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

Initial Workup for Dizziness

The initial workup for dizziness should focus on timing and triggers rather than symptom quality, including a targeted history, physical examination with orthostatic blood pressure measurements, neurological assessment, and vestibular examination with the Dix-Hallpike maneuver and HINTS examination. 1

Categorizing Dizziness by Timing and Triggers

The American Academy of Otolaryngology-Head and Neck Surgery recommends categorizing dizziness into four vestibular syndromes based on timing and triggers 1:

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

   • Key evaluation: HINTS examination (Head Impulse, Nystagmus, Test-of-Skew)
   • Common causes: Vestibular neuritis, labyrinthitis, stroke

2. Triggered Episodic Vestibular Syndrome (t-EVS): Brief episodes triggered by position changes

   • Key evaluation: Dix-Hallpike maneuver, supine roll test
   • Common cause: Benign Paroxysmal Positional Vertigo (BPPV)

3. Spontaneous Episodic Vestibular Syndrome (s-EVS): Recurrent episodes without clear triggers

   • Key evaluation: Assess for hearing loss, tinnitus, aural fullness
   • Common causes: Menière's disease, vestibular migraine, TIA

4. Chronic Vestibular Syndrome: Persistent dizziness lasting months

   • Key evaluation: Assess for underlying conditions
   • Common causes: Medication side effects, psychiatric disorders

Essential Components of Initial Evaluation

1. Targeted History

• Timing: onset, duration, frequency
• Triggers: positional changes, specific movements, activities
• Associated symptoms: hearing loss, tinnitus, headache, neurological symptoms
• Medications review: focus on those that can cause dizziness
• Past medical history: vascular risk factors, migraine, psychiatric disorders 1, 2

2. Physical Examination

Vital Signs and Orthostatic Testing

• Measure blood pressure supine for 5 minutes, then immediately upon standing, and again at 1 and 3 minutes
• Orthostatic hypotension: ≥20 mmHg drop in systolic or ≥10 mmHg drop in diastolic BP 1

Vestibular Examination

• Nystagmus assessment: Observe for spontaneous, gaze-evoked, or positional nystagmus
• Dix-Hallpike maneuver: For suspected BPPV
• HINTS examination: For acute vestibular syndrome to differentiate peripheral from central causes
  • Head Impulse test: Abnormal (catch-up saccade) suggests peripheral cause
  • Nystagmus: Direction-changing nystagmus suggests central cause
  • Test of Skew: Vertical misalignment suggests central cause 1, 3

Neurological Examination

• Cranial nerves
• Motor strength and coordination
• Gait and balance assessment
• Cerebellar testing 1, 2

3. Initial Testing

• 12-lead ECG to rule out cardiac causes 1
• Basic laboratory tests:
  • Complete blood count
  • Basic metabolic panel
  • Blood glucose
  • Thyroid function tests 1

Red Flags Requiring Urgent Evaluation

Be alert for signs suggesting central rather than peripheral causes:

• Downbeating or direction-changing nystagmus
• Abnormal HINTS examination
• Associated neurological symptoms
• Severe imbalance out of proportion to vertigo
• Sudden severe headache with dizziness
• Persistent vomiting
• Altered mental status 1

Imaging and Advanced Testing

Imaging is not routinely indicated but should be considered in specific scenarios:

• MRI brain (without contrast) is indicated for:

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

• Non-contrast head CT is recommended if suspicion for subarachnoid hemorrhage is high 1

Common Diagnostic Pitfalls

1. Relying on symptom quality alone: Focus on timing and triggers rather than how patients describe their dizziness 3

2. Missing stroke in AVS: Up to 25% of strokes presenting with isolated dizziness can be missed if HINTS examination is not performed 1, 3

3. Overuse of imaging: MRI is not necessary for most cases of dizziness with clear peripheral causes 1, 2

4. Inadequate medication review: Many medications can cause dizziness; always perform a thorough medication review 4

5. Failure to recognize BPPV: This common and treatable condition is often missed without proper positional testing 1, 2

By following this systematic approach based on timing and triggers, clinicians can efficiently narrow the differential diagnosis and determine appropriate management for patients presenting with dizziness.