonance imaging.A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C =

consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, see page 196 or http://www.aafp.org/afpsort.xml.

Because patients with dizziness often have difficulty describing their symptoms, determining the cause can be challenging. An evidence-based approach using knowledge of key historic, physical examination, and radiologic findings for the causes of vertigo can help family physicians establish a diagnosis and consider appropriate treatments in most cases (Figure 1).

TABLE 1

Differential Diagnosis of Vertigo

Cause Description

Peripheral causes

Acute labyrinthitis Inflammation of the labyrinthine organs caused by viral orbacterial infection

Acute vestibular neuronitis (vestibular neuritis)*

Inflammation of the vestibular nerve, usually caused by viral infection

Benign positional paroxysmal vertigo (benign positional vertigo)

Transient episodes of vertigo caused by stimulation of vestibular sense organs by canalith; affects middle-age and older patients; affects twice as many women as men

Cholesteatoma Cyst-like lesion filled with keratin debris, most often involving the middle ear and mastoid

Herpes zoster oticus (Ramsay Hunt syndrome)

Vesicular eruption affecting the ear; caused by reactivation of the varicella-zoster virus

Ménière's disease (Ménière's syndrome, endolymphatic hydrops)

Recurrent episodes of vertigo, hearing loss, tinnitus, or auralfullness caused by increased volume of endolymph in the semicircular canals

Otosclerosis Abnormal growth of bone in the middle ear, leading to immobilization of the bones of conduction and a conductive hearing loss [corrected]

Perilymphatic fistula Breach between middle and inner ear often caused by trauma or excessive straining

Central causes

Cerebellopontine angletumor

Vestibular schwannoma (i.e., acoustic neuroma) as well as infratentorial ependymoma, brainstem glioma, medulloblastoma, or neurofibromatosis

Cerebrovascular diseasesuch as transient ischemic attack or stroke

Arterial occlusion causing cerebral ischemia or infarction, especially if affecting the vertebrobasilar system

Migraine Episodic headaches, usually unilateral, with throbbing accompanied by other symptoms such as nausea, vomiting, photophobia, or phonophobia; may be preceded by aura

Multiple sclerosis Demyelinization of white matter in the central nervous system

Other causes

Cervical vertigo Vertigo triggered by somatosensory input from head and neck movements

Drug-induced vertigo Adverse reaction to medications

Psychological Mood, anxiety, somatization, personality, or alcohol abuse disorders

*-Acute vestibular neuronitis often is erroneously called acute or viral labyrinthitis.Information from references 1 through 6.

 

Diagnosing Vertigo

FIGURE 1. Algorithm for an initial approach for diagnosing the cause of vertigo. (MRI = magnetic resonance imaging.)

History

History alone reveals the diagnosis in roughly three out of four patients complaining of dizziness, although the proportion in patients specifically complaining of vertigo is unknown.10 When collecting a patient's history, the physician first must determine whether the patient truly has vertigo versus another type of dizziness. This can be done by asking, "When you have dizzy spells, do you feel light-headed or do you see the world spin around you?" An affirmative answer to the latter part of this question has been shown to accurately detect patients with true vertigo.11

PERIPHERAL OR CENTRAL CAUSE OF VERTIGO

The next task is to determine whether the patient has a peripheral or central cause of vertigo. Key information from the history that can be used to make this distinction includes the timing and duration of the vertigo (Table 23,6,12); what provokes or aggravates it (Table 31,3,5,12,13); and whether any associated symptoms exist, especially neurologic symptoms and hearing loss (Tables 41,6,12-14 and 5 9,12,13).10 Characteristics distinguishing peripheral and central causes of vertigo are listed in Table 6.14,15 Rotatory illusions are highly associated with peripheral vestibular disorders, especially when nausea or vomiting accompanies the vertigo.1 Nystagmus in peripheral vertigo usually is horizontal and rotational, lessens or disappears when the patient focuses the gaze, and usually is triggered by some provoking factor. In central vertigo, nystagmus is purely horizontal, vertical, or rotational; does not lessen when the patient focuses the gaze; and persists for a longer period.14 The duration of each episode also has significant diagnostic value; generally, the longer symptoms last, the greater the likelihood that there is a central cause of vertigo.3 In one study,16 the presence of vertigo upon awakening in the morning was suggestive of peripheral vestibular disorders. Peripheral vertigo generally has a more sudden onset than vertigo of central nervous system origin, except for acute cerebrovascular events.3

TABLE 2

Typical Duration of Symptoms for Different Causes of Vertigo

Duration of episode Suggested diagnosis

A few seconds Peripheral cause: unilateral loss of vestibular function; late stages of acute vestibular neuronitis; late stages of Ménière's disease

Several secondsto a few minutes

Benign paroxysmal positional vertigo; perilymphatic fistula

Several minutesto one hour

Posterior transient ischemic attack;perilymphatic fistula

Hours Ménière's disease; perilymphatic fistula from trauma or surgery; migraine; acoustic neuroma

Days Early acute vestibular neuronitis*; stroke; migraine; multiple sclerosis

Weeks Psychogenic (constant vertigo lasting weeks without improvement)

*-Vertigo with early acute vestibular neuritis can last as briefly as two days or as long as one week or more.Information from references 3, 6, and 12.

TABLE 3

Provoking Factors for Different Causes of Vertigo

Provoking factor Suggested diagnosis

Changes in head position Acute labyrinthitis; benign positional paroxysmal vertigo; cerebellopontine angle tumor; multiple sclerosis; perilymphatic fistula

Spontaneous episodes (i.e., no consistentprovoking factors)

Acute vestibular neuronitis; cerebrovascular disease (stroke or transient ischemic attack); Ménière's disease; migraine; multiple sclerosis

Recent upper respiratory viral illness Acute vestibular neuronitis

Stress Psychiatric or psychological causes; migraine

Immunosuppression (e.g., immunosuppressive medications, advanced age, stress)

Herpes zoster oticus

Changes in ear pressure, head trauma, excessive straining, loud noises

Perilymphatic fistula

Information from references 1, 3, 5, 12, and 13.

 

TABLE 4

Associated Symptoms for Different Causes of Vertigo

Symptom Suggested diagnosis

Aural fullness Acoustic neuroma; Ménière's disease

Ear or mastoid pain Acoustic neuroma; acute middle ear disease (e.g., otitis media, herpes zoster oticus)

Facial weakness Acoustic neuroma; herpes zoster oticus

Focal neurologic findings

Cerebellopontine angle tumor; cerebrovascular disease; multiple sclerosis (especially findings not explained by single neurologic lesion)

Headache Acoustic neuroma; migraine

Hearing loss Ménière's disease; perilymphatic fistula; acoustic neuroma; cholesteatoma; otosclerosis; transient ischemic attack or stroke involving anterior inferior cerebellar artery; herpes zoster oticus

Imbalance Acute vestibular neuronitis (usually moderate); cerebellopontine angle tumor (usually severe)

Nystagmus Peripheral or central vertigo

Phonophobia, photophobia

Migraine

Tinnitus Acute labyrinthitis; acoustic neuroma; Ménière's disease

Information from references 1, 6, and 12 through 14.

