Evaluation of Dizziness
Initial Diagnostic Framework
Categorize dizziness by timing and triggers rather than symptom quality ("spinning" vs "lightheadedness"), as this approach directly identifies benign peripheral vestibular disorders versus dangerous central causes like stroke. 1, 2
The modern evidence-based approach classifies patients into three vestibular syndromes based on temporal patterns 1, 2:
1. Acute Vestibular Syndrome (AVS)
- Presentation: Continuous severe vertigo lasting days to weeks with constant symptoms 1, 2
- Key examination: Perform HINTS (Head Impulse, Nystagmus, Test of Skew) examination 1, 2
- Critical evidence: HINTS has 100% sensitivity for posterior circulation stroke when performed by trained practitioners, vastly superior to early MRI (46% sensitivity) 1, 2
- Differential: Vestibular neuritis vs. posterior circulation stroke 1, 3
2. Triggered Episodic Vestibular Syndrome
- Presentation: Brief episodes lasting seconds to <1 minute triggered by specific head movements 1, 2
- Key examination: Perform Dix-Hallpike maneuver and supine roll test 1, 2
- Diagnostic criteria for BPPV: Latency period of 5-20 seconds, torsional upbeating nystagmus toward affected ear, symptoms that increase then resolve within 60 seconds 2, 3
- Differential: BPPV (most common), superior canal dehiscence, perilymphatic fistula 2, 3
3. Spontaneous Episodic Vestibular Syndrome
- Presentation: Episodes lasting minutes to hours without positional triggers 1, 2
- Associated symptoms guide diagnosis: Hearing loss/tinnitus/aural fullness → Ménière's disease; headache/photophobia/phonophobia → vestibular migraine 1, 2
- Differential: Vestibular migraine, Ménière's disease, vertebrobasilar insufficiency 2, 3
Essential History Components
Duration is the most diagnostically valuable feature 1, 2:
- Seconds (<1 minute): BPPV 1, 2
- Minutes to hours: Vestibular migraine or Ménière's disease 1, 2
- Days to weeks: Vestibular neuritis or stroke 1, 2
- Head position changes → BPPV 1, 2
- Pressure changes → Superior canal dehiscence 1, 2
- No triggers → Vestibular neuritis or stroke 1, 2
- Hearing loss, tinnitus, aural fullness → Ménière's disease 1, 2
- Headache, photophobia, phonophobia → Vestibular migraine 1, 2
Physical Examination
Complete neurologic examination is essential 1:
Vestibular-specific maneuvers 1, 2:
- Dix-Hallpike maneuver for posterior canal BPPV 1, 2
- Supine roll test for lateral canal BPPV (10-15% of BPPV cases) 2, 3
- HINTS examination for acute vestibular syndrome 1, 2
Imaging Decisions
No imaging indicated for 1, 2:
- Brief episodic vertigo with typical BPPV features and positive Dix-Hallpike 1, 2
- Acute persistent vertigo with normal neurologic exam and HINTS consistent with peripheral vertigo by trained examiner 1, 2
MRI brain without contrast indicated for 1, 2:
- Abnormal neurologic examination 1, 2
- HINTS examination suggesting central cause 1, 2
- High vascular risk patients with acute vestibular syndrome 1, 2
- Unilateral or pulsatile tinnitus 1, 2
- Asymmetric hearing loss 1, 2
CT head has very low yield (<1% diagnostic yield for isolated dizziness) and should not be used instead of MRI when stroke is suspected 1, 2
Critical Red Flags Requiring Urgent Evaluation
- Focal neurological deficits 2
- Sudden hearing loss 2
- Inability to stand or walk 2
- Downbeating nystagmus or other central nystagmus patterns 2
- New severe headache 2
- Failure to respond to appropriate vestibular treatments 2
Common Pitfalls to Avoid
Do not rely on patient's description of "spinning" vs "lightheadedness" - focus on timing and triggers instead 1, 2
Do not assume normal neurologic exam excludes stroke - 75-80% of patients with acute vestibular syndrome from posterior circulation infarct have no focal neurologic deficits 1, 2
Do not use CT when stroke is suspected - CT misses many posterior circulation infarcts 1, 2
Do not perform HINTS examination if not properly trained - results are less reliable when performed by non-experts 2