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

Initial Workup for Dizziness in the Emergency Room

The initial workup for dizziness in the emergency room should focus on categorizing the dizziness by timing and triggers, followed by targeted physical examination including the HINTS test for acute vestibular syndrome, to distinguish between benign peripheral causes and potentially life-threatening central causes. 1, 2

Step 1: Categorize the Dizziness by Timing and Triggers

Categorizing dizziness by timing and triggers is more useful than focusing on symptom quality (vertigo, lightheadedness, etc.) 1, 2:

1. Acute Vestibular Syndrome (AVS):

   • Continuous dizziness lasting days to weeks
   • Associated with nausea, vomiting, head motion intolerance
   • Common causes: Vestibular neuritis, labyrinthitis, posterior circulation stroke

2. Triggered Episodic Vestibular Syndrome:

   • Brief episodes triggered by specific actions (usually position changes)
   • Episodes typically last <1 minute
   • Common causes: Benign Paroxysmal Positional Vertigo (BPPV), central paroxysmal positional vertigo

3. Spontaneous Episodic Vestibular Syndrome:

   • Episodes not triggered by specific actions
   • Lasts minutes to hours
   • Common causes: Vestibular migraine, Ménière's disease, TIA

4. Chronic Vestibular Syndrome:

   • Dizziness lasting weeks to months
   • Common causes: Anxiety, medication side effects, posterior fossa masses

Step 2: Targeted Physical Examination

For Acute Vestibular Syndrome:

• HINTS examination (critical for distinguishing peripheral from central causes):
  • Head Impulse test: Abnormal (catch-up saccade) suggests peripheral cause
  • Nystagmus: Direction-changing, vertical, or pure torsional suggests central cause
  • Test of Skew: Vertical misalignment suggests central cause
  • When performed by trained clinicians, HINTS has 92.9% sensitivity and 83.4% specificity for central causes 3
  • HINTS+ (adding hearing assessment) increases sensitivity to 99% 3

For Triggered Episodic Vestibular Syndrome:

• Dix-Hallpike maneuver: Tests for posterior canal BPPV
• Supine roll test: Tests for horizontal canal BPPV

For All Patients:

• Vital signs (including orthostatics)
• Focused neurological examination (cranial nerves, cerebellar function, gait)
• Cardiovascular examination

Step 3: Risk Stratification

High-Risk Features Requiring Immediate Attention:

• Abnormal HINTS exam suggesting central cause
• Focal neurological deficits
• New-onset severe headache
• Vascular risk factors with acute persistent vertigo
• Inability to stand or walk

Moderate-Risk Features:

• First episode of severe vertigo
• Age >60 with vascular risk factors
• Hearing loss with vertigo

Step 4: Diagnostic Testing

Imaging:

• MRI head without IV contrast: Indicated for:

  • AVS with abnormal HINTS exam or neurological deficits
  • High vascular risk patients with AVS even with normal exam
  • Not routinely indicated for typical BPPV with positive Dix-Hallpike 1

• CT head without IV contrast:

  • Less sensitive than MRI, especially for posterior fossa lesions
  • Consider when MRI not immediately available for high-risk patients
  • Low yield (<1%) in isolated dizziness without neurological deficits 1

Laboratory Testing:

• Targeted based on history and examination:
  • Complete blood count if anemia or infection suspected
  • Electrolytes, glucose if metabolic causes suspected
  • Cardiac enzymes if cardiac etiology suspected

Common Pitfalls to Avoid:

1. Relying solely on symptom quality (vertigo vs. lightheadedness) rather than timing and triggers
2. Overreliance on CT imaging which has poor sensitivity for posterior fossa strokes
3. Failure to perform HINTS examination in acute vestibular syndrome
4. Assuming all positional vertigo is BPPV without considering central causes
5. Attributing dizziness to "dehydration" or "viral syndrome" without adequate evaluation

Special Considerations:

• Orthostatic hypotension: Consider midodrine for symptomatic management if this is the cause 4
• Vestibular suppressants (e.g., meclizine): May be helpful for symptomatic relief in peripheral causes but should be used cautiously as they can delay central compensation 5
• Posterior circulation stroke: Can present with isolated dizziness in up to 25% of cases; prevalence increases to 75% in high vascular risk cohorts 1

By following this systematic approach, emergency physicians can efficiently distinguish between benign peripheral causes and potentially life-threatening central causes of dizziness, ensuring appropriate management and disposition.