What is the initial management and evaluation for a patient presenting with acute dizziness?

HINTS Examination in Acute Dizziness

The HINTS examination (Head Impulse, Nystagmus, Test of Skew) is the most critical bedside tool for distinguishing dangerous posterior circulation stroke from benign peripheral vertigo in patients with acute vestibular syndrome, but it must be performed by specially trained practitioners to achieve its reported 100% sensitivity for stroke detection. 1, 2

What is the HINTS Examination?

The HINTS examination consists of three components used to evaluate patients with acute persistent vertigo:

• Head Impulse Test: Assesses vestibulo-ocular reflex function by rapidly rotating the patient's head while they fixate on a target 2, 3
• Nystagmus Assessment: Evaluates the direction and pattern of involuntary eye movements 2, 3
• Test of Skew: Checks for vertical misalignment of the eyes using alternate cover testing 2, 3

When to Use HINTS

Apply HINTS specifically in patients with acute vestibular syndrome (AVS)—defined as acute persistent vertigo lasting days to weeks with constant symptoms, nausea/vomiting, gait instability, and head-motion intolerance. 1, 2

Do NOT use HINTS for:

• Brief episodic vertigo (seconds to minutes) triggered by head movements—this suggests BPPV and requires Dix-Hallpike testing instead 1, 2
• Spontaneous episodic vertigo (minutes to hours)—this suggests vestibular migraine or TIA 3, 4
• Patients with obvious focal neurological deficits—these patients need immediate imaging regardless 1, 2

Critical Performance Requirements

The HINTS examination is only reliable when performed by specially trained practitioners with expertise in vestibular examination. 1, 2

• When performed by experts, HINTS has 100% sensitivity for posterior circulation stroke versus 46% for early MRI 2
• When performed by non-experts, the results are unreliable and should not guide clinical decisions 1, 2
• Most emergency physicians and general practitioners lack adequate training to perform HINTS reliably 1, 2

Interpreting HINTS Results

HINTS Suggests CENTRAL (Stroke) Cause When:

• Normal head impulse test (intact vestibulo-ocular reflex)—paradoxically, this suggests stroke because peripheral lesions typically show abnormal head impulse 2, 3
• Direction-changing nystagmus or vertical nystagmus—these patterns indicate brainstem or cerebellar pathology 2, 3
• Positive skew deviation—vertical eye misalignment suggests central pathology 2, 3

HINTS Suggests PERIPHERAL (Benign) Cause When:

• Abnormal head impulse test (corrective saccade present) 2, 3
• Unidirectional horizontal nystagmus 2, 3
• Negative skew deviation 2, 3

Clinical Context and Limitations

Approximately 25% of patients presenting with acute vestibular syndrome have posterior circulation stroke, rising to 75% in high vascular risk cohorts. 1

• Between 75-80% of patients with acute vestibular syndrome from posterior circulation infarct have NO focal neurologic deficits 1, 2
• A normal neurologic examination does NOT exclude stroke in dizzy patients 1, 2
• In one study, 11% of patients with acute persistent vertigo but no focal neurologic signs had acute infarct on imaging 1

Imaging Decisions Based on HINTS

NO imaging indicated when:

• HINTS examination by trained examiner is consistent with peripheral vertigo AND
• Normal neurologic examination AND
• Low vascular risk profile 1, 2

MRI head without contrast indicated when:

• HINTS examination suggests central cause 1, 2
• Abnormal neurologic examination 1, 2
• High vascular risk patients (age >50, hypertension, diabetes, prior stroke/TIA, atrial fibrillation) 1, 2
• HINTS performed by non-expert examiner 1, 2

Common Pitfall:

CT head has extremely low sensitivity for posterior circulation infarcts and should not be used instead of MRI when stroke is suspected in acute vestibular syndrome. 1, 2 Detection rate of contributory CNS pathology on CT in patients with isolated dizziness and normal neurologic exam is less than 1% 1

Red Flags Requiring Immediate Imaging Regardless of HINTS

• New severe headache 2
• Sudden hearing loss 2, 5
• Inability to stand or walk 2, 5
• Downbeating nystagmus or other central nystagmus patterns 2, 5
• Any focal neurological deficits 2, 5

Practical Algorithm

1. Classify timing: Is this acute persistent vertigo (days-weeks constant) versus episodic (seconds-hours)? 2, 3, 4
2. If acute persistent vertigo: Perform complete neurologic examination 2, 5
3. If neurologic exam normal AND trained in HINTS: Perform HINTS examination 1, 2
4. If HINTS suggests peripheral AND low vascular risk: No imaging needed, treat as vestibular neuritis 1, 2
5. If HINTS suggests central OR high vascular risk OR examiner not expert: Obtain MRI head without contrast urgently 1, 2
6. If any red flags present: Immediate imaging and neurology consultation 2, 5