Making the diagnosis
Differential diagnosis
The trick is less “PPPD or something else?” than “PPPD andwhat else?” — it frequently rides alongside the very disorders it can be confused with.
Mimics and co-morbidities
Other conditions also cause dizziness. Migraine-related dizziness comes in attacks. BPPV is brief and triggered by specific head positions. Some people feel faint only on standing because of a blood-pressure drop. PPPD is different: it is constant and made worse by movement and busy visual places — and the balance tests are normal.
Key separators: vestibular migraine is episodic with migraine features; BPPV is brief and positional with a positive Dix-Hallpike; bilateral vestibulopathy shows an objective deficit on testing; orthostatic dizziness tracks a documented blood-pressure fall on standing. PPPD is persistent, worse with the three exacerbators, with normal tests.1
Crucially, PPPD co-exists with these conditions as often as it mimics them — particularly vestibular migraine, and as a sequel to neuritis or BPPV.2 Diagnosing PPPD does not exclude an active disorder, and treating only one when both are present explains many “treatment-resistant” cases.3 Anxiety is a comorbidity to address, not the diagnosis.
PPPD against its mimics
PPPD is the reference row; tap a mimic to surface the discriminator.
Tap a mimic to reveal the discriminator. Persistent symptoms with the three exacerbators and normal tests is the key.
When to reconsider — and when to treat both
Discrete attacks with migraine features point to vestibular migraine (and may co-exist); brief positional vertigo to BPPV; imbalance worse in the dark with reduced testing to bilateral vestibulopathy; light-headedness on standing to an orthostatic cause (Understanding vertigo symptoms). Where a mimic is also present, treat both.
Key points
- Vestibular migraine is episodic; BPPV is brief/positional; bilateral vestibulopathy has an objective deficit; orthostatic dizziness tracks a BP fall.
- PPPD is persistent, provoked by the three exacerbators, with normal tests.
- PPPD frequently co-exists with these disorders — diagnosing it does not exclude active disease.
- Treating only one of two coexisting disorders explains many apparently treatment-resistant cases.