What is the approach to evaluating dizziness?

Approach to Evaluating Dizziness

The evaluation of dizziness should be based on timing and triggers rather than the patient's subjective description of symptom quality, categorizing patients into specific vestibular syndromes that guide targeted bedside examination and determine the need for imaging. 1, 2

Initial Categorization by Timing and Triggers

The American Academy of Otolaryngology-Head and Neck Surgery recommends classifying dizziness into four vestibular syndromes based on temporal patterns and precipitating factors 2, 3:

• Acute Vestibular Syndrome (AVS): Acute persistent dizziness lasting days to weeks 2
• Triggered Episodic Vestibular Syndrome: Brief episodes provoked by specific movements or positions 4, 5
• Spontaneous Episodic Vestibular Syndrome: Recurrent episodes without clear triggers 4, 5
• Chronic Vestibular Syndrome: Persistent symptoms lasting months 3

This timing-and-triggers approach is superior to the outdated method of categorizing dizziness by symptom quality (vertigo, presyncope, disequilibrium, lightheadedness), which does not effectively distinguish benign from dangerous causes 4, 5.

Critical History Elements

Focus on duration, onset pattern, and positional triggers rather than asking patients to describe their dizziness type. 2

Key questions include:

• Duration of episodes: Seconds suggest BPPV; minutes to hours suggest Ménière's disease or vestibular migraine; days suggest vestibular neuritis or stroke 4, 5
• Positional triggers: Head movements triggering symptoms suggest BPPV 2
• Associated symptoms: Hearing loss or tinnitus suggests Ménière's disease; headache suggests vestibular migraine; neurological symptoms (diplopia, dysarthria, numbness, weakness) suggest central causes 2, 3

Targeted Physical Examination

All patients with dizziness should be examined for spontaneous nystagmus. 2

For Triggered Episodic Vestibular Syndrome (Suspected BPPV):

• Perform Dix-Hallpike maneuver to assess for posterior canal BPPV 2
• Perform supine roll test to assess for horizontal canal BPPV 2, 4

For Acute Vestibular Syndrome (Persistent Dizziness):

• Use HINTS examination (Head Impulse, Nystagmus, Test of Skew) to differentiate peripheral vestibular neuritis from central stroke 1, 2
• Bedside physical examination is more sensitive than early MRI for detecting posterior circulation stroke in this context 4, 5

For All Patients:

• Perform orthostatic blood pressure testing if presyncope is suspected 6
• Assess gait and balance 3

Imaging Decisions

Imaging is not routinely indicated for most cases of dizziness and should be reserved for specific clinical scenarios. 2

When Imaging is NOT Needed:

• Isolated dizziness without neurological symptoms has extremely low imaging yield (CT <1%, MRI 4%) 1
• Clear peripheral causes like BPPV confirmed by Dix-Hallpike maneuver 2
• Lightheadedness from systemic causes (dehydration, hypotension, vasovagal reaction, anxiety) diagnosed clinically 1

When Imaging IS Indicated:

• Focal neurological deficits present 3
• HINTS examination suggests central cause 2
• Unilateral tinnitus or asymmetric hearing loss 3
• Sudden hearing loss 3
• Inability to stand or walk 3
• Downbeating nystagmus or other central nystagmus patterns 3
• Failure to respond to appropriate vestibular treatments 3

Preferred Imaging Modality:

• MRI brain with diffusion-weighted imaging (DWI) is preferred over CT when stroke is suspected, though even MRI has only moderate yield (9%) in delayed imaging for transient vestibular syndrome 1
• CT head has very low sensitivity (20-40%) for detecting causative etiology despite high negative predictive value (90%) 1
• CTA head and neck has low diagnostic yield (3%) in isolated dizziness and adds no information beyond noncontrast CT 1

Common Pitfalls to Avoid

Do not rely on patient descriptions of "dizziness type" to guide your evaluation, as this approach is inconsistent with current evidence and does not distinguish benign from dangerous causes 4, 5.

Do not order routine imaging for isolated dizziness without neurological findings, as the yield is extremely low and leads to unnecessary radiation exposure and cost 1, 2.

Do not assume absence of focal neurological deficits rules out stroke, as 4% of isolated dizziness cases in the emergency department are due to stroke 2. Use HINTS examination in patients with acute vestibular syndrome 2.

Do not fail to perform appropriate bedside tests (Dix-Hallpike, supine roll test, HINTS) before ordering imaging, as these tests are more diagnostically useful than imaging in most cases 2, 3.

Do not miss orthostatic hypotension as a cause, particularly in patients with autonomic dysfunction, which can present as persistent isolated dizziness even without apparent orthostatic symptoms 1.