What is the recommended approach for evaluating dizziness in an outpatient setting?

Evaluation of Dizziness in the Outpatient Setting

The evaluation of dizziness should begin by categorizing the symptom based on timing and triggers into one of four vestibular syndromes—acute vestibular syndrome, triggered episodic, spontaneous episodic, or chronic vestibular syndrome—rather than relying on vague patient descriptions, as this classification directly guides diagnostic testing and management decisions. 1, 2

Initial Clinical Assessment

History Taking Priority

• Focus on specific timing characteristics: Determine if symptoms last seconds (suggesting BPPV), minutes to hours (suggesting vestibular migraine or Ménière's), or days to weeks (suggesting vestibular neuritis or stroke) 3, 1
• Identify specific triggers: Head position changes strongly suggest BPPV, while spontaneous episodes without triggers raise concern for Ménière's disease or vestibular migraine 1, 2
• Screen for red flag symptoms: New severe headache, focal neurological deficits (diplopia, dysarthria, facial numbness, limb weakness), sudden unilateral hearing loss, inability to stand independently, or loss of consciousness all mandate urgent evaluation 4, 2
• Assess associated symptoms: Hearing loss, tinnitus, or aural fullness suggest Ménière's disease; headache with photophobia/phonophobia suggests vestibular migraine 3, 1
• Review medications systematically: Antihypertensives, sedatives, anticonvulsants, and psychotropic drugs are leading causes of chronic dizziness 1

Physical Examination Components

• Observe for spontaneous nystagmus in primary gaze and with gaze holding 1, 2
• Perform Dix-Hallpike maneuver for all patients with brief episodic symptoms triggered by position changes to diagnose posterior canal BPPV 3, 2
• Conduct supine roll test to evaluate for horizontal canal BPPV 1, 2
• Execute HINTS examination (Head Impulse, Nystagmus, Test of Skew) in patients with acute persistent vertigo, as this has 100% sensitivity for stroke when performed by trained practitioners, exceeding early MRI sensitivity of 46% 1
• Check orthostatic vital signs to identify presyncope from autonomic dysfunction 3

Imaging Decision Algorithm

When Imaging is NOT Indicated

• Brief episodic vertigo with typical BPPV features on Dix-Hallpike testing requires no imaging 3, 1
• Acute persistent vertigo with normal neurologic exam and HINTS examination consistent with peripheral vertigo (when performed by trained examiner) 3, 1
• Isolated dizziness without red flags has extremely low imaging yield (<1% for CT, ~4% for MRI) and most findings are incidental 3, 4

When MRI Brain Without Contrast is Indicated

• Acute persistent vertigo with abnormal neurologic examination 3, 1
• HINTS examination suggesting central cause (normal head impulse test, direction-changing nystagmus, or skew deviation) 1, 4
• High vascular risk patients with acute vestibular syndrome even with reassuring bedside examination 4
• Unilateral or pulsatile tinnitus to exclude cerebellopontine angle tumors or vascular malformations 4
• Progressive symptoms suggesting mass lesion 1
• Downbeating nystagmus or other central nystagmus patterns 4

CT Head Limitations

• CT has only 20-40% sensitivity for detecting causative pathology in dizziness and particularly misses posterior circulation infarcts 3, 4
• CT may be used initially in acute settings when immediate stroke evaluation is needed before MRI availability, but should not replace MRI for definitive evaluation 3

Diagnostic Testing Beyond Imaging

Audiometric Testing

• Obtain formal audiogram for patients with suspected Ménière's disease, unilateral tinnitus, or asymmetric hearing symptoms, as hearing loss is a necessary criterion for definitive Ménière's diagnosis 3
• Include pure tone thresholds and speech recognition testing to quantify any conductive component 3

When Additional Testing is NOT Needed

• Routine vestibular testing is not indicated for straightforward BPPV diagnosed by Dix-Hallpike maneuver 3
• Radiographic imaging should not be obtained unless the diagnosis is uncertain or additional neurological symptoms atypical for BPPV are present 3

Management Based on Diagnosis

Benign Paroxysmal Positional Vertigo

• Treat with canalith repositioning procedures (Epley maneuver) as first-line therapy without need for imaging or medication in typical cases 1, 4
• Posttraumatic BPPV may require repeated treatments (up to 67% of cases versus 14% for non-traumatic forms) 3

Vestibular Migraine

• Consider this diagnosis when headache, photophobia, and phonophobia accompany vestibular symptoms 3
• Recognize high prevalence: 35% of Ménière's patients also meet criteria for vestibular migraine 3
• Initiate migraine prophylaxis and lifestyle modifications 1

Ménière's Disease

• Manage with salt restriction and diuretics as initial therapy 1
• Consider intratympanic treatments for refractory cases 1

Critical Pitfalls to Avoid

• Do not rely on patient descriptions of "spinning" versus "lightheadedness": These subjective terms are unreliable; instead categorize by timing and triggers 1, 4
• Do not assume normal neurologic exam excludes stroke: 75-80% of patients with acute vestibular syndrome from posterior circulation infarction have no focal neurologic deficits on standard examination 1, 4
• Do not use CT instead of MRI when stroke is suspected: CT misses many posterior circulation infarcts that cause dizziness 3, 4
• Do not order routine imaging for isolated dizziness: The diagnostic yield is extremely low and bedside testing (Dix-Hallpike, HINTS) provides more diagnostic value in most cases 4, 2
• Do not miss the opportunity to perform bedside vestibular testing: These maneuvers are more diagnostically valuable than imaging for common peripheral causes 4

Disposition Considerations

• Manage typical BPPV and presumptive reflex-mediated syncope in outpatient setting in absence of serious medical conditions 3
• Consider home safety assessment for patients with recurrent falls or those requiring supervision, particularly elderly patients with comorbidities 3
• Recognize quality of life impact: BPPV significantly affects multiple quality-of-life domains, and some patients may need temporary additional support 3