Introduction

Dizziness is a common and often challenging clinical complaint. It encompasses several distinct sensations, including vertigo, lightheadedness, presyncope, and disequilibrium. A structured evaluation begins with careful history-taking, followed by a targeted physical examination, and, when necessary, selected diagnostic testing. The presence of nystagmus is a key clinical sign that can help localize the underlying disorder.

Defining the Terms

Precise terminology is essential. Vertigo is the false sensation of movement, usually rotational, and indicates a vestibular system dysfunction, either peripheral or central. Dizziness is a broader term that may describe unsteadiness, lightheadedness, or a floating feeling. Nystagmus is an involuntary, rhythmic oscillation of the eyes; its direction, waveform, and behavior with fixation provide important diagnostic clues.

Historical Assessment

The first step is to clarify what the patient means by dizziness. Ask the patient to describe the sensation in their own words, then classify it as vertigo, lightheadedness, disequilibrium, or another sensation. Distinguish acute attacks from chronic symptoms. Establish the timing and triggers of symptoms. Vertigo lasting seconds and provoked by head movement suggests benign paroxysmal positional vertigo. Episodes lasting minutes to hours with unilateral tinnitus and hearing loss suggest Meniere disease. Continuous vertigo lasting days may indicate vestibular neuritis or a central process such as stroke.

Important historical points include associated symptoms such as hearing loss, tinnitus, aural fullness, headache, focal neurologic deficits, palpitations, and syncope. Review the medication list for ototoxic or hypotensive drugs. Ask about recent head trauma, infection, or immobilization. Also clarify the patient's age and cardiovascular risk profile, since central vertigo due to vertebrobasilar ischemia is a diagnosis not to be missed.

Physical Examination

The physical examination should include vital signs, orthostatic blood pressure measurements, a cardiovascular examination, and a complete neurologic examination. The vestibular and ocular motor examination is central to the evaluation and includes testing of visual acuity, eye movements, smooth pursuit, saccades, and the vestibulo-ocular reflex.

Nystagmus Examination

Observe for nystagmus with the patient looking straight ahead, and then with gaze to the left and right. Note the direction of the fast phase, whether the nystagmus is horizontal, vertical, or torsional, and whether it increases or decreases with fixation. Peripheral nystagmus from a unilateral vestibular lesion is usually horizontal-torsional, beats away from the involved ear, and is suppressed by visual fixation. Central nystagmus may be vertical, direction-changing with gaze, bilateral, or resistant to fixation. Upbeat or downbeat nystagmus, or pure torsional nystagmus, strongly suggests a central disorder.

Positional Testing

The Dix-Hallpike maneuver is used to diagnose posterior canal benign paroxysmal positional vertigo. The patient is moved rapidly from a seated position to a head-hanging position with the head rotated to one side. Reproduction of vertigo with geotropic torsional nystagmus confirms the diagnosis. The supine roll test evaluates horizontal canal involvement. Always be cautious when performing these maneuvers in patients with cervical spine disease or vascular risk factors.

HINTS Examination

In patients with acute, continuous vertigo, the HINTS examination is a valuable bedside tool to distinguish central from peripheral causes. HINTS stands for Head Impulse test, Nystagmus, and Test of Skew. A normal head impulse test, direction-changing nystagmus, or skew deviation suggests a central cause and mandates urgent neuroimaging. Conversely, an abnormal head impulse, direction-fixed nystagmus, and no skew deviation point to a peripheral vestibular disorder.

Additional Diagnostic Testing

Most patients with dizziness can be diagnosed on the basis of history and physical examination alone. When the diagnosis remains uncertain, further testing may include audiometry for suspected cochlear involvement, video nystagmography to quantitate nystagmus and caloric responses, and vestibular evoked myogenic potentials. Magnetic resonance imaging of the brain and internal auditory canals is indicated when a central lesion, mass, or demyelination is suspected. In acute presentations with vascular risk factors, computed tomography may be performed rapidly, although it has limited sensitivity for posterior fossa ischemia and infarction.

Red Flags

Certain findings require urgent attention. These include sudden severe vertigo with new headache, focal neurologic deficits, gait ataxia, dysarthria, diplopia, or weakness. Also concerning are vertical nystagmus, gaze-evoked nystagmus in multiple directions, or a normal head impulse test in a patient with continuous vertigo. Such findings raise concern for stroke or other central nervous system pathology and should prompt immediate neuroimaging and specialist referral.

Conclusion

The evaluation of the dizzy patient relies on careful classification of the symptom, a thorough history, and a targeted examination emphasizing nystagmus and the vestibulo-ocular reflex. Recognizing peripheral patterns of vertigo can lead to effective treatment such as canalith repositioning maneuvers, while identifying central patterns may be life-saving. A systematic approach allows the clinician to distinguish benign causes from dangerous ones and to choose appropriate investigations and referrals.