 

TABLE 5

Causes of Vertigo Associated with Hearing Loss

Diagnosis Characteristics of hearing loss

Acoustic neuroma Progressive, unilateral, sensorineural

Cholesteatoma Progressive, unilateral, conductive

Herpes zoster oticus (i.e., Ramsay Hunt syndrome)

Subacute to acute onset, unilateral

Ménière's disease Sensorineural, initially fluctuating, initially affecting lower frequencies;

later in course: progressive, affecting higher frequencies

Otosclerosis Progressive, conductive

Perilymphatic fistula Progressive, unilateral

Transient ischemic attack orstroke involving anterior inferior cerebellar artery or internal auditory artery

Sudden onset, unilateral

Information from references 9, 12, and 13.

 

TABLE 6

Distinguishing Characteristics of Peripheral vs. Central Causes of Vertigo

Feature Peripheral vertigo Central vertigo

Nystagmus Combined horizontal and torsional; inhibited by fixation of eyes onto object; fades after a few days; does not change direction with gaze to either side

Purely vertical, horizontal, or torsional; not inhibited by fixation of eyes onto object; may last weeks to months; may change direction with gaze towards fast phase of nystagmus

Imbalance Mild to moderate; able to walk Severe; unable to stand still or walk

Nausea, vomiting May be severe Varies

Hearing loss, tinnitus Common Rare

Nonauditory neurologic symptoms

Rare Common

Latency following provocative diagnostic maneuver

Longer (up to 20 seconds) Shorter (up to 5 seconds)

Information from references 14 and 15.

SEVERITY

Knowing the severity of vertigo over time also is helpful. For example, in acute vestibular neuronitis, initial symptoms typically are severe but lessen over the next few days. In Ménière's disease, attacks of vertigo initially increase in severity, then lessen in severity later on. Patients complaining of constant vertigo lasting for weeks may have a psychological cause for their symptoms.

PROVOKING FACTORS

Provoking factors and circumstances around the onset of vertigo may prove useful in narrowing the differential diagnosis to a peripheral vestibular condition. If symptoms occur only with positional changes, such as turning over in bed,17 bending over at the waist and then straightening up, or hyperextending the neck, BPPV is the most likely cause.1 A recent viral upper respiratory infection may precede acute vestibular neuronitis or acute labyrinthitis. Factors that provoke migraine headaches can cause vertigo if the patient experiences this as a symptom associated with migraine.

Vertigo can be caused by perilymphatic fistula (i.e., breach between the inner ear and middle ear).18 Perilymphatic fistula may be caused by trauma from a direct blow, or from activities such as scuba diving (from barotrauma) and heavy weight bearing or excessive straining with bowel movements.3,12 Sneezing or

movements that place the affected ear downward also can provoke vertigo in patients with perilymphatic fistulas.19

The presence of Tullio's phenomenon (i.e., nystagmus and vertigo caused by loud noises or sounds at a particular frequency) suggests a peripheral cause for vertigo.12

Significant psychosocial stress can cause patients to complain of vertigo. Asking about psychological stressors or psychiatric history may be important, especially in patients whose history does not necessarily fit the usual presentation of physical causes of vertigo. For example, a history of anxiety or panic attacks associated with vertigo may point to hyperventilation as a cause.12

ASSOCIATED SYMPTOMS

Hearing loss, pain, nausea, vomiting, or neurologic symptoms can help differentiate the cause of vertigo. Most causes of vertigo with hearing loss are peripheral, the main exception being a cerebrovascular event involving the internal auditory artery or anterior inferior cerebellar artery. Pain accompanying vertigo may occur with acute middle ear disease, invasive disease of the temporal bone, or meningeal irritation.12 Vertigo often is associated with nausea or vomiting in acute vestibular neuronitis and in severe episodes of Ménière's disease and BPPV.1,20 In central causes of vertigo, nausea and vomiting tend to be less severe.14 Neurologic symptoms such as weakness, dysarthria, vision or hearing changes, paresthesia, altered level of consciousness, ataxia, or other changes in sensory and motor function favor the presence of a central cause of vertigo such as cerebrovascular disease, neoplasm, or multiple sclerosis. Patients with migrainous vertigo may experience other symptoms related to the migraine, including a typical headache (often throbbing, unilateral, sometimes preceded by an aura), nausea, vomiting, photophobia, and phonophobia. Twenty-one to 35 percent of patients with migraine suffer vertigo.21

MEDICAL HISTORY

Other important clues to the diagnosis of vertigo may come from the patient's medical history, including medications, trauma, or exposure to toxins.18 Age is associated with some underlying conditions that can cause vertigo. For example, older patients, especially those with diabetes or hypertension, are at higher risk of cerebrovascular causes of vertigo.12 Patients should be asked about family history including hereditary conditions such as migraine and risk factors for cerebrovascular disease.

Physical Examination

Physicians should pay particular attention to physical findings of the neurologic, head and neck, and cardiovascular systems.

NEUROLOGIC EXAMINATION

The cranial nerves should be examined for signs of palsies, sensorineural hearing loss, and nystagmus. Vertical nystagmus is 80 percent sensitive for vestibular nuclear or cerebellar vermis lesions.2 Spontaneous horizontal nystagmus with or without rotatory nystagmus is consistent with acute vestibular neuronitis. Patients with peripheral vertigo have impaired balance but are still able to walk, whereas patients with central vertigo have more severe instability and often cannot walk or even stand without falling.14 Although Romberg's sign is consistent with a vestibular or proprioceptive problem, it is not particularly useful in the diagnosis of vertigo. In one study,22 it was only 19 percent sensitive for peripheral vestibular disorders and did not correlate with more serious causes of dizziness (not limited to vertigo) such as drug-related dizziness, seizure, arrhythmia, or cerebrovascular events.

The Dix-Hallpike maneuver (Figure 2)1,3,19 may be the most helpful test to perform on patients with vertigo. It has a positive predictive value of 83 percent and a negative predictive value of 52 percent for the diagnosis of BPPV.7,10 After the initial test, the intensity of induced symptoms typically wanes with repeated maneuvers in peripheral vertigo but does so less often in central vertigo.15 The combination of a positive Dix-Hallpike maneuver and a history of vertigo or vomiting suggests a peripheral vestibular disorder.22 If the maneuver provokes purely vertical (usually downbeat) or torsional nystagmus without a latent period of at least a few seconds, and does not wane with repeated maneuvers, this suggests a central cause for vertigo such as a posterior fossa tumor or hemorrhage.14,15

FIGURE 2. To perform the Dix-Hallpike maneuver, the patient initially sits upright. The examiner should warn the

patient that the maneuver may provoke vertigo. The examiner turns the patient's head 30 to 45 degrees to the side

being tested (A). The patient keeps his or her eyes open and focused on the examiner's eyes or forehead. Then, as

the examiner supports the patient's head, the patient quickly lies supine (within two seconds), allowing the neck to

hyperextend slightly and hang off the edge of the examining table 20 to 30 degrees past horizontal (B). After a two- to

20-second latent period, the onset of torsional upbeat or horizontal nystagmus denotes a positive test for benign

paroxysmal positional vertigo. The episode can last 20 to 40 seconds. Nystagmus changes direction when the patient

sits upright again.Information from references 1, 3, and 19.

