What is the differential diagnosis and systematic approach for a patient presenting with dizziness, distinguishing vertigo from light‑headedness?

Differential Diagnosis of Dizziness

The most critical first step is to classify dizziness by timing and triggers—not by the patient's vague description of "spinning" versus "lightheadedness"—because this temporal pattern directly predicts the underlying pathology and guides physical examination. 1, 2, 3

Classification Framework: Four Vestibular Syndromes

The American Academy of Otolaryngology-Head and Neck Surgery recommends categorizing every dizzy patient into one of four syndromes based on duration and triggers 1, 2:

1. Triggered Episodic Vestibular Syndrome (seconds to <1 minute)

• Benign Paroxysmal Positional Vertigo (BPPV) accounts for 42% of all vertigo cases and is triggered exclusively by specific head position changes 1, 2
• Diagnosis requires a positive Dix-Hallpike maneuver showing 5-20 second latency, torsional upbeating nystagmus toward the affected ear, and symptom resolution within 60 seconds 1, 2, 3
• No imaging is indicated for typical BPPV with positive Dix-Hallpike and no red flags 1, 3

2. Spontaneous Episodic Vestibular Syndrome (minutes to hours)

• Vestibular migraine causes 14% of all vertigo cases but is severely under-recognized, particularly in young patients 1, 2
• Diagnostic criteria require episodic vestibular symptoms lasting 5 minutes to 72 hours, migraine by International Headache Society criteria, and at least two migraine features (headache, photophobia, phonophobia) during at least two vertiginous episodes 1
• Ménière's disease presents with fluctuating low-to-mid frequency sensorineural hearing loss, aural fullness, and tinnitus—the fluctuating hearing loss distinguishes it from vestibular migraine 1, 2
• At least two documented spontaneous vertigo episodes over months to years are required for definitive Ménière's diagnosis 1

3. Acute Vestibular Syndrome (days to weeks of continuous symptoms)

• Vestibular neuritis accounts for 41% of peripheral vertigo cases, presenting as a single prolonged episode of severe rotational vertigo lasting 12-36 hours followed by 4-5 days of decreasing disequilibrium, without hearing loss, tinnitus, or aural fullness 1, 2
• Posterior circulation stroke represents 25% of acute vestibular syndrome cases overall, but rises to 75% in high vascular risk cohorts (age >50 with hypertension, diabetes, atrial fibrillation, or prior stroke) 1, 2
• Critical pitfall: 75-80% of patients with posterior circulation stroke have no focal neurologic deficits on standard examination 1, 2

4. Chronic Vestibular Syndrome (weeks to months)

• Medication side effects are the leading reversible cause—review antihypertensives, sedatives, anticonvulsants, and psychotropic drugs 4, 1
• Anxiety/panic disorder can produce both lightheadedness (from hyperventilation) and true vestibular dysfunction 4, 1
• Posttraumatic vertigo persists chronically after head trauma with vertigo, disequilibrium, tinnitus, and headache 4, 1

Critical Distinguishing Features

Vertigo vs. Lightheadedness

• Vertigo reflects true vestibular pathology (peripheral ear/vestibular apparatus or central brainstem/cerebellar lesions) and is often accompanied by nausea, vomiting, and intolerance to head motion 1, 5
• Lightheadedness indicates non-vestibular etiologies: cardiovascular disorders (orthostatic hypotension, arrhythmias), medication side effects, or psychiatric conditions 1, 5
• Trigger distinction: Standing up from supine suggests postural hypotension (cardiovascular), whereas head position changes relative to gravity suggest BPPV (vestibular) 4, 1

Peripheral vs. Central Vertigo

Peripheral causes (ear/vestibular apparatus):

• BPPV: seconds, positional triggers 1, 2
• Vestibular neuritis: days, no hearing loss 1, 2
• Ménière's disease: minutes to hours, fluctuating hearing loss 1, 2
• Labyrinthitis: sudden severe vertigo >24 hours with profound, non-fluctuating hearing loss 1

Central causes (brainstem/cerebellum):

• Posterior circulation stroke: 25% of acute vestibular syndrome, 75% in high-risk patients 1, 2
• Vertebrobasilar insufficiency: attacks <30 minutes, no hearing loss, gaze-evoked nystagmus that does not fatigue 4, 1
• Vestibular migraine: minutes to hours, migraine features, no fluctuating hearing loss 1, 2

