Differential Diagnosis of Vertigo
Initial Classification Framework
Classify vertigo by timing and triggers into four distinct vestibular syndromes rather than relying on vague descriptive terms—this approach narrows diagnostic possibilities and guides evaluation efficiently. 1, 2
The Four Vestibular Syndromes
Triggered Episodic Vestibular Syndrome:
- Brief episodes lasting <1 minute provoked by specific head/body position changes 1, 3
- BPPV is the most common cause, accounting for 42% of vertigo cases in general practice 1, 2
- Central paroxysmal positional vertigo (rare central mimic that fails repositioning maneuvers) 1
- Perilymphatic fistula (following trauma or barotrauma) 1
- Superior canal dehiscence syndrome (triggered by loud sounds or Valsalva) 1
Spontaneous Episodic Vestibular Syndrome:
- Episodes lasting minutes to hours without positional triggers 2, 3
- Ménière's disease: episodic vertigo (20 minutes to hours) with fluctuating hearing loss, tinnitus, and aural fullness; accounts for 10% of cases 1, 2
- Vestibular migraine: vertigo attacks lasting hours with migraine history; accounts for 3.2% of cases 1, 3
- Vertebrobasilar insufficiency/TIA: episodes typically <30 minutes without hearing loss, may precede stroke by weeks to months 1, 2
Acute Vestibular Syndrome:
- Continuous vertigo lasting days to weeks with nausea, vomiting, and intolerance to head motion 2, 3
- Vestibular neuritis: acute severe vertigo lasting days without hearing loss; accounts for 41% of cases 1, 3
- Labyrinthitis: similar to vestibular neuritis but with associated hearing loss 1, 2
- Posterior circulation stroke: cerebellar or brainstem infarction; 10% of cerebellar strokes present with isolated vertigo, and 75-80% of posterior circulation strokes initially lack focal neurologic deficits 1, 3
Chronic Vestibular Syndrome:
- Dizziness lasting weeks to months 2
- Anxiety disorders, medication side effects, posterior fossa masses 2
Critical Peripheral vs. Central Differentiation
Nystagmus Characteristics
Peripheral vertigo nystagmus:
- Horizontal with rotatory (torsional) component 1, 2
- Unidirectional 1, 3
- Suppressed by visual fixation 1, 2
- Fatigable with repeated testing 1, 2
- Brief latency period (5-20 seconds) before onset 1, 3
Central vertigo nystagmus:
- Pure vertical (upbeating or downbeating) without torsional component 1, 2
- Direction-changing without changes in head position 1, 2
- Direction-switching with gaze 2
- Not suppressed by visual fixation 1, 2
- Baseline nystagmus present without provocative maneuvers 2
Physical Examination Red Flags for Central Pathology
Severe postural instability (inability to stand or walk) strongly suggests central pathology, particularly vertebrobasilar insufficiency or cerebellar lesions 1, 2
Additional neurological symptoms:
- Dysarthria, dysmetria, dysphagia 2
- Sensory or motor deficits 2
- Diplopia or Horner's syndrome 2
- Limb weakness or hemiparesis 2
- Truncal/gait ataxia 2
Essential Diagnostic Maneuvers
Dix-Hallpike Maneuver
Technique: Bring patient from upright to supine position with head turned 45 degrees to one side and neck extended 20 degrees 3
Positive test for BPPV (peripheral):
- Vertigo and nystagmus with 5-20 second latency period 1, 3
- Torsional and upbeating nystagmus 2
- Crescendo-decrescendo pattern 2
- Fatigable with repetition 1, 3
- Resolution within 60 seconds 2
Concerning findings suggesting central pathology:
- Immediate onset without latency 2
- Persistent nystagmus that doesn't fatigue 2
- Purely vertical nystagmus without torsional component 1, 2
- Downbeating nystagmus without torsional component 2
HINTS Examination
The HINTS examination (Head Impulse test, Nystagmus type, Test of Skew) has 92.9% sensitivity and 83.4% specificity for central causes when performed by trained clinicians 1
When to Suspect Misdiagnosis and Order Neuroimaging
Immediate neuroimaging is warranted for:
- Severe postural instability with falling 2
- New-onset severe headache with vertigo 2
- Any additional neurological symptoms 2
- Downbeating nystagmus on Dix-Hallpike without torsional component 2
- Apogeotropic horizontal nystagmus on supine roll test 2
- Isolated positional downbeat nystagmus 2
- Failure to respond to 2-3 particle repositioning maneuvers 1, 2
- Gaze-evoked nystagmus (typical of central lesions) 2
- Nystagmus that doesn't fatigue and isn't suppressed by gaze fixation 2
Critical context: CNS disorders masquerading as BPPV are found in 3% of treatment failures, with acute brain lesions detected in 6% on CT and 11% on MRI in patients with central paroxysmal positional vertigo 1
Important: Approximately 25% of patients presenting with acute vestibular syndrome have cerebrovascular disease, rising to 75% in high vascular risk cohorts 2
Common Pitfalls to Avoid
- Missing cerebellar stroke: 10% of cerebellar strokes present similarly to peripheral vestibular disorders—always assess for neurological signs 3
- Overlooking medication effects: Aminoglycosides and other ototoxic drugs can cause vestibular toxicity 2, 3
- Misinterpreting nystagmus: Pure vertical nystagmus without torsion is central until proven otherwise 3
- Ignoring treatment failure: Lack of response to repositioning maneuvers after 2-3 attempts mandates evaluation for central pathology 1, 3
- Overlooking subtle neurological signs that may indicate central pathology 2
- Assuming loss of consciousness is vertigo: Loss of consciousness never occurs with true vertigo and suggests a different diagnosis 3
Symptomatic Treatment Considerations
Meclizine is FDA-approved for treatment of vertigo associated with vestibular system diseases in adults, with recommended dosage of 25-100 mg daily in divided doses 4. However, it causes drowsiness and has anticholinergic effects, requiring caution in patients with asthma, glaucoma, or prostate enlargement 4. Peripheral vertigo often responds to canalith repositioning procedures or vestibular rehabilitation, while central vertigo typically does not respond to these interventions 2.