EM Command Center / Neurology & Psychiatry • 3 min read • 4 sections

Acute Vertigo & The HINTS Protocol

Evidence-based emergency management of the acutely dizzy patient. Details the timing and triggers framework (TiTrATE), the three-step HINTS examination (Head Impulse, Nystagmus, Test of Skew) to differentiate vestibular neuritis from posterior circulation cerebellar/brainstem stroke, and canalith repositioning (Epley maneuver) for BPPV.

Resuscitation Quick Ribbon (First 2 Minutes)

High-Acuity

Apply TiTrATE framework:Is vertigo Triggered episodic (BPPV), Spontaneous episodic (Meniere, TIA), or Continuous / Acute Vestibular Syndrome (AVS)?

Resus:Perform HINTS exam ONLY in patients with continuous vertigo, active spontaneous nystagmus, and motion intolerance (Acute Vestibular Syndrome).

INFARCT mnemonic for central cerebellar stroke:Impulse Normal, Fast-phase Alternating (direction-changing nystagmus), Refixation on Cover Test (vertical skew).

Any single central sign = STROKE:Normal Head Impulse Test OR Direction-Changing Nystagmus OR Vertical Skew Deviation -> Emergent CTA Head/Neck + Stroke Activation.

Benign Paroxysmal Positional Vertigo (BPPV):Triggered by head movement, lasting < 60 seconds; diagnose with Dix-Hallpike maneuver; treat with Epley canalith repositioning.

Bottom-Line Clinical Pearl

In acute vestibular syndrome, the 3-step HINTS exam is MORE SENSITIVE than diffusion-weighted MRI within the first 24-48 hours (sensitivity 99% vs 88%) for detecting acute posterior circulation ischemic stroke.

1. The TiTrATE Diagnostic Framework

Emergency diagnosis of dizziness should be based on Timing and Triggers rather than subjective patient descriptions ('lightheaded' vs 'spinning'):

Syndrome Category	Timing & Triggers	Most Common Benign Cause	Most Dangerous Central Cause
Triggered Episodic	Brief episodes (seconds to minutes) triggered strictly by head position changes	Benign Paroxysmal Positional Vertigo (BPPV)	Central positional nystagmus (posterior fossa mass/stroke)
Spontaneous Episodic	Recurrent episodes (minutes to hours) occurring without movement triggers	Vestibular Migraine, Meniere's Disease	Transient Ischemic Attack (vertebrobasilar TIA), Cardiac Dysrhythmia
Continuous / Acute Vestibular Syndrome (AVS)	Persistent dizziness lasting days to weeks, accompanied by nausea, vomiting, nystagmus, and gait instability	Vestibular Neuritis / Labyrinthitis	Posterior Circulation Cerebellar or Brainstem Stroke (PICA/AICA)

2. The 3-Step HINTS Examination Protocol

The HINTS exam (Head Impulse, Nystagmus, Test of Skew) applies STRICTLY to patients with ongoing Acute Vestibular Syndrome (active nystagmus and continuous vertigo). It evaluates for central cerebellar/brainstem infarction:

HINTS Step	Peripheral Finding (Vestibular Neuritis)	Central Finding (STROKE) - 'INFARCT'
1. Head Impulse Test (HIT)	ABNORMAL (Catch-up Saccade): Patient's eyes move off target when head is rapidly rotated 10-20 degrees, followed by a corrective saccade back to examiner's nose (vestibulo-ocular reflex is impaired).	NORMAL (No Saccade): Patient's eyes remain locked on examiner's nose despite rapid head thrust. Indicates an intact peripheral VOR with a central lesion.
2. Nystagmus Evaluation	UNIDIRECTIONAL / HORIZONTAL: Fast phase beats in only ONE direction regardless of gaze (e.g., right-beating in primary, left, and right gaze). Intensity increases when looking in direction of fast phase (Alexander's law).	DIRECTION-CHANGING (Fast-phase Alternating): Fast phase beats to the right on rightward gaze, and to the left on leftward gaze. Pure vertical (upbeat/downbeat) or torsional nystagmus is ALWAYS central.
3. Test of Skew (Alternate Cover)	NO SKEW: Eyes remain stationary when cover is rapidly switched from one eye to the other.	VERTICAL SKEW DEVIATION: One eye is elevated and the other depressed; when uncovering, the eye makes a vertical corrective realignment (refixation).

Critical Pitfall / Contraindication

The INFARCT Rule: In an Acute Vestibular Syndrome patient, ANY ONE of the following three signs indicates a CENTRAL STROKE: (1) Impulse Normal (I-N); (2) Fast-phase Alternating nystagmus (F-A); (3) Refixation on Cover Test / Skew (R-C-T). A normal Head Impulse Test in AVS is the most dangerous sign of all, signifying central stroke.

3. The Plus Test: New-Onset Hearing Loss (HINTS Plus)

Adding bedside hearing evaluation (finger rub or whisper) creates HINTS Plus. New acute unilateral sensorineural hearing loss in AVS strongly points to an Anterior Inferior Cerebellar Artery (AICA) infarction involving the internal auditory artery (labyrinthine artery) supplying the cochlea and vestibular labyrinth.

4. Benign Paroxysmal Positional Vertigo (BPPV)

Pathology: Canalithiasis (free-floating calcium carbonate otoconia) within the posterior semicircular canal (85-95% of BPPV cases).
Dix-Hallpike Test: Turn patient's head 45 degrees to one side; rapidly lower patient into supine position with neck extended 20 degrees. Positive test: Latency of 2-5 seconds, followed by crescendo-decrescendo torsional/upbeating nystagmus lasting < 60 seconds, accompanied by intense vertigo.
Epley Canalith Repositioning Maneuver: 4 positions held for 30-60 seconds each: (1) Dix-Hallpike position; (2) Rotate head 90 degrees to contralateral side; (3) Roll patient onto shoulder facing down 45 degrees toward floor; (4) Sit patient upright with chin tucked. Success rate > 80-90% on first attempt.
Meclizine / Antihistamine Rule: Vestibular suppressants (meclizine, dimenhydrinate, benzodiazepines) are INEFFECTIVE for BPPV and impair central vestibular compensation. Treat with the Epley maneuver, not sedating drugs.

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