Essential Physical Examination Maneuvers

Dix-Hallpike Maneuver

• Gold standard for BPPV diagnosis 1, 2, 3
• Positive test: 5-20 second latency, torsional upbeating nystagmus toward affected ear, symptoms resolve within 60 seconds 1, 2
• If negative, perform supine roll test for horizontal canal BPPV 1

HINTS Examination (Head-Impulse, Nystagmus, Test of Skew)

• When performed by trained neuro-otology specialists, HINTS achieves 100% sensitivity for detecting stroke, outperforming early MRI (46% sensitivity) 1, 2
• Critical limitation: Emergency physicians or non-specialists do not achieve comparable accuracy—do not rely on HINTS alone in the emergency department 1
• Components suggesting central vertigo: normal head impulse test, direction-changing or vertical nystagmus, present skew deviation 1

Red Flags Requiring Urgent MRI Brain Without Contrast

Obtain immediate MRI for any of the following 1, 2, 3:

• Focal neurological deficits on examination
• Sudden unilateral hearing loss
• Inability to stand or walk
• Downbeating nystagmus or other central nystagmus patterns
• New severe headache accompanying dizziness
• Progressive neurologic symptoms
• HINTS examination suggesting central cause (when performed by trained examiner)
• High vascular risk patients (age >50, hypertension, diabetes, atrial fibrillation, prior stroke) with acute vestibular syndrome, even with normal neurologic examination, because 11-25% harbor posterior circulation stroke 1, 3

Imaging Guidelines

When Imaging Is NOT Indicated

• Typical BPPV with positive Dix-Hallpike test and no red flags 1, 3
• Acute persistent vertigo with normal neurologic exam and peripheral-consistent HINTS pattern (performed by expert) in low vascular risk patients 1
• Nonspecific dizziness without vertigo, ataxia, or neurologic deficits 1

MRI vs. CT Diagnostic Yield

• MRI brain without contrast is first-line for suspected stroke: 4% diagnostic yield vs. <1% for CT 1, 3
• CT head has only 10-20% sensitivity for posterior fossa strokes and misses the majority of posterior circulation infarcts 1, 3
• CT should not be used instead of MRI when stroke is suspected 1, 3

MRI Head and Internal Auditory Canal WITH and WITHOUT Contrast

• Indicated for chronic recurrent vertigo with unilateral hearing loss or tinnitus to exclude vestibular schwannoma 1, 3
• Indicated for suspected Ménière's disease requiring definitive diagnosis 1

Treatment Based on Diagnosis

BPPV

• Canalith repositioning procedures (Epley maneuver) are first-line treatment with 80% success after 1-3 treatments and 90-98% success with repeat maneuvers 1, 2, 3
• No imaging or medication is needed for typical cases 1
• Reassess within one month; counsel about 10-18% recurrence risk at one year and fall prevention 3

Vestibular Neuritis

• Vestibular suppressants (antiemetics, benzodiazepines) limited to acute phase only 1
• Early vestibular rehabilitation to promote central compensation 1

Ménière's Disease

• Salt restriction and diuretics for persistent symptoms 1, 6
• Intratympanic gentamicin for refractory vertigo 1
• Endolymphatic sac decompression surgery for non-responders 1

Vestibular Migraine

• Migraine prophylaxis and lifestyle modifications 1, 3
• Motion intolerance and light sensitivities help differentiate from Ménière's 3

Medication-Induced Dizziness

• Review and reduce/discontinue antihypertensives, sedatives, anticonvulsants, psychotropic drugs 4, 1

Common Diagnostic Pitfalls to Avoid

1. Relying on patient descriptions of "spinning" vs. "lightheadedness" instead of focusing on timing, triggers, and duration 1, 2, 3

2. Assuming normal neurologic exam excludes stroke—75-80% of posterior circulation strokes have no focal deficits 1, 2

3. Ordering routine imaging for isolated dizziness—CT has <1% yield and MRI only 4% yield in the absence of red flags 1, 3

4. Using CT instead of MRI when stroke is suspected—CT misses most posterior circulation infarcts 1, 3

5. Missing vestibular migraine, which is extremely common (14% of all vertigo) but under-recognized, particularly in young patients 1, 2

6. Failing to distinguish fluctuating hearing loss (Ménière's) from stable/absent hearing loss (vestibular migraine) 1

7. Overlooking medication side effects as a common and reversible cause of chronic dizziness 4, 1