Differential Diagnosis for Persistent Dizziness
Classification Framework
The most critical first step is to classify persistent dizziness by timing and triggers, not by the patient's subjective description of symptoms. 1, 2, 3 This approach directly guides your physical examination and distinguishes benign peripheral causes from dangerous central pathology like stroke.
Four Vestibular Syndromes
Persistent dizziness falls into the Chronic Vestibular Syndrome category when symptoms last weeks to months or longer. 1, 2 The differential diagnosis includes:
Most Common Causes of Chronic Vestibular Syndrome:
- Anxiety or panic disorder - Often presents with vague, non-specific dizziness without clear triggers 1, 2
- Medication side effects - Leading reversible cause; review antihypertensives, sedatives, anticonvulsants, and psychotropic drugs 1, 2
- Posttraumatic vertigo - History of head trauma with persistent symptoms including vertigo, disequilibrium, tinnitus, and headache 1, 2
- Posterior fossa mass lesions - Progressive symptoms with neurologic deficits 1, 2
- Cervicogenic vertigo - Variable presentation related to neck pathology 1
Other Chronic Presentations to Consider:
- Persistent Postural-Perceptual Dizziness (PPPD) - Chronic non-vertiginous dizziness exacerbated by upright posture and visual stimuli 2
- Vestibular migraine - May present chronically with headache, photophobia, and phonophobia 2, 3
- Ménière's disease - Episodic attacks with fluctuating hearing loss, aural fullness, and tinnitus that can become chronic 1, 4
- Bilateral vestibular hypofunction - Progressive imbalance, oscillopsia with head movement 2
Critical History Elements
Focus on these specific details rather than vague descriptions:
- Duration of individual episodes: Seconds suggest BPPV (unlikely if truly persistent), minutes to hours suggest vestibular migraine or Ménière's, days to weeks suggest vestibular neuritis, persistent suggests chronic syndrome 2, 3
- Triggers: Head position changes (BPPV), pressure changes (superior canal dehiscence), none (vestibular neuritis, central causes) 2, 3
- Associated symptoms:
- Medication review - Essential as this is one of the most common and reversible causes 2
- Trauma history - Posttraumatic vertigo can persist chronically 2
Physical Examination
Perform a complete neurologic examination including:
- Cranial nerve testing - Focal deficits suggest central pathology 3
- Cerebellar testing - Ataxia, dysmetria suggest posterior fossa lesion 3
- Gait assessment - Severe postural instability is a red flag for central causes 5
- Nystagmus evaluation - Downbeating or other central patterns require urgent evaluation 2
- Orthostatic vital signs - Rule out orthostatic hypotension as a contributing factor 6, 7
- Dix-Hallpike maneuver - Even if symptoms seem persistent, rule out underlying BPPV 2, 6
Red Flags Requiring Urgent Evaluation
These findings mandate immediate imaging and neurologic consultation:
- Focal neurological deficits 2, 3
- 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
Critical pitfall: 75-80% of patients with posterior circulation stroke causing acute vestibular syndrome have NO focal neurologic deficits initially, so a normal neurologic exam does not exclude stroke. 2, 5
Imaging Strategy
No imaging is routinely indicated for chronic dizziness unless red flags are present. 2 When imaging is necessary:
- MRI brain without contrast is preferred over CT for posterior circulation pathology and has significantly higher diagnostic yield (4% in isolated dizziness vs <1% for CT) 2, 3
- CT head has very low yield (<1% diagnostic yield) and misses posterior fossa strokes; should not be used instead of MRI when stroke is suspected 2, 3, 5
- MRI is indicated for: Progressive symptoms suggesting mass lesion, unilateral/pulsatile tinnitus, asymmetric hearing loss, high vascular risk patients 2, 3
Diagnostic Testing
- Audiologic examination - Obtain for unilateral tinnitus, persistent symptoms, or associated hearing difficulties 2
- Vestibular function testing - Not routinely needed but may be appropriate for atypical presentations or equivocal findings 2, 6
- Laboratory testing - Generally not required; diagnosis is fundamentally clinical based on timing, triggers, and examination 5, 8
- Orthostatic vital sign measurement - Should be performed for patients with simple orthostatic dizziness to diagnose orthostatic intolerance 6
Management Approach
Treatment depends on the identified etiology:
- Medication-induced: Review and adjust medications - most common reversible cause 2
- Anxiety/panic disorder: Psychiatric treatment, cognitive behavioral therapy 1, 2
- Vestibular migraine: Migraine prophylaxis and lifestyle modifications 2, 3
- Ménière's disease: Salt restriction, diuretics; intratympanic dexamethasone or gentamicin for refractory cases 3, 4
- Vestibular rehabilitation therapy: Primary intervention for persistent dizziness that has failed initial treatment; significantly improves gait stability and is particularly beneficial for elderly patients or those with heightened fall risk 2
Avoid pharmacologic intervention with vestibular suppressants (like meclizine) for chronic dizziness, as these medications impair central nervous system compensation and prolong recovery. 7
Common Pitfalls to Avoid
- Relying on patient's description of "spinning" vs "lightheadedness" instead of focusing on timing and triggers 2, 5
- Assuming normal neurologic exam excludes stroke - up to 75-80% of posterior circulation strokes lack focal deficits initially 2, 5
- Routine imaging for isolated dizziness - has low yield and most findings are incidental 2
- Using CT instead of MRI when stroke is suspected - CT misses many posterior circulation infarcts 2, 3
- Failing to perform medication review - one of the most common and reversible causes 2
- Not screening for psychiatric symptoms - anxiety and panic disorder are common causes of chronic dizziness 2