In a 32-year-old with chronic positional dizziness and weakness, H-shaped nystagmus on Dix-Hallpike, slight Romberg positivity, no spontaneous nystagmus while seated, and occasional eye‑muscle twitching, what is the most likely diagnosis and first‑line treatment?

Likely Diagnosis: Benign Paroxysmal Positional Vertigo (BPPV) with Possible Incomplete Central Compensation

The most likely diagnosis is BPPV of the posterior semicircular canal, given the chronic positional dizziness worsening with head movements, though the atypical nystagmus pattern ("H-shaped" rather than classic torsional upbeating) and persistent symptoms over years raise concern for either atypical BPPV, incomplete central compensation, or a coexisting central pathology that requires urgent evaluation. 1

Critical Diagnostic Concerns

Red-Flag Assessment Required Immediately

Your patient exhibits several concerning features that deviate from typical BPPV:

• "H-shaped" nystagmus pattern during neurological examination is not the classic torsional upbeating nystagmus expected in posterior canal BPPV 1, 2
• Patient-reported "eye twitching" after Dix-Hallpike without visible nystagmus suggests either subclinical BPPV or a central process 2
• Years of symptoms rather than the typical episodic course of BPPV 1
• Positive Romberg test indicates proprioceptive or central vestibular dysfunction beyond simple BPPV 1

These atypical features mandate urgent MRI of the brain without contrast to exclude posterior circulation stroke, cerebellar lesion, or vestibular schwannoma before proceeding with BPPV treatment. 1, 3

Why Imaging Is Essential in This Case

• Pure vertical or atypical nystagmus patterns (your "H-shaped" finding) are red flags for central pathology 1
• Direction-changing nystagmus without positional changes suggests central vertigo 1
• Chronic symptoms lasting years with incomplete compensation may indicate an underlying structural lesion 4, 5
• The diagnostic yield of MRI is 4% in atypical presentations versus <1% for typical BPPV 3

Diagnostic Algorithm

Step 1: Repeat Dix-Hallpike Maneuver Bilaterally (Today)

Perform the test correctly to confirm or refute BPPV: 2

• Turn head 45° to the right, rapidly move patient from sitting to supine with head extended 20° below horizontal 2
• Look for: torsional upbeating nystagmus with 5-20 second latency, crescendo-decrescendo pattern, resolution within 60 seconds 1, 2
• Repeat on the left side 2

If positive (classic findings): Proceed to Epley maneuver immediately 6, 1

If negative or atypical nystagmus: Perform supine roll test for lateral canal BPPV (10-15% of cases) 1, 2

Step 2: Perform Supine Roll Test

• With patient supine, rapidly turn head 90° to each side 1
• Look for horizontal nystagmus 1

Step 3: Order MRI Brain Without Contrast (Urgent)

Obtain imaging if any of the following are present: 1, 3

• Atypical nystagmus pattern (your "H-shaped" finding qualifies)
• Nystagmus that does not fatigue with repeated testing
• Baseline nystagmus without provocative maneuvers
• Positive Romberg test suggesting central pathology
• Failure to meet all three classic Dix-Hallpike criteria (latency, torsional upbeating nystagmus, resolution <60 seconds) 2

Your patient meets multiple criteria for urgent imaging.

First-Line Treatment (After Imaging Clears Central Pathology)

If BPPV Is Confirmed

Perform the Epley (canalith repositioning) maneuver immediately—this is the only evidence-based first-line treatment for BPPV: 6, 1

• Success rate: 80% after 1-3 treatments 1, 3
• If initial treatment fails, repeat maneuvers achieve 90-98% success 1, 3
• Do NOT prescribe vestibular suppressants (meclizine, diazepam, antihistamines)—they interfere with central compensation and have no role in BPPV treatment 6

Reassessment Protocol

• Re-examine within 1 month to confirm symptom resolution 6
• Repeat Dix-Hallpike if symptoms persist 6, 1
• If symptoms persist after 2-3 repositioning attempts, refer for vestibular rehabilitation therapy 3, 7

Alternative Diagnoses to Consider

Vestibular Migraine (14% of All Vertigo Cases)

• Extremely common but under-recognized, especially in young adults 1, 3
• Episodes last minutes to hours (not seconds like BPPV) 1
• Associated with photophobia, phonophobia, or visual aura during at least 50% of episodes 1
• Key distinguishing feature: stable or absent hearing loss (versus fluctuating loss in Ménière's) 1

Incomplete Central Compensation

• Years of symptoms suggest failure of central vestibular compensation 4, 5
• Contributing factors to assess: 4
  • Visual problems (cataracts, refractive errors)
  • Peripheral neuropathy (diabetes, alcohol)
  • Medications causing dizziness (antihypertensives, sedatives, anticonvulsants) 1, 4
  • Psychological factors (anxiety, fear of falling) 4, 8

Vertebrobasilar Insufficiency

• Episodes typically last <30 minutes without hearing loss 1
• Gaze-evoked nystagmus that does not fatigue 1
• May precede stroke by weeks to months 1
• Requires vascular imaging (MRA or CTA) if suspected 1

Critical Pitfalls to Avoid

• Do not assume BPPV without performing proper Dix-Hallpike testing bilaterally—50% of BPPV patients describe atypical symptoms like "lightheadedness" rather than classic vertigo 1, 2
• Do not prescribe vestibular suppressants for BPPV—they prevent central compensation and have no evidence of efficacy 6
• Do not skip imaging when nystagmus is atypical—10% of cerebellar strokes present similarly to peripheral vestibular disorders 1
• Do not rely on a single negative Dix-Hallpike—negative predictive value is only 52% in primary care 2
• Do not overlook medication side effects—antihypertensives, sedatives, and anticonvulsants are leading reversible causes of chronic dizziness 1, 4

Modifying Factors Requiring Special Attention

Age-Related Considerations (32 Years Old)

• Vestibular migraine is extremely common in this age group 1
• Lower vascular risk than older adults, but vertebrobasilar insufficiency can still occur from arterial dissection 1

Risk Factors for Residual Dizziness After BPPV Treatment

• Moderate to severe baseline dizziness (odds ratio 2.017) 8
• Moderate to severe anxiety (odds ratio 2.228) 8
• Screen for anxiety using GAD-7 and address proactively 8

Fall Risk Assessment

• Positive Romberg test indicates increased fall risk 1
• Counsel on home safety and activity restrictions until resolved 1
• Consider vestibular rehabilitation if symptoms persist 3, 7