Hyperventilation for 30 seconds may assist in ruling out psychogenic causes of vertigo associated with hyperventilation syndrome.22 It rarely can cause true vertigo in patients with perilymphatic fistulas or acoustic neuromas.12

HEAD AND NECK EXAMINATION

The tympanic membranes should be examined for vesicles (i.e., herpes zoster oticus [Ramsay Hunt syndrome]) or cholesteatoma. Hennebert's sign (i.e., vertigo or nystagmus caused by pushing on the tragus and external auditory meatus of the affected side) indicates the presence of a perilymphatic fistula.12

Pneumatic otoscopy may cause similar findings.3 The Valsalva maneuver (i.e., forced exhalation with nose plugged and mouth closed to increase pressure against the eustachian tube and inner ear) may cause vertigo in patients with perilymphatic fistulae12 or anterior semicircular canal dehiscence12,23; its clinical diagnostic value, however, is limited.22

CARDIOVASCULAR EXAMINATION

Orthostatic changes in systolic blood pressure (e.g., a drop of 20 mm Hg or more) and pulse (e.g., increase of 10 beats per minute) in patients with vertigo upon standing may identify problems with

dehydration or autonomic dysfunction.10 Carotid sinusstimulation should not be performed; it has been shown to be not useful diagnostically22 and potentially is dangerous.

Laboratory Evaluation

Laboratory tests such as electrolytes, glucose, blood counts, and thyroid function tests identify the etiology of vertigo in fewer than 1 percent of patients with dizziness.10 They may be appropriate when patients with vertigo exhibit signs or symptoms that suggest the presence of other causative conditions. Audiometry helps establish the diagnosis of Ménière's disease.20

Radiologic Studies

Physicians should consider neuroimaging studies in patients with vertigo who have neurologic signs and symptoms, risk factors for cerebrovascular disease, or progressive unilateral hearing loss.19 In one study,24 40 percent of patients with dizziness and neurologic signs had relevant abnormalities suggesting central nervous system lesions on magnetic resonance imaging of the head. In patients with isolated vertigo who also were at risk for cerebrovascular disease, 25 percent had caudal cerebellar infarcts.25 In general, magnetic resonance imaging is more appropriate than computed tomography for diagnosing vertigo because of its superiority in visualizing the posterior fossa, where most central nervous system disease that causes vertigo is found.26 Magnetic resonance or conventional angiography of the posterior fossa vasculature may be useful in diagnosing vascular causes of vertigo such as vertebrobasilar insufficiency, thrombosis of the labyrinthine artery, anterior or posterior inferior cerebellar artery insufficiency, and subclavian steal syndrome.26

Neuroimaging studies can be used to rule out extensive bacterial infections, neoplasms, or developmental abnormalities if other symptoms suggest one of those diagnoses.26,27 However, they are not indicated in patients who have BPPV,26 usually are not necessary to diagnose acute vestibular neuronitis or Ménière's disease, and are poor routine screening tests for cerebellopontine angle tumors causing vertigo.27

Conventional radiographs or cross-sectional imaging procedures may aid in the diagnosis of cervical vertigo (i.e., vertigo triggered by somatosensory input from head and neck movements) in patients with a history suggestive of this diagnosis26; however, the existence of this disorder remains controversial, and most patients in whom this diagnosis is considered should have other, more well-established conditions investigated.4

Referral

Not all patients with vertigo need to be referred to a subspecialist. Family physicians should consider referral to the appropriate subspecialist (e.g., otolaryngologist, head and neck surgeon, neurologist, neurosurgeon) if the diagnosis of vertigo is unclear or if the patient has a medical problem requiring further subspecialty care.

Members of various family medicine departments develop articles for "Problem-Oriented Diagnosis." This is one in a series from the Department of Family Medicine at the University of Southern California, Los Angeles. Coordinator of the series is Ricardo G. Hahn, M.D.

The author thanks Lyndee Knox, Ph.D., for assistance with the preparation of the manuscript.

This is a corrected version of the article that appeared in print.

Treatment of VertigoVertigo is the illusion of motion, usually rotational motion. As patients age, vertigo becomes an increasingly common presenting complaint. The most common causes of this condition are benign paroxysmal positional vertigo, acute vestibular neuronitis or labyrinthitis, Ménière's disease, migraine, and anxiety disorders. Less common causes include vertebrobasilar ischemia and retrocochlear tumors. The distinction between peripheral and central vertigo usually can be made clinically and guides management decisions. Most patients with vertigo do not require extensive diagnostic testing and can be treated in the primary care setting. Benign paroxysmal positional vertigo usually improves with a canalith repositioning procedure. Acute vestibular neuronitis or labyrinthitis improves with initial stabilizing measures and a vestibular suppressant medication, followed by vestibular rehabilitation exercises. Ménière's disease often responds to the combination of a low-salt diet and diuretics. Vertiginous migraine headaches generally improve with dietary changes, a tricyclic antidepressant, and a beta blocker or calcium channel blocker. Vertigo associated with anxiety usually responds to a selective serotonin reuptake inhibitor. (Am Fam Physician 2005;71:1115-22, 1129-30. Copyright© 2005 American Academy of Family Physicians.)

Vertigo, a type of dizziness, is the illusion of motion, usually rotational motion. Associated symptoms

include nausea, emesis, and diaphoresis. Vertigo should be distinguished from other types of dizziness, such as imbalance (dysequilibrium) and lightheadedness (presyncope). Most cases of vertigo can be diagnosed clinically and managed in the primary care setting.

Vestibular Function and Vertigo

Vertigo results from acute unilateral vestibular lesions that can be peripheral (labyrinth or vestibular nerve) or central (brainstem or cerebellum). In contrast, tumors and ototoxic medications produce slowly progressive unilateral or bilateral lesions. Lesions that progress slowly or processes that affect both vestibular apparatuses equally usually do not result in vertigo.

Diagnosis of Vertigo

In patients with vertigo, the neurologic examination should include the Dix-Hallpike maneuver to

differentiate peripheral from central vertigo.

Because vertigo can have multiple concurrent causes (especially in older patients), a specific diagnosis can be elusive. The duration of vertiginous episodes and the presence or absence of auditory symptoms can help narrow the differential diagnosis (Table 1).1 Psychiatric disorders, motion sickness, serous otitis media, cerumen impaction, herpes zoster, and seizure disorders also can present with dizziness.

The physical examination should include measurements of orthostatic vital signs and an otoscopic examination. The neurologic examination should include the Dix-Hallpike maneuver to differentiate peripheral from central vertigo2,3 (Figure 1 and Table 23,4).

Strength of Recommendations

Key clinical recommendation Label References

The canalith repositioning procedure (Epley maneuver) is recommended in patients with benign paroxysmal positional vertigo.

A 18, 19, 20

The modified Epley maneuver also is effective in patients with benign paroxysmal positional vertigo.

B 16

Vestibular suppressant medication is recommended for symptom relief in patients with acute vestibular neuronitis.

C 6, 7, 8

Vestibular exercises are recommended for more rapid and complete vestibular compensation in patients with acute vestibular neuronitis.

B 14

Treatment with a low-salt diet and diuretics is recommended for patients with Ménière's disease and vertigo.

B 23, 24, 25

Effective treatments for vertiginous migraine include migraine prophylaxis (e.g., tricyclic antidepressants, beta blockers, calcium channel blockers), migraine-abortive medications (e.g., sumatriptan [Imitrex]), and vestibular rehabilitation exercises.

B 13, 30, 31, 32

Selective serotonin reuptake inhibitors can relieve vertigo in patients with anxiety disorders. Because of side effects, slow titration is recommended.

B 34

A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, opinion, or case series. See page 1046 for more information.

No laboratory testing is absolutely indicated in the work-up of patients with vertigo. If hearing loss is suspected, complete audiometric testing can help distinguish vestibular pathology from retrocochlear pathology (e.g., acoustic neuroma).

