What could be causing a patient's extreme dizziness, feeling unsteady and light-headed, particularly with quick movements, standing up, and walking, which worsens after using ear drops?

Differential Diagnosis: Positional Dizziness Without True Vertigo

This patient's presentation—lightheadedness, unsteadiness, and disequilibrium triggered by position changes and worsening with ear drops—suggests either atypical BPPV, medication-related vestibular toxicity from the ear drops, or orthostatic hypotension, rather than classic BPPV or central pathology. The absence of room-spinning vertigo is a critical distinguishing feature that narrows the differential significantly.

Key Clinical Distinction: Not True Vertigo

The patient explicitly denies room-spinning sensation, which is the hallmark of vestibular disorders. True rotational vertigo is NOT present here—instead, she describes lightheadedness and feeling unsteady, which represents dizziness rather than true vertigo 1, 2. The American Academy of Otolaryngology-Head and Neck Surgery emphasizes that a confident description of spinning is specific for inner ear dysfunction, and the absence of this argues against classic peripheral vestibular pathology 2.

However, this does not completely exclude BPPV, as up to 50% of BPPV patients report lightheadedness, dizziness, or feeling "off balance" rather than true room-spinning vertigo 1. In elderly patients particularly, BPPV can appear as an isolated sense of instability brought on by position changes such as sitting up, looking up, bending over, and reaching 1.

Primary Diagnostic Considerations

1. Atypical BPPV (Most Likely)

Despite the absence of spinning, BPPV remains the leading diagnosis given the positional triggers (quick movements, standing, walking) and brief episodic nature 1:

• In up to one-third of cases with atypical histories of positional vertigo, Dix-Hallpike testing will still reveal positional nystagmus, strongly suggesting posterior canal BPPV 1
• The positional triggers (standing up, quick movements, walking) are classic for BPPV, which is provoked by everyday activities like rolling over in bed, tilting the head upward, or bending forward 1
• Episodes in BPPV typically last less than 1 minute and are triggered by changes in head position relative to gravity 1

2. Ototoxicity from Ear Drops (Critical Red Flag)

The worsening of symptoms after using ear drops is highly concerning for vestibular toxicity 1:

• Certain ototoxic medications can produce dizziness and vertigo as side effects 1
• This temporal relationship (symptoms worsening with ear drop use) suggests either direct vestibular toxicity or exacerbation of underlying vestibular dysfunction
• Immediate discontinuation of the ear drops should be considered pending evaluation

3. Orthostatic Hypotension

Dizziness provoked by standing up specifically suggests postural hypotension 1:

• The American Academy of Otolaryngology-Head and Neck Surgery notes that postural hypotension produces episodic dizziness or vertigo provoked by moving from supine to upright position 1
• This differs from BPPV's provocative positional changes, but can coexist
• Orthostatic vital signs must be obtained

4. Concurrent Vestibular Disorders

BPPV can occur in conjunction with other vestibular disorders such as Meniere's disease and vestibular neuritis 1:

• Clinicians must consider the possibility of more than one vestibular disorder being present 1
• The ear drop exacerbation may unmask an underlying concurrent vestibular pathology

Essential Diagnostic Workup

Immediate Actions:

1. Perform bilateral Dix-Hallpike maneuver to confirm or exclude BPPV 1, 2

   • Even with atypical history, this may reveal characteristic nystagmus with 5-20 second latency and resolution within 60 seconds 1
   • Must be performed bilaterally to determine which ear is involved 1

2. Obtain orthostatic vital signs (blood pressure and heart rate supine, then at 1 and 3 minutes standing) 1

   • A drop of ≥20 mmHg systolic or ≥10 mmHg diastolic confirms orthostatic hypotension

3. Identify and discontinue the ear drops immediately 1

   • Document the specific medication used
   • Assess for known ototoxic agents

4. Perform focused neurological examination 2:

   • Cranial nerves, cerebellar testing (finger-to-nose, heel-to-shin, rapid alternating movements)
   • Gait assessment
   • Look for focal deficits suggesting central pathology

Red Flags Requiring Urgent Evaluation:

Atypical symptoms whose occurrence or persistence warrant further clinical evaluation include subjective hearing loss, gait disturbance, nonpositional vertigo, persistent nausea, or vomiting 1. These may indicate an underlying or concurrent vestibular or CNS disorder 1.

Management Algorithm

If Dix-Hallpike is Positive:

• Perform canalith repositioning procedure (Epley maneuver) immediately 1
• Success rates are approximately 80% with 1-3 treatments 1
• Counsel about fall risk, particularly in elderly patients where BPPV increases fall risk significantly 1, 2

If Dix-Hallpike is Negative but Orthostatic Hypotension Present:

• Address volume status, medication review (diuretics, antihypertensives, cardiovascular medications) 1
• Consider autonomic dysfunction evaluation if persistent

If Both Tests Negative:

• Consider vestibular rehabilitation therapy for persistent disequilibrium 3, 4
• Re-evaluate after discontinuing ear drops to assess if symptoms were medication-related
• If symptoms persist or worsen, consider referral to otolaryngology or neurology 1

Critical Pitfalls to Avoid

1. Never assume absence of room-spinning excludes BPPV—up to 50% present with atypical symptoms 1

2. Do not ignore the ear drop temporal relationship—this suggests either ototoxicity or exacerbation of underlying pathology 1

3. Failure to respond to conservative management should raise concern that the underlying diagnosis may not be BPPV 1

4. Always assess fall risk in patients with positional dizziness, as this increases fall risk 12-fold in elderly patients 2

5. Consider concurrent diagnoses—BPPV can coexist with other vestibular or cardiovascular disorders 1