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, vital signs with orthostatic measurements, cardiovascular and neurological examinations, and the HINTS examination when appropriate. 1

Diagnostic Approach

Step 1: Categorize the Dizziness Pattern

• Timing and Triggers (more reliable than symptom quality):
  • Acute Vestibular Syndrome (AVS): Continuous dizziness lasting days to weeks
  • Spontaneous Episodic Vestibular Syndrome: Untriggered episodes lasting minutes to hours
  • Triggered Episodic Vestibular Syndrome: Episodes triggered by specific actions
  • Chronic Vestibular Syndrome: Dizziness lasting weeks to months 1

Step 2: Essential Physical Examination

1. Vital Signs:

   • Blood pressure and heart rate (lying and standing)
   • Define orthostatic hypotension: drop in systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg 1

2. Cardiovascular Examination:

   • Heart rate and rhythm
   • Murmurs or abnormal heart sounds 1

3. Neurological Examination:

   • Cranial nerves
   • Motor strength and coordination
   • Gait assessment 1

4. Vestibular Assessment:

   • HINTS examination for acute vestibular syndrome:
     • Head-Impulse test
     • Nystagmus evaluation
     • Test of Skew
   • Dix-Hallpike maneuver for suspected BPPV 1, 2

Step 3: Targeted Testing Based on Initial Findings

Imaging Indications:

• 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 1

• CT head without contrast:

  • Only when MRI unavailable
  • Note: Low sensitivity (20-40%) for posterior fossa lesions 1

• No imaging needed for HINTS-negative acute vestibular syndrome 1

Laboratory Testing:

• Generally not required for initial evaluation unless specific concerns 2, 3
• Consider based on suspected etiology:
  • CBC if anemia suspected
  • Electrolytes if dehydration or medication effect suspected
  • Glucose if diabetic 3

Common Diagnoses and Specific Evaluations

Benign Paroxysmal Positional Vertigo (BPPV)

• Evaluate with Dix-Hallpike maneuver
• Positive test: vertigo and characteristic nystagmus 1, 2

Vestibular Neuritis/Labyrinthitis

• Acute onset, persistent vertigo
• Normal HINTS examination (positive head impulse test, direction-fixed nystagmus, no skew deviation) 1

Menière's Disease

• Evaluate for episodic vertigo with fluctuating hearing loss, tinnitus, and aural fullness 1

Vestibular Migraine

• History of migraine headaches
• Episodes of variable duration
• May have light sensitivity and motion intolerance 1

Central Causes (Stroke/TIA)

• Abnormal HINTS examination (normal head impulse test, direction-changing nystagmus, or skew deviation)
• Associated neurological symptoms
• Risk factors for cerebrovascular disease 1

Red Flags Requiring Urgent Evaluation

• Abnormal HINTS examination suggesting central cause
• Neurological deficits accompanying dizziness
• Sudden, severe headache with dizziness
• High vascular risk profile with acute vestibular symptoms
• Ataxia symptoms
• History of previous stroke or diabetes mellitus 1

Common Pitfalls to Avoid

• Relying solely on symptom quality rather than timing and triggers
• Overreliance on CT imaging for posterior fossa evaluation
• Missing stroke in isolated AVS (occurs in 11% of patients with acute persistent vertigo)
• Overuse of vestibular suppressants delaying central compensation
• Failure to perform orthostatic vital signs
• Incomplete neurological examination 1

The diagnostic approach to dizziness has evolved from the traditional symptom-based categorization to a more timing and trigger-focused approach, which has proven more reliable for accurate diagnosis 1, 2, 3. By following this systematic approach, clinicians can efficiently identify the cause of dizziness and initiate appropriate management to improve morbidity, mortality, and quality of life outcomes.