What diagnostic studies are recommended for evaluating dizziness?

Diagnostic Studies for Evaluation of Dizziness

Diagnostic testing for dizziness should be targeted based on clinical presentation rather than routinely performed, with imaging and vestibular function testing reserved for specific indications rather than used as screening tools. 1

Initial Assessment

• History and physical examination: Should focus on timing, triggers, and associated symptoms to classify dizziness into one of four categories: vertigo, presyncope, disequilibrium, or lightheadedness 1, 2
• Neurological examination: Complete evaluation including cranial nerves, coordination, and gait 1
• Cardiovascular examination: Including orthostatic blood pressure and heart rate measurements 1
• HINTS examination (Head-Impulse, Nystagmus, Test of Skew): Critical for differentiating peripheral from central causes of acute vestibular syndrome 1, 3
• Dix-Hallpike maneuver: For patients with positional/triggered dizziness to diagnose BPPV 2

Laboratory Testing

• Targeted approach: Laboratory tests should not be ordered routinely but based on clinical suspicion 1
• Consider selectively:
  • Blood glucose (supported as a routine test in all dizzy patients) 4
  • Complete blood count
  • Electrolytes
  • Toxicology screening when indicated 1

Imaging Studies

• MRI brain (without contrast) is indicated for:

  • Acute Vestibular Syndrome (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

• Neuroimaging should NOT be routinely used to confirm diagnosis of BPPV 5

Vestibular Function Testing

• Not indicated when patients meet clinical criteria for BPPV 5
• Indicated when:
  • Diagnosis of vertiginous/dizziness syndrome is unclear
  • Patient remains symptomatic following treatment
  • Multiple concurrent peripheral vestibular disorders are suspected 5

Cardiac Testing

• Cardiac rhythm monitoring: Recommended for patients age 45 and older 4
• ECG: Consider for patients with presyncope or risk factors for cardiac disease 1

Audiometric Testing

• No specific recommendation is made concerning audiometric testing in patients diagnosed with BPPV due to insufficient evidence for its diagnostic or prognostic value 5

Specialized Testing Based on Clinical Category

For Vertigo

• Dix-Hallpike maneuver (for BPPV)
• HINTS examination (for acute vestibular syndrome)
• Consider MRI if central cause suspected

For Presyncope

• Orthostatic vital signs
• ECG
• Consider cardiac monitoring

For Disequilibrium

• Focused neurological examination
• Consider MRI if central neurological cause suspected

Common Pitfalls to Avoid

• Overreliance on symptom quality: Focus on timing and triggers rather than how patients describe their dizziness 2
• Routine testing: Valsalva, carotid stimulation, Romberg and Quix tests, mental status examination, CBC, electrolytes, and BUN have low yield and should be done selectively 4
• Unnecessary imaging: Neuroimaging is rarely indicated for typical BPPV and adds significant cost without changing management 5
• Missing serious causes: Best predicted by older age, lack of vertigo, or neurologic deficit (86% sensitivity for "serious" dizziness) 4

Remember that dizziness is usually a benign, self-limited complaint with peripheral vestibulopathies (35-55%) and psychiatric disorders (10-25%) being the most common causes, while cerebrovascular disease (5%) and brain tumors (<1%) are relatively infrequent 6.