Differential Diagnosis of Dizziness
The differential diagnosis of dizziness is best organized by timing and triggers rather than symptom quality, as this approach more reliably distinguishes benign peripheral causes from dangerous central etiologies. 1
Diagnostic Framework: Four Vestibular Syndromes
The 2017 AAO-HNS guidelines emphasize that focusing on timing (acute vs episodic vs chronic) and triggers (position-change vs spontaneous) is more clinically useful than asking patients to describe their dizziness as "vertigo," "lightheadedness," or "disequilibrium" 1, 2. This creates four distinct categories:
1. Triggered Episodic Vestibular Syndrome (Brief, <1 minute, position-triggered)
- Benign Paroxysmal Positional Vertigo (BPPV) - most common
- Postural hypotension
- Perilymph fistula (pressure-triggered, not position)
- Superior canal dehiscence syndrome (pressure/sound-triggered)
- Central paroxysmal positional vertigo
2. Spontaneous Episodic Vestibular Syndrome (Minutes to hours, no trigger)
- Vestibular migraine - lifetime prevalence 3.2%, accounts for 14% of vertigo cases 1
- Ménière's disease (vertigo + fluctuating hearing loss + tinnitus + aural fullness)
- Posterior circulation TIA
- Medication side effects
- Anxiety/panic disorder
3. Acute Vestibular Syndrome (Days to weeks, persistent)
- Vestibular neuritis - most common peripheral cause
- Labyrinthitis (includes hearing loss)
- Posterior circulation stroke (25% prevalence in AVS patients) 3
- Demyelinating diseases
- Posttraumatic vertigo
4. Chronic Vestibular Syndrome (Weeks to months)
- Anxiety/panic disorder
- Medication side effects
- Posttraumatic vertigo
- Posterior fossa mass lesions
- Cervicogenic vertigo
Complete Differential by Category
Otologic Disorders 1
- Ménière's disease
- Vestibular neuritis (41% of vertigo in primary care) 1
- Labyrinthitis
- Superior canal dehiscence syndrome
- Posttraumatic vertigo
- Perilymphatic fistula
Neurologic Disorders 1
- Vestibular migraine
- Posterior circulation stroke/TIA (10% of cerebellar strokes present with isolated vertigo) 1
- Demyelinating diseases (MS)
- Central nervous system lesions
- Vertebrobasilar insufficiency
- Inner ear lesions
Other Entities 1, 4, 1
- Anxiety or panic disorder
- Cervicogenic vertigo
- Medication side effects (antihypertensives, anticonvulsants, cardiovascular drugs)
- Postural hypotension
- Toxic, infectious, and metabolic conditions
Initial Work-Up Algorithm
Step 1: History - Timing and Triggers
- Duration: Seconds? Minutes? Hours? Days?
- Trigger: Position change? Spontaneous? Pressure/sound?
- Associated symptoms: Hearing loss, tinnitus, aural fullness, headache, photophobia, neurologic deficits
- Risk factors: Hypertension, diabetes, heart disease (predict central causes) 5
Step 2: Physical Examination
For Triggered Episodic (suspected BPPV):
- Dix-Hallpike maneuver - diagnoses posterior canal BPPV (torsional upbeating nystagmus) 6
- Supine roll test - if Dix-Hallpike shows horizontal or no nystagmus, assesses lateral canal BPPV 6
For Acute Vestibular Syndrome:
- HINTS examination (Head Impulse, Nystagmus, Test of Skew) - when performed by trained practitioners, 100% sensitive for stroke vs 46% for early MRI 3, 7
- Red flags for central cause 1, 4:
- Downbeating nystagmus on Dix-Hallpike (without torsional component)
- Direction-changing nystagmus without head position change
- Gaze-evoked nystagmus
- Baseline nystagmus without provocation
- Inability to suppress nystagmus with visual fixation
- Any focal neurologic signs
For All Patients:
- Orthostatic blood pressure
- Complete neurologic examination
- Cardiovascular examination
- Assessment for nystagmus characteristics 7, 8
Step 3: Testing - When NOT to Order
Do NOT obtain imaging or vestibular testing if: 6
- Patient meets diagnostic criteria for BPPV with typical Dix-Hallpike findings
- No additional signs/symptoms inconsistent with BPPV
- Normal neurologic examination
DO obtain MRI brain (without and with contrast preferred) if: 3
- Acute vestibular syndrome with abnormal HINTS examination
- Any central neurologic signs
- Failure to respond to appropriate peripheral treatment
- Risk factors for stroke with acute persistent vertigo (11% have infarct even without focal deficits) 3
Step 4: Laboratory Testing
Generally not helpful or required 7, 8. Consider only if history suggests:
- Metabolic causes (glucose, thyroid function)
- Medication toxicity (drug levels)
- Infectious causes (based on clinical context)
Critical Pitfalls to Avoid
Don't rely on symptom quality alone - patients cannot reliably distinguish "vertigo" from "lightheadedness," but can identify timing and triggers 2, 7
Don't miss posterior circulation stroke - 75-80% of AVS from infarct have NO focal neurologic deficits 3. Use HINTS examination in all acute vestibular syndrome patients.
Don't assume peripheral = benign in high-risk patients - hypertension, diabetes, and heart disease significantly increase risk of central causes 5
Don't forget concurrent diagnoses - BPPV can coexist with Ménière's disease, vestibular neuritis, or occur after trauma 4
Gaze nystagmus is the single most significant predictor of central origin on multivariate analysis 5
Failure to respond to appropriate treatment (canalith repositioning for BPPV, vestibular rehabilitation) should raise concern for misdiagnosis 1, 4