Brain imaging is warranted if a tumor or stroke is suspected. The American College of Radiology5 recommends magnetic resonance imaging with contrast medium when a patient presents with acute vertigo and sensorineural hearing loss. Magnetic resonance angiography can be used to evaluate the vertebrobasilar circulation.

General Treatment PrinciplesMEDICATIONS

Medications are most useful for treating acute vertigo that lasts a few hours to several days (Table 3).6,7 They have limited benefit in patients with benign paroxysmal positional vertigo, because the vertiginous episodes usually last less than one minute. Vertigo lasting more than a few days is suggestive of permanent vestibular injury (e.g., stroke), and medications should be stopped to allow the brain to adapt to new vestibular input.

A wide variety of medications are used to treat vertigo and the frequently concurrent nausea and emesis. These medications exhibit various combinations of acetylcholine, dopamine, and histamine receptor antagonism. The American Gastroenterological Association recommends anticholinergics and antihistamines for the treatment of nausea associated with vertigo or motion sickness.8

TABLE 1

Differential Diagnosis of Vertigo

DisorderDuration of

episodesAuditory

symptoms PrevalencePeripheral or central

vertigo

Benign paroxysmal positional vertigo Seconds No Common Peripheral

Perilymphatic fistula (head trauma, Seconds Yes Uncommon Peripheral

barotrauma)

Vascular ischemia: transient ischemic attack Seconds to hours Usually not Uncommon Central or peripheral*

Ménière's disease Hours Yes Common Peripheral

Syphilis Hours Yes Uncommon Peripheral

Vertiginous migraine Hours No Common Central

Labyrinthine concussion Days Yes Uncommon Peripheral

Labyrinthitis Days Yes Common Peripheral

Vascular ischemia: stroke Days Usually not Uncommon Central or peripheral*

Vestibular neuronitis Days No Common Peripheral

Anxiety disorder Variable Usually not Common Unspecified

Acoustic neuroma Months Yes Uncommon Peripheral

Cerebellar degeneration Months No Uncommon Central

Cerebellar tumor Months No Uncommon Central

Multiple sclerosis Months No Uncommon Central

Vestibular ototoxicity Months Yes Uncommon Peripheral

*-Vertigo can be caused by vascular ischemia in the central vertebrobasilar circulation or the peripheral circulation to the vestibular nerve and labyrinth.1

Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the vestibular system.6 Benzodiazepines enhance the action of GABA in the central nervous system (CNS) and are effective in relieving vertigo and anxiety.

Older patients are at particular risk for side effects of vestibular suppressant medications (e.g., sedation, increased risk of falls, urinary retention). These patients also are more likely to experience drug interactions (i.e., additive effects with other CNS depressants).

TABLE 2

Clues to Distinguish Between Peripheral and Central Vertigo

Clues Peripheral vertigo Central vertigo

Findings on Dix-Hallpike maneuver    

Latency of symptoms and nystagmus

2 to 40 seconds None

Severity of vertigo Severe Mild

Duration of nystagmus Usually less than 1 minute Usually more than 1 minute

Fatigability* Yes No

Habituation† Yes No

Other findings    

Postural instability Able to walk; unidirectional instability

Falls while walking; severe instability

Hearing loss or tinnitus Can be present Usually absent

Other neurologic symptoms Absent Usually present

*-Response remits spontaneously as position is maintained.†-Attenuation of response as position repeatedly is assumed.

Information from references 3 and 4.

VESTIBULAR REHABILITATION EXERCISES

Vestibular rehabilitation exercises commonly are included in the treatment of vertigo9,10 (see patient information handout). These exercises train the brain to use alternative visual and proprioceptive cues to maintain balance and gait. It is necessary for a patient to reexperience vertigo so that the brain can adapt to a new baseline of vestibular function. After acute stabilization of the patient with vertigo, use of vestibular suppressant medications should be minimized to facilitate the brain's adaptation to new vestibular input.

A randomized, controlled trial (RCT)11 of 143 primary care patients with dizziness and vertigo showed that vestibular rehabilitation exercises improved nystagmus, postural control, movement-provoked dizziness, and subjective indexes of symptoms and distress. Another RCT12 evaluated the effectiveness of home vestibular rehabilitation in patients with chronic vertigo with a peripheral vestibular etiology. This trial12 showed a significant reduction of vertigo and an increase in the ability to perform activities of daily living independently.

Figure 1. Dix-Hallpike maneuver (used to diagnose benign paroxysmal positional vertigo). This test consists of a series of two maneuvers: With the patient sitting on the examination table, facing forward, eyes open, the physician turns the patient's head 45 degrees to the right (A). The physician supports the patient's head as the patient lies back quickly from a sitting to supine position, ending with the head hanging 20 degrees off the end of the examination table. The patient remains in this position for 30 seconds (B). Then the patient returns to the upright position and is observed for 30 seconds. Next, the maneuver is repeated with the patient's head turned to the left. A positive test is indicated if any of these maneuvers provide vertigo with or without nystagmus.

A retrospective case series13 assessed the efficacy of physical therapy in patients who had vestibular and balance disorders with or without a history of migraine. Both groups showed significant alleviation of dizziness and improvement of balance and gait. Vestibular exercises also have been shown to improve postural control during the first month after acute unilateral vestibular lesions resulting from vestibular neuronitis.14

Treatment of Specific DisordersBENIGN PAROXYSMAL POSITIONAL VERTIGO

Benign paroxysmal positional vertigo is caused by calcium debris in the semicircular canals (canalithiasis), usually the posterior canal. Medications generally are not recommended for the treatment of this condition.

The vertigo improves with head rotation maneuvers that displace free-moving calcium deposits back to the vestibule. Maneuvers include the canalith repositioning procedure or Epley maneuver15 and the modified Epley maneuver16 (Figure 2). The modified Epley maneuver can be performed at home.

TABLE 3

Medications Commonly Used In Patients with Acute Vertigo and Associated Nausea and Emesis

Medication Dosage Sedation Antiemesis Pregnancy category

Meclizine* (Antivert) 12.5 to 50 mg orally every 4 to 8 hours ++ + B

Dimenhydrinate* (Dramamine) 25 to 100 mg orally, IM, or IV every 4 to 8 hours

+ ++ B

Diazepam (Valium) 2 to 10 mg orally or IV every 4 to 8 hours ++ + D

Lorazepam (Ativan) 0.5 to 2 mg orally, IM, or IV every 4 to 8 hours

++ + D

Metoclopramide(Reglan)

5 to 10 mg orally every 6 hours5 to 10 mg by slow IV every 6 hours

+ +++ B

Prochlorperazine (Compazine) 5 to 10 mg orally or IM every 6 to 8 hours25 mg rectally every 12 hours5 to 10 mg by slow IV over 2 minutes

+ +++ C

Promethazine (Phenergan)

12.5 to 25 mg orally, IM, or rectally every4 to 12 hours

+++ ++ C

*-Available over the counter.

+ = mild; ++ = moderate; +++ = prominent; IM = intramuscular; IV = intravenous.

Information from references 6 and 7.

