Diagnosis of Vestibular Neuritis: HINTS Examination Not Required
A positive HINTS examination is not required for the diagnosis of vestibular neuritis, which is primarily a clinical diagnosis based on characteristic symptoms and exclusion of central causes. 1
Diagnostic Criteria for Vestibular Neuritis
Vestibular neuritis is characterized by:
- Abrupt onset of true-whirling vertigo lasting more than 24 hours
- Associated symptoms: nausea, vomiting, head motion intolerance, gait unsteadiness
- Absence of cochlear symptoms (hearing loss, tinnitus)
- Absence of other neurological symptoms or signs 2
Key Diagnostic Elements
- Clinical Presentation: The diagnosis is primarily based on the characteristic clinical features
- HINTS Examination: While useful for differentiating peripheral from central causes, a positive HINTS is not mandatory for diagnosis 1, 3
- Imaging: MRI is not required to establish the diagnosis of vestibular neuritis 1
Role of HINTS Examination
The HINTS examination serves a different purpose than diagnosing vestibular neuritis itself:
- It helps differentiate peripheral causes (like vestibular neuritis) from central causes (like stroke)
- A peripheral pattern on HINTS (positive head impulse test, direction-fixed nystagmus, no skew deviation) supports vestibular neuritis 3, 4
- A central pattern on HINTS warrants further investigation for stroke
HINTS Components and Interpretation for Vestibular Neuritis
- Head Impulse Test: Typically abnormal (positive) in vestibular neuritis
- Nystagmus: Direction-fixed, horizontal-torsional nystagmus that does not change direction with gaze
- Test of Skew: Typically negative (no vertical misalignment) in vestibular neuritis
Diagnostic Confirmation
While not required for diagnosis, these findings can support vestibular neuritis:
- MRI Findings: May show decreased caliber of the vestibular nerve or enhancement following gadolinium administration, but these are not always present 1
- Caloric Testing: Often shows reduced or absent caloric response on the affected side
- Video Head Impulse Test (v-HIT): Shows reduced VOR gain in the affected semicircular canals 5
Clinical Pearls and Pitfalls
- Pitfall: Relying solely on HINTS to diagnose vestibular neuritis can be misleading, as its primary purpose is to rule out stroke
- Caution: When performed by emergency physicians rather than neurologists, HINTS has lower sensitivity (83%) and specificity (44%) for differentiating central from peripheral causes 6
- Important: Vestibular neuritis is the third most common peripheral vestibular disorder after BPPV and Ménière's disease 2
- Remember: About 25% of acute vestibular syndrome cases are caused by stroke, with higher prevalence in high vascular risk patients 3, 7
In conclusion, while HINTS examination is a valuable tool for differentiating peripheral from central causes of vertigo, it is not a requirement for diagnosing vestibular neuritis. The diagnosis remains primarily clinical, based on characteristic symptoms and the absence of central or cochlear involvement.