How do you diagnose vestibular neuritis?

Diagnosis of Vestibular Neuritis

Vestibular neuritis is diagnosed through a combination of characteristic clinical presentation of acute severe vertigo lasting days with unidirectional horizontal nystagmus, absence of cochlear and neurological symptoms, and confirmatory vestibular function tests including the head impulse test, caloric testing, and vestibular-evoked myogenic potential testing. 1, 2

Clinical Presentation

The key diagnostic features of vestibular neuritis include:

• Abrupt onset of severe, continuous vertigo lasting more than 24 hours 2
• True-whirling sensation 2
• Unidirectional horizontal nystagmus toward the unaffected ear (with a rotational component) 3
• Absence of hearing loss, tinnitus, or other cochlear symptoms 2
• Absence of other neurological symptoms or signs 2
• Nausea and vomiting 2, 3
• Postural imbalance with tendency to fall toward the affected ear 3

Diagnostic Approach

Step 1: Bedside Examination

• HINTS examination (Head Impulse, Nystagmus, Test of Skew): More sensitive than early MRI for stroke detection 1

  • Head Impulse Test: Pathologic response (catch-up saccade) when testing toward the affected ear 3
  • Nystagmus: Unidirectional horizontal nystagmus that doesn't change direction 1
  • Test of Skew: Normal (no vertical misalignment) 1

• Subjective Visual Vertical Test: Shows deviation toward the affected ear 3

Step 2: Vestibular Function Testing

• Video Head Impulse Test (vHIT): Shows reduced vestibulo-ocular reflex gain on the affected side 4
• Bithermal Caloric Test: Demonstrates canal paresis/reduced response on the affected side 2, 3
• Vestibular-Evoked Myogenic Potential (VEMP): Helps identify selective damage to specific vestibular nerve branches 4

Differential Diagnosis

Critical to rule out central causes of vertigo, particularly:

• Stroke/TIA: Look for abnormal HINTS exam (normal head impulse test, direction-changing nystagmus, skew deviation) 1
• Vestibular Migraine: History of migraine, variable duration, photophobia 1
• Menière's Disease: Episodes with hearing loss, tinnitus, aural fullness 1
• BPPV: Brief positional vertigo with positive Dix-Hallpike test 1

Important Considerations

• Any patient with vascular risk factors presenting with acute vestibular syndrome should be evaluated for possible stroke, even if peripheral signs seem present 5
• Vestibular neuritis is a diagnosis of exclusion 3
• The condition is thought to result from viral infection (likely herpes simplex virus reactivation) affecting the vestibular nerve 2, 4
• Epidemiologically, vestibular neuritis accounts for approximately 41% of vertigo cases in non-specialty settings 1

Common Pitfalls to Avoid

• Failing to perform the HINTS examination, which is crucial for differentiating vestibular neuritis from central causes 1
• Ordering unnecessary imaging studies in patients with clear peripheral vertigo patterns 1
• Missing central causes of vertigo by focusing solely on peripheral symptoms 1
• Prolonged use of vestibular suppressants, which may impede central vestibular compensation 5

By following this diagnostic approach and being aware of the key clinical features, healthcare providers can accurately diagnose vestibular neuritis and distinguish it from more serious central causes of vertigo.