Patients may need to remain upright for 24 hours after canalith repositioning to prevent calcium deposits from returning to the semicircular canals, although this measure is not universally recommended. Contraindications to canalith repositioning procedures include severe carotid stenosis, unstable heart

disease, and severe neck disease, such as cervical spondylosis with myelopathy or advanced rheumatoid arthritis.17

Canalith repositioning has been found to be effective in patients with benign paroxysmal positional vertigo. The initial report15 on the Epley maneuver indicated an 80 percent success rate after a single treatment and a 100 percent success rate with repeated treatments. Two subsequent RCTs18,19 reported success rates of 50 to 90 percent. A Cochrane systematic review20 concluded that the Epley maneuver is a safe treatment that is likely to result in improvement of symptoms and conversion from a positive to negative Dix-Hallpike maneuver. However, the review20 noted that no long-term assessment was performed in either RCT18,19 on the use of the Epley maneuver. A study16 of 54 patients with benign paroxysmal positional vertigo found that the modified Epley maneuver was effective in resolving vertigo symptoms after one week of treatment. This study, however, has been criticized for inadequate randomization and lack of blinding of outcome assessors (patient self-report of symptoms).20

One study21 on the long-term effects of canalith repositioning procedures in patients with benign paroxysmal positional vertigo reported a recurrence rate of about 15 percent per year. Another study22 reported recurrence rates of 20 percent at 20 months and 37 percent at 60 months.

VESTIBULAR NEURONITIS AND LABYRINTHITIS

Acute inflammation of the vestibular nerve is a common cause of acute, prolonged vertigo. Associated hearing loss occurs if the labyrinth is involved. The vertigo usually lasts a few days and resolves within several weeks. Many cases of vestibular neuronitis or labyrinthitis are attributed to self-limited viral infections,7 although specific proof of a viral etiology rarely is identified.1

Treatment focuses on symptom relief using vestibular suppressant medications,6-8 followed by vestibular exercises.14 Vestibular compensation occurs more rapidly and more completely if the patient begins twice-daily vestibular rehabilitation exercises as soon as tolerated after the acute vertigo has been alleviated with medications.7,11

MÉNIÈRE'S DISEASE

Ménière's disease (or endolymphatic hydrops) presents with vertigo, tinnitus (low tone, roaring, or blowing quality), fluctuating low-frequency sensorineural hearing loss, and a sense of fullness in the ear. In this disorder, impaired endolymphatic filtration and excretion in the inner ear leads to distention of the endolymphatic compartment.

Treatment lowers endolymphatic pressure. Although a low-salt diet (less than 1 to 2 g of salt per day) and diuretics (most commonly the combination of hydrochlorothiazide and triamterene [Dyazide]) often reduce the vertigo, these measures are less effective in treating hearing loss and tinnitus.23,24 Note, however, that the authors of a systematic review25 of treatments for Ménière's disease criticized the statistical analysis of the frequency of vertigo episodes in one of the studies.23

In rare cases, surgical intervention, such as decompression with an endolymphatic shunt or cochleosacculotomy, may be required when Ménière's disease is resistant to treatment with diet and diuretics. Ablation of the vestibular hair cells with intratympanic injection of gentamicin also may be effective.26 Surgery usually is reserved for patients with severe, refractory Ménière's disease.

Figure 2. Epley maneuver. The patient sits on the examination table, with eyes open and head turned 45 degrees to the right (A). The physician supports the patient's head as the patient lies back quickly from a sitting to supine position, ending with the head hanging 20 degrees off the end of the examination table (B). The physician turns the patient's head 90 degrees to the left side. The patient remains in this position for 30 seconds (C). The physician turns the patient's head an additional 90 degrees to the left while the patient rotates his or her body 90 degrees in the same direction. The patient remains in this position for 30 seconds (D). The patient sits up on the left side of the examination table. (E) The procedure may be repeated on either side until the patient experiences relief of symptoms.

VASCULAR ISCHEMIA

The sudden onset of vertigo in a patient with additional neurologic symptoms (e.g., diplopia, dysarthria, dysphagia, ataxia, weakness) suggests the presence of vascular ischemia.

Treatment of transient ischemic attack and stroke includes preventing future events through blood pressure control, cholesterol-level lowering, smoking cessation, inhibition of platelet function (e.g., aspirin, clopidogrel [Plavix], aspirin-dipyridamole [Aggrenox]) and, possibly, anticoagulation (warfarin [Coumadin]).

Acute vertigo caused by a cerebellar or brainstem stroke is treated with vestibular suppressant medication and minimal head movement for the first day. As soon as tolerated, medication should be tapered, and vestibular rehabilitation exercises should be initiated.8,10

Placement of vertebrobasilar stents may be considered in a patient with symptomatic critical vertebral artery stenosis that is refractory to medical management.27 Rarely, infarction or hemorrhage in the cerebellum or brainstem may present with acute vertigo as the only neurologic symptom.28 Given the risk of brainstem compression with a large cerebellar stroke, neurosurgical decompression may be indicated.

MIGRAINE HEADACHES

Epidemiologic evidence shows a strong association between vertigo and migraine.29 Diagnostic criteria have been proposed to provide a more specific definition of vertiginous migraine.29 Diagnostic accuracy is important because vertiginous migraine may respond better to migraine treatments than to other interventions.

One retrospective review30 found that migraine treatments were effective in about 90 percent of patients with migraine-associated vertigo. Treatments included dietary changes (i.e., reduction or elimination of aspartame, chocolate, caffeine, or alcohol), lifestyle changes (i.e., exercise, stress reduction, improvements in sleep patterns), vestibular rehabilitation exercises, and medications (e.g., benzodiazepines, tricyclic antidepressants, beta blockers, selective serotonin reuptake inhibitors [SSRIs], calcium channel blockers, antiemetics).

Another retrospective chart review31 demonstrated that stepwise treatment of migraine-associated dizziness (vertigo or dysequilibrium) resulted in complete or dramatic reduction of symptoms in 58 of 81 patients (72 percent). The stepwise treatment consisted of initiating dietary changes, then adding nortriptyline (Pamelor) if needed, then adding atenolol or a calcium channel blocker if needed and, finally, consultation with a neurologist if needed.

A survey32 of 53 patients with migraine at a university-based headache clinic found that the efficacy of medications in treating migraine-associated dizziness was directly correlated with their ability to alleviate migraines. This correlation was strongest in patients with vertigo who were receiving migraine-abortive medications (most significantly, sumatriptan [Imitrex]).

PSYCHIATRIC DISORDERS

Vertigo commonly is associated with anxiety disorders (e.g., panic disorder, generalized anxiety disorder) and, less frequently, depression.33,34 Hyperventilation usually occurs and can result in hypocapnia with reversible cerebral vasoconstriction. Hyperventilation and hypocapnia may be accompanied by dyspnea, chest pain, palpitations, or paresthesias.

Subclinical vestibular dysfunction has been measured in patients with anxiety disorders or depression, most commonly panic disorder with moderate to severe agoraphobia.33 Conversely, classic vertigo resulting from more ostensible vestibular pathology usually induces severe anxiety symptoms and thus can be hard to distinguish from a primary anxiety disorder.

Vestibular suppressants and benzodiazepines most frequently are used to treat dizziness that is associated with anxiety disorder, but these medications provide only transient or inadequate relief.34 SSRIs such as

citalopram (Celexa), fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft) may provide better relief.

