Introduction

Dizziness is one of the most common complaints encountered in the emergency department. It affects young and old alike and accounts for a substantial share of emergency visits each year. The complaint is notoriously difficult to evaluate because patients use the word "dizziness" to describe many different sensations, and the underlying cause can range from a benign inner ear condition to a life-threatening stroke or cardiac arrhythmia. A structured, time-conscious approach helps emergency clinicians sort through the possibilities and identify the patients who need urgent intervention.

Classifying the Symptom

The first step in the emergency department is to clarify the precise nature of the symptom. The broad term dizziness is usually divided into four subtypes:

• Vertigo: the false sensation of movement, often described as spinning, tilting, or swaying. It typically points to a disorder of the vestibular system, either peripheral or central.
• Lightheadedness: a feeling of faintness or impending loss of consciousness, often associated with presyncope, dehydration, or cardiovascular causes.
• Disequilibrium: a sense of unsteadiness when standing or walking, often bilateral or nonspecific, and frequently multifactorial in older adults.
• Presyncope: a sensation of almost fainting, often with visual dimming, diaphoresis, or nausea, suggesting reduced cerebral perfusion.

Patients rarely use these terms in a strictly defined manner, so the history should focus on what they actually experienced during the episode, not simply the word they chose to describe it.

Initial Assessment in the Emergency Department

Once the subtype is clarified, the next goal is to answer two questions: is the cause likely peripheral and benign, or is it central, cardiac, or otherwise dangerous? The history and physical examination are the most important tools. Key historical points include the time course, the triggers, and the associated symptoms.

• Onset: Was the dizziness sudden, as in a stroke or vestibular neuritis, or gradual and progressive?
• Duration: Do episodes last seconds, minutes, hours, or days? Is the dizziness continuous or intermittent?
• Triggers: Does the dizziness occur when rolling over in bed, standing up, walking, or moving the head? Is it provoked by coughing or straining?
• Associated symptoms: Is there hearing loss, tinnitus, aural fullness, severe headache, neck pain, double vision, slurred speech, facial weakness, limb weakness, chest pain, palpitations, or breathlessness?
• Past history: Does the patient have risk factors for stroke, heart disease, diabetes, or a known vestibular disorder?

Medication history is also essential, as many drugs can cause dizziness, including antihypertensives, sedatives, anticonvulsants, and aminoglycoside antibiotics.

Red Flags and Dangerous Diagnoses

One of the primary responsibilities of the emergency clinician is to rule out dangerous and treatable causes of dizziness. These include cerebrovascular, cardiac, metabolic, and infectious conditions.

• Posterior circulation stroke or transient ischemic attack involving the cerebellum or brainstem
• Vertebral artery dissection, often presenting with sudden dizziness, neck pain, and focal neurologic signs
• Subarachnoid hemorrhage, classically with a thunderclap headache and dizziness
• Acute coronary syndrome or dysrhythmia, including complete heart block and ventricular tachycardia
• Severe hypoglycemia, hyponatremia, or other metabolic disturbances
• Bacterial meningitis or encephalitis, particularly when fever and neck stiffness are present
• Toxic exposures, including carbon monoxide poisoning, alcohol, or drug overdose

Gait instability is an especially important red flag. A patient who cannot stand or walk steadily in the emergency department, particularly one with vascular risk factors, warrants careful consideration for a central cause.

Bedside Examination

The physical examination should include vital signs, orthostatic blood pressure and heart rate measurements, a cardiovascular examination, and a thorough neurologic examination. Orthostatic vitals help identify volume depletion or autonomic dysfunction. The cardiac examination may reveal an irregular rhythm or a murmur that suggests a structural cause of presyncope.

The neurologic examination should pay particular attention to nystagmus, eye movement abnormalities, and coordination. In a patient with continuous vertigo and nystagmus, the HINTS examination, which evaluates the head impulse test, the direction of nystagmus, and the test of skew, can help distinguish a central cause from a peripheral one. This examination is reliable only when performed by clinicians trained in its use and when the patient has persistent, spontaneous nystagmus. It is not valid for intermittent, positional, or transient dizziness.

For patients whose dizziness is triggered by head position, the Dix-Hallpike test can be performed to diagnose posterior canal benign paroxysmal positional vertigo (BPPV). A positive test reproduces vertigo and characteristic torsional nystagmus. A careful assessment of gait, including the ability to stand with feet together and eyes closed, provides additional information about the risk of falls.

