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

Diagnostic Workup for Dizziness

The initial diagnostic 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 a 12-lead ECG. 1

Initial Evaluation

History: Focus on Timing and Triggers

• Categorize dizziness into one of three patterns:
  1. Acute Vestibular Syndrome (continuous dizziness lasting days)
  2. Spontaneous Episodic Vestibular Syndrome (recurrent episodes without triggers)
  3. Triggered Episodic Vestibular Syndrome (episodes provoked by specific movements) 1, 2

Physical Examination

• Vital signs with orthostatic blood pressure measurements 3, 1
• Cardiovascular exam including heart sounds and rhythm
• Neurological assessment including cranial nerves, coordination, and gait
• Vestibular examination:
  • HINTS test (Head-Impulse, Nystagmus, Test of Skew) for acute vestibular syndrome to differentiate peripheral from central causes 1, 4
  • Dix-Hallpike maneuver for suspected BPPV 1, 5
  • Supine roll test for horizontal canal BPPV 2

Basic Testing

• 12-lead ECG to evaluate for arrhythmias 3, 1
• Laboratory tests (based on clinical suspicion, not routinely):
  • Blood glucose
  • Complete blood count
  • Electrolytes
  • Toxicology screening when indicated 1

Diagnostic Algorithm Based on Pattern

1. Acute Vestibular Syndrome

• Perform HINTS examination:
  • Abnormal HINTS (normal head impulse, direction-changing nystagmus, or skew deviation) → Brain MRI without contrast to rule out stroke 1, 4
  • Normal HINTS (abnormal head impulse, unidirectional nystagmus, no skew) → Likely peripheral cause (vestibular neuritis) 1, 2

2. Spontaneous Episodic Vestibular Syndrome

• Evaluate for associated symptoms:
  • With headache, photophobia → Consider vestibular migraine
  • With vascular risk factors → Consider TIA, obtain MRI if high suspicion 1, 5
  • With hearing loss, tinnitus, aural fullness → Consider Menière's disease 1

3. Triggered Episodic Vestibular Syndrome

• Perform Dix-Hallpike and supine roll tests:
  • Positive with characteristic nystagmus → BPPV (treat with canalith repositioning) 1, 5
  • Negative or atypical response → Consider central causes, obtain MRI 1, 2

Indications for Neuroimaging (MRI Brain)

• Acute vestibular syndrome with abnormal HINTS examination
• Neurological deficits
• High vascular risk patients with acute vestibular syndrome
• Chronic undiagnosed dizziness not responding to treatment 1

Common Pitfalls and Caveats

• Avoid overreliance on symptom quality (vertigo vs. lightheadedness) as it doesn't reliably distinguish serious from benign causes 2, 5
• Don't miss posterior circulation strokes which can present with isolated dizziness, especially in elderly patients or those with vascular risk factors 1, 4
• Avoid routine neuroimaging for typical BPPV, as it has low diagnostic yield 1
• Remember common causes - the five most frequent categories are vasovagal syncope/orthostatic hypotension (22.3%), vestibular causes (19.9%), fluid/electrolyte disorders (17.5%), circulatory/pulmonary causes (14.8%), and central vascular causes (6.4%) 4
• Consider high-risk patients - those with anemia, stroke, or diabetes represent a high-risk group (50%) for poor outcomes 6

The diagnostic approach outlined above follows current best evidence and offers the potential to reduce misdiagnosis while simultaneously decreasing diagnostic test overuse and unnecessary hospitalizations 2.