Chapter 194

Dizziness and Vertigo

Nancy McQueen Le, Katie McCabe

Dizziness

Definition and Epidemiology

It is estimated that dizziness affects 20% to 30% of people in the general population.¹ Dizziness is a common, nonspecific term used to describe a variety of subjective states with varied causes. Clinically, it is helpful to classify dizziness into the categories of vertigo, presyncope or syncope, and disequilibrium. Differentiation of the type of dizziness experienced will dictate the direction of evaluation and treatment.

Vertigo is the illusion of movement of either oneself or the environment—spinning, tilting, or moving back and forth. Vertigo can be related to a peripheral or central disorder. Peripheral causes may include benign paroxysmal positional vertigo (BPPV), vestibular neuronitis, acute labyrinthitis, Meniere disease, ototoxicity, and head trauma. Central disorders include brainstem or cerebellar ischemia or hemorrhage, tumors, multiple sclerosis, and a migrainous syndrome.

Presyncopal lightheadedness is often referred to as a sense of wooziness or impending faint. However, lightheadedness is not exclusive to a presyncopal episode and can be a feeling that manifests in some states of disequilibrium or vertiginous conditions. Cardiac conditions associated with lightheadedness or syncope include arrhythmias, sick sinus syndrome, mitral valve prolapse, aortic stenosis, and heart block. Dehydration, hypotension, and cough or Valsalva-related syncope are common causes of vascular-related syncope or presyncope.

Disequilibrium is a sense of insecurity or imbalance, and/or unsteadiness in walking. Although this feeling is described as dizziness, it often occurs in the absence of abnormal head sensations. Disequilibrium may result from Parkinson disease, peripheral neuropathy, vision disorders, musculoskeletal disorders, or cerebrovascular insults.

The lifetime prevalence estimates of significant dizziness range from 17% to 30%, and for vertigo, 3% to 10%.² It has been noted that less than half of patients complaining of dizziness actually have vertigo. Even after evaluation, the largest diagnostic group is represented by dizziness of uncertain cause.

Pathophysiology

Vertigo is caused by an imbalance in the vestibular system that may result from lesions in the inner ear, vestibular nerve, brainstem, or cerebellum. Less commonly, vertigo may result from lesions in the subjective sensory pathways of the thalamus or cortex or stretch receptors in the neck.³

Lightheadedness or presyncope or syncope is most commonly a result of a cardiovascular problem. Causes include orthostatic hypotension, vasovagal episodes, hyperventilation, and decreased cardiac output. Less common causes of lightheadedness are hypoglycemia and seizure activity. It is rarely a manifestation of impending stroke.

Disequilibrium may result from visual impairment, bilateral or unilateral vestibular loss, proprioceptive loss, impaired cerebellar function, or involvement of motor (frontal and basal ganglia) centers. Multisensory disequilibrium describes a syndrome of impaired balance caused by some degree of combined dysfunction in the areas of vestibular, visual, and proprioceptive sensation.³

Clinical Presentation

Dizziness is an intensely subjective sensation that may be difficult to describe. However, a thorough history will often differentiate the type of dizziness being experienced. It is helpful to start by eliciting a description of the dizziness in the patient’s own words, making note of how precise or vague the details are. This description can be further guided through specific questioning and the suggestion of some varied descriptors, especially if the individual is having difficulty articulating his or her sensory experience. Further history is then directed toward defining the characteristics of the dizziness, the time course of individual episodes, the pattern of recurrences, the precipitating and relieving factors, and any associated symptoms. A general medical history must be included, with special focus on neurologic and cardiovascular systems, medication history, and functional history.³^,⁴

True vertigo is such a striking phenomenon that it is usually readily and precisely described as a clear sensation of spinning, tilting, rotating, or swaying. Lack of spinning sensation cannot be used to exclude vestibular disease.⁵ Associated symptoms can include nausea, vomiting, diaphoresis, disequilibrium, nystagmus, and blurry vision. Ear symptoms, including pain or pressure, tinnitus, and altered hearing, may be present.

Lightheadedness is classically described as a sense of wooziness or impending faint. It is often accompanied by diaphoresis, apprehension, nausea, and, in the extreme, an actual transient “blackout” with diminished vision but with persisting vague awareness of one’s surroundings. In these patients, it is important to ask about heart palpitations, chest discomfort, and dyspnea.

Disequilibrium is described as a sense of imbalance or insecurity on rising or when walking. Patients often say they are dizzy when they are not in fact vertiginous or presyncopal but rather “off-kilter.” They may have begun to use a cane or “furniture walking” for unclear reasons. The sense of imbalance may be worse in the dark or may be accompanied by changes in gait characterized by a shortened step length and widened base of support.⁴^,⁶ When the description elicited is vague or ill defined, it may reflect multifactorial issues. A specific sensory experience in multisensory disequilibrium may be difficult to describe.

