What finding suggests a central rather than peripheral etiology of vertigo (dizziness) in a patient presenting with a sensation of spinning?

Central vs Peripheral Vertigo: Distinguishing Features

Constant dizziness (Option A) is the finding that suggests a central rather than peripheral etiology in this patient with progressive vertigo. 1

Key Distinguishing Features

Nystagmus Characteristics That Indicate Central Pathology

Central vertigo produces nystagmus that does NOT fatigue with repeated testing, making Option B (horizontal nystagmus that fatigues) actually suggestive of a peripheral cause, not central. 2, 1 The American Academy of Otolaryngology-Head and Neck Surgery specifically identifies the following nystagmus patterns as indicating central pathology:

• Pure vertical nystagmus (upbeating or downbeating) without torsional component 2, 1
• Direction-changing nystagmus occurring without changes in head position (periodic alternating nystagmus) 2
• Baseline nystagmus present without provocative maneuvers 2, 1
• Down-beating nystagmus on Dix-Hallpike maneuver without torsional component 2, 1
• Nystagmus that is NOT suppressed by visual fixation 1, 3
• Nystagmus that does NOT fatigue and persists without modification during repositioning 2, 1, 3

In contrast, peripheral vertigo produces horizontal nystagmus with rotatory component that IS unidirectional, suppressed by visual fixation, and fatigable with repeated testing. 1

Temporal Pattern: A Critical Distinguishing Factor

The progressive, constant nature of this patient's symptoms over several days strongly suggests central pathology. 1, 3 The American Academy of Otolaryngology-Head and Neck Surgery provides clear temporal distinctions:

• Vertebrobasilar insufficiency (central): Episodes typically last less than 30 minutes 2, 1, 3
• BPPV (peripheral): Episodes last less than 1 minute 1, 3
• Ménière's disease (peripheral): Sustained attacks lasting hours 1
• Vestibular neuritis (peripheral): Acute onset lasting days to weeks but typically with acute onset, not progressive worsening 1

The progressive worsening over several days with constant symptoms is atypical for common peripheral causes and raises concern for central pathology such as cerebellar infarction or posterior fossa lesion. 3

Why the Other Options Suggest Peripheral Pathology

Bilateral hearing loss (Option C) and tinnitus (Option D) are NOT distinguishing features between central and peripheral causes, as both can occur with peripheral vestibular disorders:

• Ménière's disease presents with fluctuating hearing loss, tinnitus, and aural fullness 2, 1
• Labyrinthitis causes vertigo with associated hearing loss 1
• Vertebrobasilar insufficiency (central) typically has NO associated hearing loss 2, 1

Critical Red Flags for Central Pathology

Beyond constant dizziness, clinicians must assess for:

• Additional neurological symptoms: dysarthria, dysmetria, dysphagia, sensory or motor deficits, diplopia, or Horner's syndrome 1
• Severe postural instability out of proportion to nystagmus 2, 1
• Failure to respond to peripheral vertigo treatments (canalith repositioning, vestibular rehabilitation) 2, 1
• New-onset severe headache with vertigo suggesting vertebrobasilar stroke or hemorrhage 1

Common Pitfall to Avoid

Cerebellar infarction can masquerade as peripheral vestibular lesion because vertigo and severe imbalance may be the only presenting features without other obvious neurological signs. 3 MRI is indicated in any patient with acute vertigo and profound imbalance suspected to be cerebellar infarct or hemorrhage. 3 The progressive, constant nature of this patient's symptoms over several days warrants urgent neuroimaging to exclude central pathology. 1, 3