Dizziness and vertigo are among the most common symptoms causing patients to visit a physician (as common as back pain and headaches). This article outlines the clinical approach to the patient with dizziness from a neurologic perspective. Emphasis is on differentiating peripheral from central dizziness and on the management of the most common diseases. In addition, indications for referral to an otolaryngologist and/or neuro-otologist and for specialized vestibular testing are discussed.
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The overall incidence of dizziness, vertigo, and imbalance is 5-10%, and it reaches 40% in patients older than 40 years. The incidence of falling is 25% in subjects older than 65 years. Falling can be a direct consequence of dizziness in this population, and the risk is compounded in those with other neurologic deficits.
Mild hearing loss is the most common disability in the United States. The incidence of hearing loss is 25% in people younger than 25 years, and it reaches 40% in persons older than 40 years. About 25% of the population report tinnitus. Tinnitus and hearing loss are commonly associated with inner-ear diseases, leading to vertigo and dizziness. About 40% of patients with migraine headaches also have vertigo, motion sickness, and mild hearing loss.
The patient's history is critical in the evaluation of the patient with dizziness. Ask the patient to describe their symptoms by using words other than "dizzy." The rationale for using other words is that patients may use dizzy nonspecifically to describe vertigo, unsteadiness, generalized weakness, syncope, presyncope, or falling. A critical distinction is differentiating vertigo from nonvertigo. Vertigo is the true rotational movement of self or the surroundings. Nonvertigo includes light-headedness, unsteadiness, motion intolerance, imbalance, floating, or a tilting sensation. This dichotomy is helpful because true vertigo is often due to inner-ear disease, whereas symptoms of nonvertigo may be due to central nervous system (CNS), cardiovascular, or systemic diseases.
Sudden onset and vivid memory of vertiginous episodes are often due to inner-ear disease, especially if hearing loss, ear pressure, or tinnitus is also present. Gradual and ill-defined symptoms are most common in CNS, cardiac, and systemic diseases. The time course of vertigo is also important. Episodic true vertigo that lasts for seconds and is associated with head or body position changes is probably due to benign paroxysmal positional vertigo (BPPV). Vertigo that lasts for hours or days is probably caused by Ménière disease or vestibular neuronitis. Vertigo of sudden onset that lasts for minutes can be due to brain or vascular disease, especially if cerebrovascular risk factors are present. These conditions will be discussed in more detail later in this review.
Central vertigo secondary to brainstem or cerebellar ischemia is often associated with other brainstem characteristics, including diplopia, autonomic symptoms, nausea, dysarthria, dysphagia, or focal weakness. Patients with cerebellar disease are frequently unable to ambulate during acute episodes of vertigo. Patients with peripheral vertigo can usually ambulate during episodes and are consciously aware of their environment. A history of headaches, especially migraine headaches, can be associated with migraine-related dizziness. Previous viral illness, cold sores, or sensory changes in the cervical C2-C3 or trigeminal distributions usually indicate vestibular neuronitis or recurrent episodes of Ménière disease.
Dysdiadochokinesis and gait ataxia during episodes are more likely due to cerebellar diseases, especially in the elderly population. Sensory and motor symptoms and signs are usually associated with CNS diseases. The history should include a review of systems (especially head trauma and/or ear diseases) and screening for anxiety and/or depression. History of prescription medicines, over-the-counter medications, herbal medicines, and recreational drugs (including smoking and alcohol) can help to identify pharmacologically induced syndromes.
The most common causes of peripheral vertigo include BPPV, vestibular neuronitis, Ménière disease, and immune-mediated inner-ear disease. The most common cause of central dizziness is migraine, frequently referred to as vestibular migraine or migraine-associated dizziness. Other central causes include demyelination, acoustic tumors, or cerebellar lesions.
In patients with dizziness and vertigo, general examination should emphasize vital signs, supine and standing blood-pressure measurement, and evaluation of the cardiovascular and neurologic systems. Examine the ears for visible external- and/or middle-ear infection and/or inflammation. Test hearing by using a tuning fork or by whispering. Examine the neck for range of motion. However, specific examination of the vestibular system, beyond the ears, nose, throat and neurologic examination, is fundamental to the evaluation of the patient with dizziness.
It is essential to distinguish peripheral versus central vertigo. This is often accomplished by examining for nystagmus. Central nystagmus is a purely horizontal or vertical gaze and not suppressed by visual fixation. Peripheral nystagmus is usually rotatory and most evident with removing visual fixation. A robust oculocephalic reflex and intact visual acuity with active head movements (dynamic visual acuity) reflect good inner ear-vestibular function. Absence of the oculocephalic reflex or a decrease in visual acuity with head movements reflect decreased vestibular function.
