bppv-differential-diagnosis

name

bppv-differential-diagnosis

description

Distinguishes BPPV from its key mimics at the bedside — postural hypotension, vestibular paroxysmia, vestibular migraine, central positional vertigo, and chronic unilateral vestibular hypofunction — using history, trigger patterns, nystagmus characteristics, and response to treatment. Use when a patient has positional vertigo and you're unsure if it's BPPV, when Dix-Hallpike is atypical, or when the patient has not responded to repositioning maneuvers. Trigger phrases: "is this BPPV or something else", "BPPV not responding to Epley", "atypical positional vertigo", "mimics of BPPV", "positional dizziness differential".

BPPV Differential Diagnosis Checker

Use this skill when:

• Positional vertigo is present but Dix-Hallpike is atypical or negative
• Patient has not responded to repositioning maneuvers after 2–3 attempts
• Clinical features don't quite fit classic posterior canal BPPV

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Step 1 — Confirm the Core BPPV Pattern First

Classic posterior canal BPPV has ALL of the following:

Feature	Expected in BPPV
Trigger	Specific head movements — lying down, rolling in bed, looking up, bending forward
Duration of each episode	< 1 minute (usually 30–60 seconds)
Dix-Hallpike response	Latency 2–20s, upbeat-torsional nystagmus, duration <1 min, fatigues with repetition, severe vertigo
Hearing	Normal — no hearing loss, no tinnitus
Neurologic exam	Normal
Between attacks	Mild imbalance possible; NO sustained dizziness

If ANY of the above is atypical → work through the mimics below.

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Step 2 — Mimic 1: Postural (Orthostatic) Hypotension

Key distinguishing features:

	BPPV	Postural Hypotension
Sensation	Vertigo (spinning/tilting)	Near-faint, lightheadedness, "nearly blacking out"
Triggered by lying down / rolling in bed	✅ Yes	❌ No
Triggered by standing up	❌ Rarely	✅ Yes — the key trigger
Dix-Hallpike nystagmus	Present	Absent

Confirm: Measure BP and pulse lying → standing. Drop ≥20 mmHg systolic = orthostatic hypotension.

⚠️ Both can cause dizziness on arising from bed — but postural hypotension is triggered by the act of standing, not by the head position itself.

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Step 3 — Mimic 2: Chronic Unilateral Vestibular Hypofunction

Key distinguishing features:

	BPPV	Unilateral Vestibular Hypofunction
Episode duration	30–60 seconds	Very brief — 1 to 2 seconds only
Trigger	Any positional change (lying, rolling, looking up/down)	Rapid head turns only
Looking up / bending forward triggers it	✅ Yes	❌ No
Dix-Hallpike	Positive (typical pattern)	Usually negative

The fleeting 1–2 second duration with rapid head turns is the giveaway for vestibular hypofunction.

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Step 4 — Mimic 3: Vestibular Paroxysmia

Key distinguishing features:

	BPPV	Vestibular Paroxysmia
Episode duration	30–60 seconds	1 to several seconds — very brief
Frequency	Episodic, often weeks between bouts	Multiple times per day
Triggers	Head position changes	Sometimes head turn, sometimes unprovoked
MRI finding	Normal	May show neurovascular compression

Very brief attacks recurring many times daily → think vestibular paroxysmia, not BPPV. MRI of the posterior fossa is warranted.

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Step 5 — Mimic 4: Vestibular Migraine

Key distinguishing features:

	BPPV	Vestibular Migraine
Episode duration	< 1 minute	Minutes to hours (occasionally seconds)
Recurrence pattern	Weeks to months between bouts	More frequent recurrences
Associated symptoms	None during attack	Headache, photophobia, phonophobia (may be subtle)
Age of onset	Any age, more common >60	Often younger patients
Positional nystagmus	Typical BPPV pattern	Atypical — does not fit BPPV criteria
Response to Epley	✅ Usually resolves	❌ Does not resolve

⚠️ Vestibular migraine can mimic BPPV closely, including positional provocation. Clues: younger age, recurrences over hours-to-days (not weeks-to-months), migrainous symptoms (even subtle), atypical nystagmus on Dix-Hallpike.

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Step 6 — Mimic 5: Central Positional Vertigo

Key distinguishing features:

	BPPV	Central Positional Vertigo
Nystagmus on Dix-Hallpike	Upbeat-torsional, latency 2–20s, <1 min, fatigues, severe vertigo	Static, persists as long as position maintained; often downbeat; no latency; nonfatiguing
Effect of visual fixation on nystagmus	Suppressed	Not suppressed
Other neurologic signs	Absent	May be present (ataxia, dysarthria, diplopia)
Cause	Otoconia in posterior canal	Cerebellar lesion (especially vermis); demyelination; Chiari malformation

🚨 Classic central sign: Downbeat positional nystagmus that is static (persists throughout the head-down position, does not fatigue). This needs neuroimaging.

🚨 Patients with static positional nystagmus without prior typical BPPV should be investigated for central disease.

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Summary Decision Table

Feature	BPPV	Postural Hypotension	Vestibular Hypofunction	Vestibular Paroxysmia	Vestibular Migraine	Central Positional Vertigo
Duration	30–60s	Seconds–minutes	1–2s	1–several s	Minutes–hours	Persists in position
Dix-Hallpike	Typical	Negative	Negative	Variable	Atypical	Atypical/static
Hearing loss	No	No	Possible	No	No	Usually no
Neurologic signs	No	No	No	No	No	Possible
Response to Epley	Yes	N/A	N/A	No	No	No

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Clinical Guardrails

• Non-response to Epley after 2–3 sessions = reassess the diagnosis. The most common reasons are wrong canal (horizontal or anterior), wrong side, or a mimic — not treatment failure per se.
• Atypical Dix-Hallpike (no latency, non-fatiguing, persistent, minimal vertigo, or downbeat nystagmus) = central cause until proven otherwise → MRI brain.
• Vestibular migraine is underdiagnosed — ask specifically about headaches, photophobia, or phonophobia during or around dizzy episodes; these may be subtle.
• Subjective BPPV (typical history but no nystagmus on exam) — empiric repositioning is reasonable if history is convincing, but other diagnoses should be considered if treatment fails within a few days.

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Source: Barton JS. "Benign paroxysmal positional vertigo." UpToDate. Last updated Nov 04, 2024.