A review34 of 68 patients from a research database at a university neurotology center evaluated open-label SSRI treatment of dizziness associated with psychiatric symptoms (with or without neurotologic illness). Significant improvement of dizziness occurred in 38 patients (63 percent); however, 15 (25 percent) of the 60 patients experienced intolerable side effects. Because some side effects of SSRIs (e.g., nausea, sedation, dizziness) may be more intolerable for patients who have dizziness in association with psychiatric symptoms, slow titration should be used.34

Other medications that are effective in patients with anxiety disorders or depression, such as norepinephrine-serotonin reuptake inhibitors (e.g., venlafaxine [Effexor]) and tricyclic antidepressants (e.g., nortriptyline, desipramine [Norpramin]), have not been evaluated in patients with concomitant vertigo.

Nonpharmacologic treatments for anxiety disorders, such as cognitive behavior therapy, may be helpful. A small prospective RCT of vestibular rehabilitation combined with cognitive behavior therapy to reduce anxiety in older patients with dizziness showed that this combination of treatments improved gait speed and dizziness symptoms but did not improve anxiety or depression.35

PHYSIOLOGIC VERTIGO

Motion sickness9 is attributed to an incongruence in the sensory input from the vestibular, visual, and somatosensory systems. Motion sickness occurs while riding in a car, boat, or airplane if the vestibular and somatosensory systems sense movement, but the visual system does not.

On the first sensation of motion sickness, efforts should be made to bring vestibular, visual, and somatosensory input back in congruence. For example, a person on a boat who starts to feel seasick should immediately watch the horizon. Seasickness can be prevented by applying a scopolamine patch (Transderm-Scop) behind one ear at least four hours before boating.8,36

The authors indicate that they do not have any conflicts of interest. Sources of funding: none reported.

Members of various family medicine departments develop articles for "Practical Therapeutics." This article is one in a series coordinated by the Department of Family Medicine and Preventive Medicine at the University of California, San Diego, School of Medicine. Guest editor of the series is Tyson Ikeda, M.D.

Inner Ear, Evaluation of DizzinessFeb 11, 2008

History

In the evaluation of a patient who experiences dizziness, the examiner's initial efforts must be directed at determining the exact nature of the patient's symptoms because the pathophysiology determines the patient's sensations. Precisely understanding the symptoms determines the workup. For example, in a patient with syncope or presyncope, the cause of the sensation is probably cardiovascular and not inner ear. In contrast, in

a patient with a sensation of spinning or whirling, the pathology probably involves the inner ear or vestibular nerve on one side, although insults to the cerebellum and brainstem may also produce true vertigo. Therefore, the cause in a patient with true vertigo cannot be assumed to be peripheral.

Although close questioning and careful examination usually reveal important differences, conditions such as multiple sclerosis, migraine equivalent, and vertebrobasilar transient ischemic episodes may simulate peripheral vestibulopathy. Vertigo, the hallmark of inner ear disease, is defined as the illusion of movement of either one's self or one's environment. An assessment of the patient's current history should address the following:

Ask the patient to describe the symptoms without using the word dizzy. Have the patient differentiate vertigo from presyncope or near-syncope.

Determine if the patient has a sense of being pushed down or pushed to 1 side (pulsion). A peculiar sense of movement of objects viewed when the patient moves is termed oscillopsia.

Ascertain whether the symptoms are related to an anxiety episode; patients with agoraphobia may describe their symptoms as dizziness.

Determine if the sensation is continuous or episodic; if episodic, find out if the sensation is fleeting or prolonged.

Ascertain whether the onset and progression of symptoms were slow and insidious or acute.

Ask the patient about head trauma and other illnesses to determine the setting of the initial symptoms. Trauma resulting in damage to an ear often manifests as unilateral hearing loss, which may be the cause of episodic vertigo even years later (posttraumatic hydrops).

Determine if the episodes are associated with turning the head, lying supine, or sitting upright.

Determine if symptoms of an upper respiratory infection or flu-like illness preceded the onset of vertigo.

Inquire about associated symptoms such as hearing loss or tinnitus (ringing in the ears), aural fullness, diaphoresis, nausea, or emesis.

Determine if the patient has an aura or warning before the symptoms start.

If hearing loss is evident, find out if hearing fluctuates.

Determine if the patient has a headache or visual symptoms such as scintillating scotoma.

Ask the patient about brainstem symptoms such as diplopia, dysarthria, facial paresthesia, or extremity numbness or weakness.

Ascertain the degree of impairment during an episode.

Inquire about exposure to ototoxic medications, such as aminoglycosides and antineoplastic drugs (especially cisplatin). These medications can damage vestibular hair cells and typically lead to progressive ataxia and/or oscillopsia. Because ototoxic medications simultaneously affect both labyrinths, they rarely cause vertigo. When ototoxic patients describe vertigo, the condition almost always is related to head movement and is described as an uncomfortable sense of shifting or bobbing of viewed objects (oscillopsia).

In obtaining the medical history, include the following:

Determine if the patient has conditions such as diabetes (which can cause visual and proprioceptive problems), hypertension, cardiovascular or cerebrovascular disease, migraine, or neurologic disease (eg, multiple sclerosis).

Determine if the patient has any family history of cardiovascular disease, peripheral vascular disease, or migraine. Labyrinthine causes of vertigo usually are not inherited; however, rare exceptions (eg, Usher syndrome) are reported. Some clinical researchers believe that Ménière disease may have a hereditary predilection.

Inquire about the patient's medications. The list of medications that can cause dizziness is long; the most common culprits are antihypertensive agents. Ask if the onset of the patient's symptoms was associated with starting a new medication or a change in the dose or frequency of a medication.

Determine if the patient has had ear surgery. Although surgery for chronic ear disease only occasionally results in permanent vestibular injury, patients with a history of surgery for cholesteatoma may have an iatrogenic or acquired labyrinthine fistula. Patients who have undergone stapes surgery for otosclerosis or tympanosclerosis may develop vestibular symptoms because of perilymphatic fistula, adhesions between the oval window and saccule, or an overly long prosthesis.

Examination of Associated Systems

Perform a complete examination of pertinent systems, such as the cardiovascular and neurologic systems (especially cranial nerves), before proceeding to specific office tests of the vestibular system. For example, if a patient experiences presyncope, perform auscultation of the heart and cervical vessels, and determine orthostatic blood pressure and pulse. Examine the ears for a retracted or perforated tympanic membrane or cholesteatoma. Assess hearing in both ears.

Office Examination of the Vestibular System

Balance involves the overlapping function of several systems, namely, the visual system, the proprioceptive system, and the vestibular system. Together, these systems maintain equilibrium. Although many of the office-based tests described below incorporate this triad of sensory systems, most tests concern the vestibular system.

The primary goal of the vestibular system is to limit the slippage of images on the retina during head movement. Slippage of images greater than 2-3° per second blurs visual acuity. The 3 systems that are involved in limiting retinal slip are (1) the smooth-pursuit system, (2) the optokinetic system (which work best at relatively low head velocities), and (3) the vestibulo-ocular reflex (VOR) system. In the VOR system, the semicircular canals are angular accelerometers, and the otolithic organs are linear accelerometers. Because most human movements are brisk (0.6-8.2 Hz, or <90° per second during walking to <170° per second during running), the human vestibular system has evolved into a transducer of rapid head movement, an observation that is reflected in many of the tests.

For patients whose symptoms are episodic, physical examination findings may be normal between episodes. Furthermore, because the patient often can suppress nystagmus caused by a peripheral vestibulopathy, many of the vestibulo-oculomotor tests in the office examination are performed with +20 lenses (ie, cataract glasses), which prevent the patient from focusing on objects in the visual surround.