The positioning test (Dix-Hallpike test) is an important component of the vestibular examination to identify BPPV commonly caused by otolith debris (canalith) floating in the semicircular canals (canalithiasis) or adhering to the cupula (cupulolithiasis). The Dix-Hallpike maneuver is performed by guiding the patient rapidly from a sitting position with the head turned 45° to 1 side to a lying position. BPPV is due to posterior semicircular canal canalithiasis approximately 90% of the time. Typical nystagmus findings related to benign positioning and its symptoms are delayed by several seconds (latency). They peak in 20-30 seconds and then decay (paroxysmal), with complete resolution of symptoms while the patient maintains the same head position (habituation).
Nystagmus, whether spontaneous, gaze induced, or positional, must be completely characterized to be correctly interpreted. This characterization should include provocative factors, latency, directions, effects of gaze, temporal profiles, habituation, fatigability, suppression by visual fixation, and accompanying sensation of dizziness. Failure to fully characterize nystagmus can easily lead to misdiagnosis.
Other tests to determine the nature of the patient's condition include caloric testing (which precipitates nystagmus), testing of vestibulospinal reflexes (checking gait and postural stability), and the Hamid vestibular stress test. If the results of vestibular examination are normal, hyperventilation for two minutes is helpful in identifying patients with hyperventilation syndrome. This should be done in the sitting position. Hyperventilation must be done while the examiner monitors for nystagmus. Hyperventilation can accentuate both central and peripheral vestibular dysfunction and reproduce dizziness and neurologic symptoms due to hyperventilation syndrome.
Additional tests that are commonly considered include audiometry, vestibular tests, blood tests, CT, and MRI. The yield of MRI in patients younger than 50 years is low (
<1%). The incidence of an acoustic tumor or other brainstem and posterior-fossa lesions also are low. Clinical judgment, careful neurotologic examination, and audio and vestibular studies are often helpful in obviating MRI. The most common vestibular tests are ENG, rotating chair test or sinusoidal harmonic acceleration (SHA), and computerized dynamic posturography (CDP). >
Causes of Peripheral Dizziness/Vertigo and Their Treatment:
1. Vestibular Neuronitis: is a common cause of acute vertigo with an incidence of 170 case per 100,000 people. It is believed to be of viral etiology. A prodromal upper respiratory tract illness may or may not be present. Vertigo without auditory symptoms develops and last for several days. A brief course of an antiemetic and vestibular suppressants is usually needed in the acute phase. Corticosteroids may improve long-term outcomes. Early vestibular rehabilitation is important. Antiviral medications have not proven helpful, possibly because a large spectrum of viruses can cause vestibular neuronitis. One third of patients have chronic vestibular symptoms.
2. Benign Paroxysmal Positional Vertigo (BPPV): is the most common cause of vertigo. The typical symptom is brief vertigo on changing head position. Patients may have a residual sensation of dizziness or disequilibrium between episodes. One half have a symptomatic associated etiology, including vestibular neuronitis, Ménière disease, delayed endolymphatic hydrops, sudden sensorineural hearing-loss syndrome, head trauma, or migraine. The remaining patients are idiopathic. Treatment involves dispersing otolithic debris in the semicircular canals (Brandt-Daroff exercises) or repositioning the particles to the utricle (Epley, Semont, Lempert, and Hamid maneuvers, among others). Medications are not effective in the treatment of BPPV.
3. Meniere DIsease: entails the triad of episodic vertigo, tinnitus, and hearing loss. Untreated, severe hearing loss and unilateral vestibular paresis are inevitable. Bilateral involvement occurs in one third of patients. The mechanism can be hereditary, autoimmune, infectious, or idiopathic. The common pathophysiology is disordered fluid homeostasis in the inner ear, with endolymphatic hydrops representing a histologic footprint rather than an etiology. More than 80% of patients respond to conservative therapy with salt restriction and diuretics. Corticosteroids, given orally or intratympanically, can be used to stabilize active disease. The role of surgical therapy, such as shunting the endolymphatic sac, is controversial. The literature demonstrates wide variation in the effectiveness, or lack thereof, of surgery.
4. Other conditions include Labyrinthitis, Autoimmune inner-ear disease, and non-specific conditions including total cerumen impaction and Cholesteotomas.
Causes of Central Dizziness/Vertigo and Their Treatment:
1. Migraine: is a common disorder, affecting 10% of men and 30% of women. About 25% of migraineurs have dizziness. All forms of dizziness can occur with migraine: vertigo, positional dizziness, disequilibrium, motion intolerance, and visual motion sensitivity. Dizziness can occur as an aura or as part of a headache. However, one third of patients consistently have dizziness in the interval between headaches. The treatment of migraine related dizziness is the same as the treatment of migraine. Headache hygiene and trigger factors should be reviewed. Prophylactic medications are prescribed, if indicated. Abortive medications, such as triptans, are effective for migraine related dizziness, whether accompanied by headache or not.
