What is the recommended approach for evaluating dizziness?

Recommended Approach for Evaluating Dizziness

The evaluation of dizziness should focus on timing and triggers rather than symptom quality, using a structured approach that categorizes dizziness into specific vestibular syndromes and includes targeted physical examination techniques such as the HINTS examination to differentiate between peripheral and central causes. 1

Initial Assessment Framework

Categorization by Timing and Triggers

1. Acute Vestibular Syndrome (AVS)

   • Acute persistent continuous dizziness lasting days to weeks
   • Associated with nausea, vomiting, and head motion intolerance
   • Requires HINTS examination to differentiate peripheral from central causes 1

2. Triggered Episodic Vestibular Syndrome

   • Episodic dizziness triggered by specific actions (e.g., BPPV)
   • Evaluate with Dix-Hallpike maneuver 1, 2

3. Spontaneous Episodic Vestibular Syndrome

   • Untriggered episodic dizziness lasting minutes to hours
   • Consider Menière's disease, vestibular migraine 3, 1

4. Chronic Vestibular Syndrome

   • Dizziness lasting weeks to months or longer 1

Key Physical Examination Components

HINTS Examination (for Acute Vestibular Syndrome)

• Head-Impulse Test: Abnormal (corrective saccade) suggests peripheral cause; normal suggests central cause
• Nystagmus Pattern: Unidirectional horizontal nystagmus suggests peripheral cause; bidirectional or vertical/torsional nystagmus suggests central cause
• Test of Skew: Vertical misalignment suggests central cause 1

Other Essential Examination Elements

• Dix-Hallpike maneuver for suspected BPPV 1, 2
• Orthostatic blood pressure measurement (supine, then standing after 1-3 minutes) to identify orthostatic hypotension (drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg) 1
• Cardiovascular examination including heart rate, rhythm, and abnormal heart sounds 1
• Neurological examination including cranial nerves, motor strength, coordination, and gait assessment 1

Diagnostic Testing

Imaging

• MRI brain (without contrast) indicated for:

  • AVS with abnormal HINTS examination
  • AVS with neurological deficits
  • High vascular risk patients with AVS even with normal examination
  • Chronic undiagnosed dizziness not responding to treatment 1

• CT head without contrast may be considered when MRI is unavailable, but has low sensitivity (20-40%) for posterior fossa lesions 1

• No imaging needed for HINTS-negative acute vestibular syndrome (risk of acute brain lesions is 0%) 1

Laboratory Testing

• Generally not required and usually not helpful for initial evaluation 4, 2
• Consider targeted testing based on suspected etiology

Evaluation of Common Causes

Peripheral Vestibular Disorders

1. Benign Paroxysmal Positional Vertigo (BPPV)

   • Brief vertigo triggered by head position changes
   • Positive Dix-Hallpike maneuver 1, 2

2. Vestibular Neuritis

   • Acute onset vertigo lasting days
   • Abnormal head impulse test, unidirectional nystagmus 1

3. Menière's Disease

   • Episodic vertigo with fluctuating hearing loss, tinnitus, and aural fullness
   • Episodes typically last hours 3, 1

4. Vestibular Migraine

   • History of migraine headaches
   • Vertigo episodes of variable duration
   • May have light sensitivity and motion intolerance
   • Hearing loss mild or absent and stable over time 3

Central Causes (Require Urgent Evaluation)

1. Posterior circulation stroke/TIA (accounts for 25% of AVS cases, up to 75% in high vascular risk cohorts)
2. Multiple sclerosis (accounts for 4% of AVS cases)
3. Cerebellar hemorrhage
4. Central paroxysmal positional vertigo
5. Demyelinating diseases 1

Common Pitfalls to Avoid

• Relying solely on symptom quality rather than timing and triggers 1
• Overreliance on CT imaging due to poor sensitivity for posterior fossa lesions 1
• Missing stroke in isolated AVS (11% of patients with acute persistent vertigo but no focal neurologic symptoms have stroke) 1
• Failure to recognize that 75-80% of patients with AVS related to infarct have no associated focal neurologic deficits 1
• Overuse of vestibular suppressants which can delay central compensation 1

Red Flags Requiring Urgent Evaluation

• Acute onset severe headache
• Ataxia symptoms
• History of previous stroke
• Diabetes mellitus
• Abnormal HINTS examination
• Associated neurological deficits 1

By following this structured approach to dizziness evaluation, clinicians can effectively differentiate between benign peripheral causes and potentially life-threatening central causes, ensuring appropriate management and timely referral when needed.