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

Initial Diagnostic Workup for Dizziness

The initial diagnostic workup for dizziness should focus on categorizing the dizziness into one of four vestibular syndromes based on timing and triggers rather than subjective descriptions, which will guide further evaluation and management. 1, 2

Classification of Dizziness

• Categorize dizziness into one of four syndromes: Acute Vestibular Syndrome (AVS), Triggered Episodic Vestibular Syndrome, Spontaneous Episodic Vestibular Syndrome, and Chronic Vestibular Syndrome 1, 2
• Determine if the patient is experiencing true vertigo (rotation/spinning sensation) versus non-specific dizziness (disturbed spatial orientation) 2
• Focus on timing patterns: brief episodes (seconds) suggest BPPV; longer episodes (minutes to hours) suggest Ménière's disease or vestibular migraine 2

Key History Elements

• Assess duration and onset of symptoms 1
• Identify specific triggers such as positional changes (suggesting BPPV) 1, 2
• Document associated symptoms:
  • Hearing loss, tinnitus, or aural fullness (suggesting Ménière's disease) 1, 3
  • Neurological symptoms (headache, diplopia, dysarthria, numbness, weakness) may indicate central causes 1, 3

Physical Examination

• Observe for spontaneous nystagmus in all patients 1, 3
• Perform Dix-Hallpike maneuver and supine roll test to assess for posterior and horizontal canal BPPV 1, 2
• For acute persistent vertigo, perform HINTS examination (Head-Impulse, Nystagmus, Test of Skew) to differentiate peripheral from central causes 4
• Complete neurological examination to identify focal deficits 2, 5
• Measure orthostatic blood pressure to assess for orthostatic hypotension 6, 5

Laboratory Testing

• Laboratory tests are generally not required in the initial workup unless specific conditions are suspected 2, 5
• Consider basic metabolic panel, complete blood count, and thyroid function tests if dehydration, electrolyte abnormalities, infection, or thyroid disorder is suspected 2

Imaging Studies

• Imaging is not routinely indicated for most cases of dizziness, particularly with clear peripheral causes 1, 4
• MRI is preferred over CT for suspected stroke and should be considered when:
  • Neurological symptoms or signs are present 1, 4
  • HINTS examination suggests a central cause 4, 1
  • Patient has abnormal neurologic examination 4
• In BPPV with typical nystagmus on Dix-Hallpike testing, imaging is unnecessary 4

Red Flags Requiring Urgent Evaluation

• Focal neurological deficits 2, 3
• Sudden hearing loss 3
• Inability to stand or walk 2, 3
• Abnormal HINTS examination suggesting central cause 4, 1
• Downbeating nystagmus or other central nystagmus patterns 3

Common Pitfalls to Avoid

• Relying solely on the patient's description of "dizziness" without clarifying the exact nature of symptoms 1, 3
• Failing to perform appropriate bedside tests like the Dix-Hallpike maneuver or HINTS examination 1, 7
• Overuse of imaging in patients with clear peripheral causes of dizziness 1, 4
• Missing stroke in patients with isolated dizziness (approximately 4% of isolated dizziness cases are due to stroke) 1, 8
• Assuming absence of focal neurologic deficits rules out central causes (up to 20% of patients with posterior circulation infarcts have no associated focal deficits) 4, 9