Specific Office Tests of Balance

Gait test

Determine whether the patient staggers or consistently leans to 1 side or the other.

Oculomotor examination

Assess for an internuclear ophthalmoplegia and gaze-dependent nystagmus. Nystagmus of peripheral (ie, labyrinthine) origin typically is unidirectional. Looking in the direction of the fast phase of nystagmus and preventing visual fixation with +20 lenses exaggerate the nystagmus.

Nystagmus of brainstem or cerebellar (ie, central) origin may be bidirectional and have more than one direction, eg, torsional plus horizontal movement. Pure vertical nystagmus almost always is a sign of brainstem disease and not a labyrinthine disorder.

Station (Romberg)

The Romberg test originally was described as a test for tabes dorsalis. The sharpened Romberg test is having the patient stand heel to toe with 1 foot in front of the other; this test is required to detect abnormalities in younger patients.

Fukuda test (stepping test of Unterberger)

The patient is asked to step in place for 20-30 seconds. Rotation of the patient may indicate a unilateral loss of vestibular tone.

Dix-Hallpike maneuver

The Dix-Hallpike maneuver is one of the most important tests for patients who experience true vertigo. This test involves having the patient lie back suddenly with the head turned to one side. The test results are considered abnormal if the patient reports vertigo and exhibits a characteristic torsional (ie, rotary) nystagmus that starts a few seconds after the patient lies back (latency), lasts 40-60 seconds, reverses when the patient sits up, and fatigues with repetition (see Benign Paroxysmal Positional Vertigo).

Head-shake test

The examiner vigorously shakes (approximately 1 Hz) the patient's head in the horizontal plane from side to side for 10-15 seconds. The patient is wearing +20 lenses to inhibit visual fixation. After the shaking is stopped, the eyes are observed for nystagmus. This test can reveal latent nystagmus and indicate which labyrinth is malfunctioning. By convention, the fast phase of nystagmus is the terminology used to describe nystagmus. In this test, the fast phase of nystagmus is directed toward the normal (or better-performing) labyrinth.

Head-thrust test

The patient is asked to gaze steadily at a target in the room. The examiner briskly moves the patient's head from one side to the other while observing eye position. A normal result is obtained when the patient's eyes remain fixed on the target. When the eyes make a compensatory movement after the head is stopped to reacquire the target (a refixation saccade), the test results are abnormal. This test can indicate if the output of one or both labyrinths is depressed.

Oscillopsia test

Before and during vigorous head shaking, the patient is asked to read the smallest visible line on the Snellen eye chart. A normal result is the ability to maintain acuity within 2 lines of the acuity at rest. Oscillopsia is the result of bilateral vestibulopathy, which most commonly is observed in ototoxicity.

Fistula test

The fistula test is designed to elicit symptoms and signs of an abnormal connection (fistula) between the labyrinth and surrounding spaces. Fistulas may be acquired, most commonly as a result of cholesteatoma or, less commonly, as a dehiscence of bone overlying the superior semicircular canal. Iatrogenic causes include chronic ear surgery and stapes surgery.

The test involves the application of pressure to the patient's ear canal and observation of eye movements with Frenzel lenses in place. Occluding the ear canal with the patient's tragus or using a Bruening otoscope can provide pressure to the ear canal. The direction of nystagmus depends on the site of the fistula, a topic that is beyond the scope of this article.

Carefully examine the cranial nerves, especially cranial nerves V and VII.

Laboratory Examination of the Vestibular System

The following tests commonly are performed to evaluate patients with vertigo.

Electronystagmography with caloric testing

This test has 2 parts, namely, oculomotor testing (pursuit and saccades) and caloric testing. Eye position is monitored by using electro-oculography, which relies on the dipole of the eye. In caloric testing, the ear canals are irrigated with water or air that is 7°C above or below body temperature. The goal of the test is to determine if significant asymmetry is present in the response of the labyrinths, which can indicate peripheral vestibular disease. Evidence of CNS disorders also can be identified on electronystagmography.

The caloric test may be helpful in determining the side of the lesion; however, it has several significant limitations. First, the test has a relatively poor reliability; test-retest values change markedly in the same patient. Second, the test can be used to examine only a small portion of the balance system (ie, the lateral canals) through a small range of frequencies. Hence, results of the test may not be generalized to the entire labyrinthine function of the tested subject.

Rotational chair testing

This test involves sinusoidally rotating the subject in a darkened booth while eye position is monitored to assess the VOR. By comparing eye velocity to head velocity (ie, velocity of the chair), one can determine VOR gain. The phase lead of the response and any asymmetry in the response can also be determined.

Vestibular autorotation testing

Because rotational chair testing requires expensive and cumbersome equipment, the vestibular autorotation test (VAT) has been developed to allow evaluation of the VOR. Also, commercially available rotational chairs allow testing at only modest head frequencies, typically less than 1 Hz, whereas VAT allows evaluation of the VOR at higher and more physiologically significant frequencies. The most commonly used system for VAT testing is from Western Systems Research, Inc. (Pasadena, CA).

The test is performed by using a computer-generated metronome to which the patient moves his or her head for an 18-second trial period at frequencies from 2-6 Hz. Because high head frequencies are tested, smooth pursuit contributes little to the response, and the test can be conducted in a lighted room while the patient fixates on a stationary target. This test can evaluate both the vertical and horizontal VOR.

The best use of the test may be in monitoring the VOR in patients who receive vestibulotoxic agents. The portability of the equipment allows bedside testing of hospitalized patients. The test/retest reliability of the test has been debated in the literature; therefore, it has not been adopted universally as a standard test of VOR function.

Computerized platform posturography

The tests described thus far address only 1 limb of the complex sensory and motor interactions required to maintain balance. Because the maintenance of equilibrium involves contributions from the vestibular system and the visual and somatosensory systems, platform posturography was developed to assess equilibrium as a whole.

The most commonly used system is the EquiTest. The patient stands on a platform, is secured in a harness, and faces a visual surround. Under the direction of the computer, the platform and visual surround can move independently or together in response to patient sway. Force plates in the platform monitor the patient's sway and center of gravity. The computer records the information for analysis and uses the information to move the surround during parts of the test.

The test protocol comprises 2 parts, namely, the motor-control test and the sensory-organization test. In the motor-control test, the platform administers sudden anteroposterior and posteroanterior translations while the force plates record the patient's response to the perturbations. Three movements (small, medium, and large) are used to cause specified rotations around the ankle joint, shifting the center of gravity.

In a different motor-control test, small toes-up and toes-down platform rotations are presented. During both movements, the force plates record the distribution of weight over the feet during the movement, and the latency of the patient response to platform movement is calculated. Conditions that disturb spinal reflexes increase response latency during the motor control test. Adaptation to repeated movements is also calculated.

In the sensory-organization test, the platform and visual surround are manipulated to test the patient's relative reliance on VOR, visual, and proprioceptive/somatosensory systems. During the first 3 test conditions, the platform remains fixed. In the first test condition, the subject stands quietly with eyes open while the platform and visual surround remain stationary. In the second test condition, the patient stands with eyes closed. In the third condition, the visual surround moves in response to information from the force plate, ie, when the patient leans forward, the visual surround falls away from the patient proportionally (sway referencing). The effect of this condition is to remove reliable visual cues, forcing the use of the vestibular system and, more importantly, the somatosensory system.