2. Cerebrovascular Disease: Stroke is the third most common cause of death and the most common cause of disability in adults. The vertebrobasilar circulation supplies the brainstem, cerebellum, and the inner-ear auditory and vestibular structures. Infarction of the cerebellar midline can cause acute vertigo without auditory or other neurologic features (e.g.: isolated vertigo). This potentially life- threatening occurrence must be differentiated from vestibular neuronitis. About one half of patients have other features of bulbar or long tract involvement, which make the diagnosis of stroke clear.
Evaluation of the patient with stroke is directed at identifying correctable vascular risk factors (hypertension, diabetes, hyperlipidemia, smoking) and at determining the mechanism of stroke (small vessel, large vessel, cardioembolic, dissection, hypercoagulability, vasculitis). Secondary prophylactic therapy and rehabilitation are individualized. Both hearing loss and vertigo can occur in the setting of stroke due to either central and/or peripheral injury.
3. Multiple Sclerosis: Multiple sclerosis is a disorder of recurrent, inflammatory CNS demyelination due to an underlying autoimmune disorder. The onset is usually at 20-40 years of age. Episodes begin over hours to a few days and last weeks to months. Typical symptoms include optic neuritis, ocular motor dysfunction, trigeminal neuralgia, sensorimotor deficits, myelopathy, ataxia, and bladder dysfunction. Vertigo, at times mimicking vestibular neuronitis, is a presenting symptom in less than 10% of patients. Dizziness or vertigo occurs at some point in the course in a third of patients. Few patients present with hearing loss due to brainstem involvement.
The diagnosis of multiple sclerosis requires the presence of dissemination in time and space, ie, different neurologic symptoms at different times. Careful history taking, examination, and serial follow-up combined with MRI and spinal-fluid analysis helps in establishing the diagnosis. The diagnosis should not be based on MRI abnormalities alone. Disease-modifying therapy is available, but it is only modestly effective. The search for improved treatment is ongoing.
4. Brain Tumors of the Posterior Fossa: Vestibular schwannoma (acoustic neuroma) is an uncommon lesion with an incidence of 1.1 per 100,000. It typically manifests with slowly progressive, unilateral hearing loss, and tinnitus. Dizziness is not a common symptom, as the vestibular system can compensate for such gradual unilateral hypofunction. Dizziness can occur as the tumor expands in the cerebellopontine angle and effaces the brainstem and cerebellum. Arachnoid cysts can also occur in the posterior fossa and result in subtle and non-specific dizziness and auditory symptoms.
Chiari malformations occurs in a few adults. It is congenital, but often does not become symptomatic until the age of 20-40 years. Occipital headache precipitated by Valsalva maneuvers, coughing, exertion, or changing position is common. Dizziness may occur with the same precipitants. Once suspected, the diagnosis can be confirmed with MRI. Surgery should be considered for patients with more-than-mild symptoms.
5. Head Trauma: Transient vertigo is a common finding after a head injury, even the most mild one. It generally mimics BPPV, and is therefore, positional in nature. Medicine is not effective, but the Epley maneuver will often clear the circulating fluid of the inner ear from the particulate matter which produces the symptoms.
Acute dizziness and vertigo is usually managed with vestibular suppressants, antiviral medication, and antiemetic medications. Steroids can be used in selected patients. Vestibular suppressants should be used for a few days at most because they delay the brain's natural compensatory mechanism for peripheral vertigo.
Antihistamines such as Meclizine (Antivert) prevent the histamine response in sensory nerve endings and blood vessels and are effective in treating most forms of vertigo. Anticholinergics like Scopolamine work centrally by suppressing conduction in the vestibular-cerebellar pathways. Benzodiazepines such as Diazepam (Valium) appear to potentiate effects of gamma-aminobutyric acid (GABA) and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters. These effects may prevent vertigo and emesis. Phenothiazines such as Promethazine (Phenergan) are effective in treating emesis, possibly because of their effects in the dopaminergic mesolimbic system.
One of the biggest pitfalls is the clinician's inclination to associate vertigo or dizziness to BPPV. Making this diagnosis without doing a comprehensive examination to rule out more serious causes of vertigo and dizziness with subject the practitioner to medical-legal risk. Failure to diagnose an underlying condition (e.g.: vertebrobasilar ischemia, brainstem tumor, severe cervical spondylosis) that results in further neurological injury, therefore, is the most common medical- legal hazard in the evaluation of vertigo and dizziness.
Another concern is the failure to recognize the rare case of suppurative labyrinthitis or the unusual case associated with meningitis. This can result in catastrophic complications for the patient. Also, once diagnosed with vertigo and dizziness, the physician should take steps to help prevent associated injuries secondary to falls. Lastly, it is important to prevent complications from medications prescribed (e.g.: an acute dystonic reaction to an antiemetic).
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