Diagnostic Testing

Imaging and laboratory testing should be chosen selectively. A computed tomography scan of the head is frequently ordered in the emergency department, but it has low sensitivity for acute ischemic stroke in the posterior fossa. If stroke is suspected, magnetic resonance imaging with diffusion-weighted imaging is the preferred study, although it may not be available immediately. In the meantime, the patient should be managed as having a potential cerebrovascular event, including close monitoring and early consultation with a stroke service where available.

An electrocardiogram is appropriate for older adults and those with cardiac symptoms or risk factors, because dysrhythmia is a common cause of unexplained dizziness and presyncope. A rapid blood glucose measurement can quickly identify hypoglycemia. Additional laboratory tests, such as a complete blood count, electrolytes, renal function, and a pregnancy test where relevant, are guided by the clinical presentation. Continuous cardiac monitoring should be considered for patients with unexplained syncope or an abnormal electrocardiogram.

Common Peripheral Vestibular Disorders

Most patients who have vertigo rather than lightheadedness will ultimately be diagnosed with a peripheral vestibular disorder. The most common are described below.

• Benign paroxysmal positional vertigo (BPPV): brief episodes of vertigo triggered by head movement, such as rolling over in bed or looking up. It is caused by displaced calcium carbonate crystals within a semicircular canal and is diagnosed with the Dix-Hallpike test.
• Vestibular neuritis: an acute, often severe episode of continuous vertigo lasting days, accompanied by nausea, vomiting, and gait instability, without hearing loss. It is thought to be due to viral inflammation of the vestibular nerve.
• Labyrinthitis: similar to vestibular neuritis but with the addition of hearing loss, tinnitus, and aural fullness, indicating involvement of the cochlea as well.
• Meniere's disease: recurrent spontaneous episodes of vertigo lasting from minutes to hours, with hearing loss, tinnitus, and a feeling of fullness in the affected ear.

These conditions are distressing but generally not dangerous, and they respond well to symptomatic management and specific repositioning maneuvers where appropriate.

Treatment in the Emergency Department

Treatment begins with symptomatic relief. Patients who are nauseated or vomiting may require intravenous fluids and antiemetic medication. Vestibular suppressants, such as oral or parenteral antihistamines or a short course of a benzodiazepine, can reduce the intensity of vertigo in acute vestibular neuritis and labyrinthitis, but they should be used sparingly and for a limited time because they can impair the central compensation process that normally follows a vestibular injury.

For BPPV, the Epley canalith repositioning maneuver is effective and can be performed at the bedside when the affected ear has been identified by the Dix-Hallpike test. The maneuver can resolve symptoms immediately in many patients, although recurrence is common and the patient should be advised to avoid sudden head movements for a few days.

For vestibular neuritis, some clinicians consider a short course of corticosteroids, but this remains controversial and should be decided in consultation with an appropriate specialist. Antibiotics are not indicated for viral vestibular neuritis. When a bacterial cause is suspected, for example in the setting of otitis media, fever, or ear drainage, urgent specialist referral is needed.

Disposition and Discharge Planning

Admission to the hospital is generally required for patients with suspected stroke or transient ischemic attack, dangerous cardiac arrhythmias, syncope with concerning features, inability to ambulate, persistent vomiting leading to dehydration, or a home environment that is not safe for a dizzy patient. Older adults with multiple medical problems and a high risk of falls may also require observation even when a benign cause is suspected.

Patients who are discharged need clear instructions. For benign positional vertigo and vestibular neuritis, they should be told that recovery can take from days to several weeks and that the brain requires time to adjust. They should avoid driving, operating heavy machinery, and climbing ladders until the dizziness has resolved. They should also be instructed to rise slowly from lying to standing positions and to use support when walking if unsteady.

Every discharged patient should receive return precautions. They should return to the emergency department or seek urgent medical attention if they develop a sudden severe headache, double vision, slurred speech, facial droop, arm or leg weakness, chest pain, palpitations, fainting, or an inability to keep down fluids.

Conclusion

Dizziness in the emergency department is a challenging complaint that demands a systematic approach. By clarifying the subtype of dizziness, searching for red flags, performing a targeted physical examination, and using diagnostic tests selectively, emergency clinicians can identify the relatively small number of patients with serious disease while providing effective relief for the many patients with benign peripheral vertigo. Clear discharge instructions, close follow-up, and careful attention to fall risk complete the emergency department episode of care.