In test conditions 4, 5, and 6, the platform moves to follow the forward-backward sway of the patient. Platform movement removes reliable somatosensory cues for equilibrium. In condition 4, the visual surround remains fixed while the subject's eyes are open. In condition 5, the patient's eyes are closed. In condition 6, both the platform and visual surround are sway referenced, providing inaccurate visual and somatosensory information and forcing the reliance on vestibular inputs.

The clinical usefulness of platform posturography continues to be debated. In general, the consensus is that the test is not diagnostic for specific disease entities. The actual usefulness of the test is in the functional evaluation of equilibrium in the following situations:

Responses are documented in subjects with suspected malingering or psychiatric disorders. The ability of platform posturography to detect malingerers by their specific patterns of response is well established.

A program of vestibular rehabilitation is planned, and response to treatment is monitored in patients who have a variety of equilibrium problems. Patients who may be at particular risk of falling and sustaining possible injury can be monitored.

Patients who have disequilibrium because of elevated cerebrospinal fluid pressure can be monitored.

Electrocochleography

Although electrocochleography is not extremely sensitive, it is highly specific for conditions related to inner ear fluid imbalance (most commonly Ménière disease).

Auditory brainstem response

Testing of the auditory brainstem response (ABR) can help in the diagnosis of rare cases of microvascular compression of cranial nerve VIII in the cerebellopontine angle or root-entry zone.

Vestibular evoked myogenic potentials

A test of the patient's vestibular evoked myogenic potentials (VEMPs) can help determine the neural integrity of the saccule and inferior vestibular nerve. The saccule, which has some sound sensitivity, is innervated by means of the inferior vestibular nerve. The inferior vestibular nerve has its main input to the lateral vestibular nucleus (Deiter nucleus), where the 2 main postural tracts originate. The medial vestibulospinal tract is responsible for postural control of the neck, whereas the lateral vestibulospinal tract is dedicated to the lower trunk and limbs. For the most part, sound-evoked VEMPs are considered completely unilateral.

The test is performed simply by placing EMG electrodes on the anterior neck muscles including the sternocleidomastoid muscle. The patient holds their head up unsupported, using only their anterior neck muscles. The patient is instructed to tense the muscle during acoustic stimulation, and relax after the stimulation stops. Loud clicks or tone bursts (95-100 DB nHL) are repetitively presented to each ear. If the neck muscles are not activated, no VEMP is produced.

This technology is currently still evolving, and its clinical utility is still being determined. The technology is currently being applied to patients with suspected Ménière disease when the diagnosis is unclear. More recently, it has been applied to patients with superior canal dehiscence and vestibular schwannomas.

Pathology and Treatment

Benign paroxysmal positional vertigo

The most common cause of true vertigo is Benign Paroxysmal Positional Vertigo (BPPV). The classic history of an individual presenting with BPPV consists of symptoms of acute vertigo lasting less than 1 minute that occurs when the patient lies supine, sits up, rolls over in bed, or tilts his or her head backward. After the patient assumes one of these positions, vertigo and torsional nystagmus usually begin within 1-4 seconds. This latency period also applies to a reversal of nystagmus when the patient returns to the upright position.

BPPV is often related to head trauma; however, it is frequently is found in older patients without a clear history of head trauma. Particles (probably dislodged otoconia) that become trapped in the posterior semicircular canal cause BPPV. Although the posterior semicircular canal is the most common site of the lesion, in rare cases patients have horizontal or superior canal variants.

Although the condition may spontaneously resolve in many patients, others seek medical care for this unsettling problem. Medications, such as meclizine or benzodiazepines, are usually not helpful in the treatment of BPPV. The most effective treatment is repositioning of the canalith, which is an office-based maneuver in which the particles are shifted out of the semicircular canal and into the vestibule, where they do not cause symptoms.

Vestibular neuritis

Intense vertigo that often begins acutely after an upper respiratory or flulike illness characterizes vestibular neuritis. Hearing is usually not affected. Severe vertigo lasts 24-48 hours and gradually subsides.

After the vertigo resolves, patients may experience unsteadiness for weeks as the vestibular system gradually accommodates. Treatment is usually symptomatic after one ensures that the patient does not have a central etiology of symptoms, such as Wallenberg syndrome. Drugs such as meclizine, promethazine, or prochlorperazine are useful in suppressing vertigo and nausea and vomiting, which can be distressing.

Ménière disease

Ménière disease (or syndrome) typically manifests as a combination of 4 symptoms, namely, hearing that fluctuates in 1 ear (though Ménière disease can be bilateral), tinnitus that fluctuates in 1 ear, aural fullness, and episodes of vertigo that last for hours. However, Ménière disease often presents with just 1 or 2 symptoms of

the tetrad that occur months to years before involving the entire tetrad. Low-frequency hearing loss is a typical manifestation in Ménière disease.

A relative overproduction or underabsorption of endolymph is thought to cause Ménière disease. The underlying etiology is unknown. Evaluate patients with suspected Ménière disease for syphilis, because patients who have late tertiary syphilis can present with identical symptoms. A fluorescein treponema antibody (FTA) test can be used for this purpose.

Ménière disease initially is treated with sodium restriction and possibly diuresis. Vestibular suppressants are useful during episodes. A combination of a diuretic and a vestibular suppressant controls episodes of vertigo in 60-80% of patients. Patients whose symptoms fail to respond to conservative treatment and who continue to have episodes of vertigo may benefit from a variety of treatments.

Transtympanic gentamicin can be used to perform a chemical labyrinthectomy to exploit the ototoxicity of this aminoglycoside.1

Endolymphatic sac decompression (ESD) can be performed. This outpatient procedure is the most commonly performed surgery for Ménière disease. Through the mastoid, the endolymphatic sac is exposed and freed of surrounding bone. Some surgeons insert a shunt to drain endolymph from the sac, though the benefit of this maneuver compared with simple decompression of the sac is not clear. With ESD, the rate of substantial control of symptoms is approximately 80% while it spares the patient's hearing.

Sectioning of the vestibular nerve. This procedure is performed through a posterior or middle fossa craniotomy. The vestibular division of cranial nerve VIII is cut, sparing the auditory division. The benefit of the operation is preservation of hearing in all but a few patients, with a >90% success rate in terminating episodes of vertigo.

Labyrinthectomy can be performed in patients with unilateral symptoms who have poor hearing that cannot be improved by a hearing aid. This procedure remains the criterion standard in the treatment of unilateral Ménière disease and the highest success rate in terminating episodes of vertigo. However, all of the remaining hearing in the treated ear is lost.

Superior canal dehiscence

Superior canal dehiscence syndrome is an entity in which the superior semicircular canal has become dehiscent in the floor of the middle fossa. Patients tend to report that loud sounds or pressure changes exacerbate their vertiginous symptoms. The diagnosis is typically made with a high-resolution computed tomography scan. Surgical treatment currently involves a middle fossa craniectomy with diagnosis and patching of the dehiscent canal.2

Central causes

Exclude central causes in patients with vertigo. Etiologies such as multiple sclerosis (see Image 1), Wallenberg lateral medullary syndrome, cerebellar ischemia or infarction (see Image 2), benign or malignant CNS or posterior fossa neoplasms (see Image 3), or Arnold-Chiari malformation (see Image 4) may cause patients to present with vertigo and signs of vestibular disturbance. In almost every case, careful neurologic examination and examination of the peripheral vestibular system reveal either CNS abnormalities or other cranial nerve abnormalities.