Differential Diagnosis of Dizziness
Diagnostic Framework: Timing and Triggers Over Patient Descriptions
The most critical step in evaluating dizziness is to categorize the presentation by timing and triggers rather than relying on patient descriptions of "spinning" versus "lightheadedness," which are unreliable. 1, 2, 3
The American Academy of Otolaryngology-Head and Neck Surgery defines four distinct vestibular syndromes that organize the differential diagnosis 1:
1. Acute Vestibular Syndrome (continuous dizziness lasting days to weeks)
- Vestibular neuritis - most common peripheral cause 1
- Labyrinthitis - distinguished by associated hearing loss 1
- Posterior circulation stroke - CRITICAL to exclude; 75-80% have NO focal neurologic deficits on standard exam 1, 3
- Demyelinating diseases 1
- Posttraumatic vertigo 1
2. Triggered Episodic Vestibular Syndrome (brief episodes <1 minute triggered by head position)
- Benign paroxysmal positional vertigo (BPPV) - most common cause of peripheral vertigo overall, accounting for 42% of vertigo cases in primary care 1
- Postural hypotension - triggered by position change from supine to upright 1
- Perilymphatic fistula - triggered by pressure changes (Valsalva), may have fluctuating hearing loss 1
- Superior canal dehiscence syndrome - triggered by pressure, not position; diagnosed by CT temporal bones 1
- Vertebrobasilar insufficiency - triggered by neck rotation 1
- Central paroxysmal positional vertigo - rare but dangerous mimic of BPPV 1
3. Spontaneous Episodic Vestibular Syndrome (episodes lasting minutes to hours, not triggered)
- Vestibular migraine - ≥5 episodes of moderate-to-severe vestibular symptoms lasting 5 minutes to 72 hours, with migraine features in ≥50% of episodes 1, 2
- Ménière's disease - episodic vertigo lasting 20 minutes to 12 hours with fluctuating hearing loss, tinnitus, and aural fullness 1, 2
- Posterior circulation transient ischemic attack - HIGH RISK for subsequent stroke 1
- Medication side effects 1
- Anxiety or panic disorder 1
4. Chronic Vestibular Syndrome (persistent dizziness lasting weeks to months)
- Anxiety or panic disorder - most common in this category 1
- Medication side effects - review all medications, especially antihypertensives and CNS depressants 1
- Posttraumatic vertigo - may require repeated treatments; bilateral in rare cases 1
- Posterior fossa mass lesions 1
- Cervicogenic vertigo - triggered by neck rotation relative to body while upright 1
Critical Red Flags Requiring Immediate Neuroimaging
Any of the following mandate urgent evaluation for posterior circulation stroke or other life-threatening pathology 1, 2, 3:
- Focal neurological deficits - diplopia, dysarthria, facial numbness, limb weakness, sensory changes 1, 2, 3
- Inability to stand or walk independently 3
- New severe headache with dizziness 3
- Sudden unilateral hearing loss with vertigo 3
- Downbeating nystagmus or other central nystagmus patterns 3
- Abnormal HINTS examination (normal head impulse test, direction-changing nystagmus, or skew deviation) in acute vestibular syndrome - 100% sensitivity for stroke 1, 3
- Loss of consciousness - never from peripheral vestibular disorders 3
Otologic Differentials
BPPV is characterized by brief positional vertigo WITHOUT hearing loss, diagnosed by Dix-Hallpike maneuver showing transient upbeating-torsional nystagmus 1.
Ménière's disease presents with the classic triad of episodic vertigo (20 minutes to 12 hours), fluctuating hearing loss, and aural fullness/tinnitus in the affected ear 1, 2.
Superior canal dehiscence differs from BPPV by pressure-induced (not position-induced) vertigo, often with conductive hearing loss on audiometry 1.
Vestibular neuritis causes acute continuous vertigo lasting days without hearing loss, while labyrinthitis includes hearing loss 1.
Posttraumatic vertigo is significantly more refractory, requiring repeated treatments in up to 67% of cases versus 14% for non-traumatic BPPV 1.
Neurologic Differentials
Posterior circulation stroke is the most critical diagnosis to exclude in acute vestibular syndrome, as standard neurologic examination is normal in 75-80% of cases 1, 3. MRI with diffusion-weighted imaging is required; CT head has only 20-40% sensitivity 3.
Vestibular migraine is diagnosed when ≥5 episodes of vestibular symptoms (5 minutes to 72 hours) occur with migraine features in ≥50% of episodes 1, 2.
Vertebrobasilar insufficiency produces nystagmus that does not fatigue and is not suppressed by gaze fixation, distinguishing it from BPPV 1.
Demyelinating diseases and CNS lesions present with acute or chronic vestibular syndromes and require MRI for diagnosis 1.
Non-Vestibular Differentials
Nearly half of emergency department visits for dizziness have non-vestibular, non-neurologic medical diagnoses 1.
Postural hypotension is provoked by moving from supine to upright position, distinct from BPPV's positional triggers 1.
Anxiety and panic disorders may present with vague lightheadedness, though high prevalence of actual vestibular dysfunction exists in these patients 1.
Medication side effects from antihypertensives, cardiovascular medications, anticonvulsants (carbamazepine, phenytoin), and CNS depressants must be reviewed 1.
Cervicogenic vertigo is triggered by head rotation relative to the body while upright, not by position changes relative to gravity 1.
Treatment Approaches by Diagnosis
BPPV Treatment
Canalith repositioning maneuvers (Epley maneuver) are first-line treatment for posterior canal BPPV 1, 4, 5. Vestibular rehabilitation exercises are effective adjuncts 5, 6.
Vestibular Neuritis Treatment
Corticosteroids are recommended for vestibular neuritis 4. Vestibular rehabilitation accelerates central compensation 5.
Ménière's Disease Treatment
Intratympanic dexamethasone or gentamicin for refractory cases 4. Dietary sodium restriction and diuretics for initial management.
Symptomatic Treatment
Meclizine 25-100 mg daily in divided doses is FDA-approved for vertigo associated with vestibular system diseases 7. However, prolonged use should be avoided as it impairs central compensation 5.
Common Diagnostic Pitfalls
Do not rely on patient descriptions of dizziness type - focus exclusively on timing and triggers 1, 2, 3.
Do not assume normal neurologic exam excludes stroke in acute vestibular syndrome - 75-80% of posterior circulation infarcts have no focal deficits 1, 3.
Do not order CT head for stroke evaluation in dizziness - MRI with diffusion-weighted imaging is required 3.
Do not order routine imaging for isolated dizziness with typical peripheral features - diagnostic yield is extremely low 3.
Do not miss bedside testing opportunities - Dix-Hallpike maneuver and HINTS examination provide more diagnostic value than imaging in most cases 3.
Consider concurrent diagnoses - BPPV can occur with Ménière's disease, vestibular neuritis, or after head trauma 1.