Dizziness can also be related to psychogenic causes, such as anxiety states or agoraphobia. Nonspecific dizziness can be caused by hyperventilation; however, if associated with nystagmus, a vestibular cause cannot be excluded. Anxiety and apprehension often accompany physiologic dizziness, so complaints of “dizziness” should not be automatically attributed to a psychogenic cause.

Physical Examination

The physical examination in any complaint of dizziness should always include a general medical review as well as a review of medications, including herbals and over-the-counter drugs. This information will guide a more focused examination.

The neurologic examination should include a cognitive screen. Cranial nerves are assessed with particular emphasis on visual acuity, eye movements, and nystagmus. Motor examination should include evaluation of power, muscle tone, coordination, and deep tendon reflexes. Sensory examination emphasizes basic vision and hearing assessments as well as testing of primary sensory modalities. Gait and balance evaluation includes observation of stride, arm swing, tandem gait with eyes opened and then closed, and Romberg sign. Otologic evaluation includes otoscopic examination and hearing assessment including the Weber and Rinne tests.

Cardiovascular evaluation includes cardiac rate and rhythm, auscultation of heart sounds and carotid bruits, and blood pressure measurement. Orthostatic vital signs, both blood pressure and heart rate, should also be determined.

A neuro-otologic examination refers to a number of special examination procedures considered when problems related to vertigo or disequilibrium are suspected, which may be performed in a specialty clinic setting. These procedures specifically assess the vestibulo-ocular and vestibulospinal systems and help distinguish between peripheral disorders and central disorders. They may include evaluation for nystagmus, position testing (Hallpike-Dix maneuver; Box 194-1), head-fixed/body-turn maneuvers, postural sway on a foam surface, and stepping test (marching in place with the eyes closed).⁴

Box 194-1

Positional Nystagmus Testing (Hallpike-Dix Maneuver)

1. Check the patient for spontaneous nystagmus while he or she is seated on the examining table.

2. Bring the patient quickly back to the recumbent or supine position with the head extended back 30 to 45 degrees over the end of the bed or table and the head tilted 30 to 45 degrees to one side (i.e., one ear down toward the floor).

3. Repeat the previous step two times, once with the head tilted to the left, and then again with the head tilted to the right.

4. Observe the patient for latency, duration, direction, and fatigability of nystagmus, both while positioned down and as helped to upright position.

Diagnostics

If a vestibular lesion is suspected, the Hallpike-Dix positioning maneuver would be performed (see Box 194-1). Further examination might be pursued in consultation with an ear, nose, and throat (ENT) or neurology specialist, including vestibular laboratory testing, an audiogram, or neuroimaging. Vestibular laboratory testing can help differentiate peripheral from central lesions, confirm lateralization of a documented abnormality, and allow serial evaluation for monitoring purposes.²^,⁴ Furthermore, it can give valuable functional information and help guide physical therapy interventions. Vestibular laboratory studies include electronystagmography, rotational testing, and posturography.

Audiology evaluation, including the Weber and Rinne tests, may have an important adjunctive role in helping establish or confirm a suspected diagnosis. Many disorders resulting in vertigo have associated hearing involvement. The presence or absence of specific hearing findings can help confirm or exclude some conditions, and differentiate a central versus a peripheral cause. Hearing loss is defined as conductive or sensorineural on the basis of the cause.

Neuroimaging may be considered when central (brain) or structural (bony labyrinthine, internal auditory canal) lesions are amenable to visualization. Either a computed tomography (CT) scan or magnetic resonance imaging (MRI) is appropriate, depending on what is suspected. Magnetic resonance angiography is used when vertebrobasilar insufficiency is a concern.

If cardiac issues are suspected, evaluation routinely begins with electrocardiography (ECG). Holter monitoring or telemetry may also be indicated if an arrhythmia is suspected. Serial orthostatic vital signs in conjunction with these studies can provide important data. Echocardiography may be indicated to further evaluate cardiac status.

When multisystem disequilibrium is suspected or must be excluded, formal ophthalmologic evaluation is necessary. Assessment of peripheral nerve function by electromyography and nerve conduction velocity in these instances can be definitive.

Electroencephalography may be considered to exclude seizure activity (see Chapter 201). Vertigo, disequilibrium, and lightheadedness are not common manifestations of seizures, and thus such testing is commonly under the guidance of a neurologist.

The choice of laboratory diagnostic studies should be guided by presentation and examination. A basic laboratory review usually includes thyroid-stimulating hormone (TSH) concentration, complete blood count (CBC), electrolyte values, serum glucose concentration, blood urea nitrogen (BUN) concentration, creatinine concentration, vitamin B₁₂ level, and rapid plasma reagin (RPR), as indicated.