What is the initial workup for a patient presenting with dizziness?

Diagnostic Approach to Dizziness

The evaluation of dizziness should focus on timing and triggers, neurological examination including HINTS (Head-Impulse, Nystagmus, Test of Skew) to differentiate peripheral from central causes, and targeted testing based on specific clinical findings rather than routine blood work or imaging. 1

Initial Categorization by Timing and Triggers

Categorize the patient's dizziness into one of three patterns:

1. Acute Vestibular Syndrome (AVS): Continuous dizziness lasting days

   • Perform HINTS examination (superior to imaging for stroke detection)
   • Abnormal HINTS or neurological deficits require MRI brain
   • Normal HINTS suggests peripheral cause (e.g., vestibular neuritis)

2. Spontaneous Episodic Vestibular Syndrome: Recurrent episodes without clear trigger

   • Assess for associated symptoms (headache, hearing loss)
   • Consider vestibular migraine, Meniere's disease, or TIA

3. Triggered Episodic Vestibular Syndrome: Episodes provoked by specific triggers

   • Perform Dix-Hallpike maneuver for positional vertigo
   • Perform supine roll test for lateral canal BPPV

Physical Examination Components

• Vital signs: Including orthostatic blood pressure measurements
• Neurological examination: Complete cranial nerve assessment, motor strength, coordination, gait
• Vestibular assessment:
  • Nystagmus evaluation (direction, triggers)
  • Dix-Hallpike maneuver for posterior canal BPPV
  • Supine roll test for lateral canal BPPV
  • HINTS examination for AVS:
    • Head impulse test (abnormal = peripheral)
    • Nystagmus pattern (direction-changing = central)
    • Test of skew (vertical misalignment = central)

Red Flags Requiring Urgent Evaluation

• Direction-changing nystagmus without head position changes
• Downbeating nystagmus on Dix-Hallpike
• Baseline nystagmus without provocative maneuvers
• Failure to respond to appropriate repositioning maneuvers
• Associated neurological symptoms or signs
• New-onset severe headache
• High vascular risk patients with acute vestibular syndrome

Laboratory Testing

Laboratory tests should be ordered selectively based on clinical suspicion:

• CBC: When anemia is suspected
• Electrolytes and renal function: For patients on medications affecting electrolytes
• Blood glucose/HbA1c: For patients with diabetes or risk factors
• No routine blood work is recommended for isolated dizziness 1

Imaging

• MRI brain without contrast: Preferred when imaging is indicated
  • Higher sensitivity for central causes compared to CT (CT has only 28.5% sensitivity)
  • Indicated for AVS with abnormal HINTS, neurological deficits, high vascular risk
• CT head: Very low diagnostic yield (2.2%) for acute dizziness
• Routine imaging has low yield in isolated dizziness without neurological deficits (<1% for CT, 4% for MRI) 1

Common Pitfalls to Avoid

1. Overreliance on imaging: Early imaging may miss approximately 20% of strokes
2. Overuse of vestibular suppressants: Can delay central compensation
3. Failure to perform appropriate positional testing: Dix-Hallpike and supine roll tests are essential
4. Missing red flags for central causes: Neurological symptoms require further evaluation
5. Inadequate patient counseling: Can lead to poor outcomes and increased fall risk

Treatment Considerations

For BPPV:

• Canalith repositioning procedure (Epley maneuver) for posterior canal BPPV
• Appropriate roll maneuvers for lateral canal BPPV

For vestibular neuritis:

• Short-term vestibular suppressants (e.g., meclizine 25-100 mg daily in divided doses) 2
• Vestibular rehabilitation

For Meniere's disease:

• Salt restriction and diuretics
• Consider referral to otolaryngology

For central causes:

• Urgent neurological evaluation
• Appropriate management based on etiology

Patient Education

• Counsel regarding fall risk, especially in elderly patients
• Inform about recurrence rates (15% per year, up to 50% at 5 years)
• Warn about drowsiness with vestibular suppressants like meclizine 2
• Advise against driving or operating dangerous machinery while taking vestibular suppressants
• Caution against alcohol consumption with medications like meclizine 2