What is the initial approach to a workup for an adult patient presenting with dizziness and no significant past medical history?

Initial Workup for Adult Patient with Acute Dizziness

Classify the dizziness by timing and triggers—not by the patient's vague description of "spinning" or "lightheadedness"—then perform targeted physical examination maneuvers to distinguish benign peripheral causes from dangerous central pathology. 1, 2, 3

Step 1: Temporal Classification (Most Critical Diagnostic Step)

Immediately categorize into one of four vestibular syndromes based on duration and triggers 1, 3:

• Triggered episodic vertigo (seconds to <1 minute): Brief episodes provoked by specific head position changes suggest BPPV (42% of all vertigo cases), superior canal dehiscence, or perilymphatic fistula 1, 3

• Spontaneous episodic vertigo (minutes to hours): Unprovoked episodes lasting 20 minutes to hours suggest vestibular migraine (14% of cases, often underdiagnosed), Ménière's disease, or vertebrobasilar insufficiency 1, 3

• Acute vestibular syndrome (days): Continuous severe vertigo lasting days suggests vestibular neuritis (41% of peripheral vertigo), labyrinthitis, or posterior circulation stroke (25% of acute vestibular syndrome cases) 1, 2, 3

• Chronic vertigo (weeks to months): Persistent symptoms suggest medication effects (leading reversible cause), anxiety disorder, or posterior fossa mass 1, 3

Step 2: Targeted History Elements

After temporal classification, probe for these specific features 1, 2, 3:

• Auditory symptoms: Hearing loss, tinnitus, or aural fullness point to Ménière's disease (fluctuating hearing loss) versus vestibular migraine (stable/absent hearing loss) 1, 2

• Migrainous features: Headache, photophobia, phonophobia strongly suggest vestibular migraine—ask about current or past migraine history and family history 1, 2

• Vascular risk factors: Age >50, hypertension, diabetes, atrial fibrillation, or prior stroke dramatically increase stroke risk 1, 2, 3

• Medication review: Antihypertensives, sedatives, anticonvulsants, and psychotropic drugs are the most common reversible cause of chronic dizziness 1, 3

Step 3: Physical Examination Protocol

For Triggered Episodic Vertigo (Suspected BPPV):

• Perform Dix-Hallpike maneuver bilaterally as the gold standard diagnostic test 1, 3
• Diagnostic criteria: 5-20 second latency, torsional upbeating nystagmus toward affected ear, symptoms that crescendo then resolve within 60 seconds 1, 3
• If negative but history compatible, perform Supine Roll Test for lateral canal BPPV (10-15% of BPPV cases) 1
• Critical pitfall: Do NOT perform Dix-Hallpike if Romberg test is positive—this indicates central pathology requiring imaging first 1

For Acute Vestibular Syndrome:

• Perform HINTS examination (Head Impulse, Nystagmus, Test of Skew) if trained—it has 100% sensitivity for stroke versus only 46% for early MRI 1, 2, 3
• Central cause indicators: normal head impulse test, direction-changing or vertical nystagmus, present skew deviation 1, 2, 3
• Major caveat: HINTS is unreliable when performed by non-experts—if untrained, proceed directly to imaging for high-risk patients 2

Step 4: Red Flags Requiring Urgent MRI

Order MRI brain without and with IV contrast immediately for any of these features 1, 2, 3:

• Focal neurological deficits (though 75-80% of posterior circulation strokes initially lack focal deficits) 1, 2
• Severe postural instability or inability to stand/walk 1, 2
• Downbeating nystagmus or other central nystagmus patterns 1, 2
• Sudden unilateral hearing loss 1, 2
• New severe headache accompanying dizziness 1, 2
• Age >50 with vascular risk factors presenting with acute vestibular syndrome, even with normal neurologic exam (11-25% have posterior circulation stroke) 1, 2
• Positive Romberg test 1
• HINTS examination suggesting central cause 1, 2

Critical point: CT head has <1% diagnostic yield for isolated dizziness and misses most posterior circulation infarcts—never substitute CT for MRI when stroke is suspected 1, 2

Step 5: When NO Imaging is Needed

Skip imaging entirely for 1, 2, 3:

• Brief episodic vertigo with typical BPPV features and positive Dix-Hallpike test 1, 2
• Acute vestibular syndrome with normal neurologic exam AND HINTS consistent with peripheral vertigo by trained examiner 1, 2
• No red flags, no vascular risk factors, and clear peripheral vestibular diagnosis 1, 2

Step 6: Laboratory Testing Strategy

Do NOT order routine blood tests (CBC, CMP) for typical BPPV or peripheral vertigo—the diagnosis is clinical 1, 3:

• Check fingerstick glucose immediately as hypoglycemia is the most frequently identified unexpected abnormality 2
• Order audiometry only when auditory symptoms suggest Ménière's disease or other inner ear pathology 1, 3
• Consider autoimmune panels only for progressive bilateral fluctuating hearing loss potentially steroid-responsive 1
• Order serologic testing (Lyme, syphilis) only for suspected infectious causes with severe otalgia, fever, or sudden bilateral hearing loss 1

Step 7: Initial Management Based on Diagnosis

For Confirmed BPPV:

• Perform canalith repositioning procedures (Epley maneuver) immediately as first-line treatment—80% success after 1-3 treatments, 90-98% with repeat maneuvers 1, 2, 3
• No medications needed for typical BPPV 1, 2
• Counsel about recurrence risk and fall risk (BPPV increases fall risk 12-fold in elderly) 2

For Acute Vestibular Syndrome (Vestibular Neuritis):

• Offer limited course of vestibular suppressants (meclizine) only during acute attacks for symptomatic management 3, 4
• Avoid prolonged vestibular suppressant use as it delays central compensation 3

For Vestibular Migraine:

• Initiate migraine prophylaxis and lifestyle modifications 1, 2

For Ménière's Disease:

• Low-sodium diet, avoid excessive caffeine/alcohol, adequate hydration, stress management 3

Common Diagnostic Pitfalls to Avoid

• Assuming normal neurologic exam excludes stroke: 75-80% of posterior circulation strokes causing vertigo lack focal deficits initially 1, 2
• Relying on patient's description of "spinning": Focus on timing and triggers instead 1, 2, 3
• Misdiagnosing central causes as BPPV: CNS disorders masquerade as BPPV in 3% of treatment failures 1
• Ordering CT instead of MRI: CT misses most posterior fossa strokes 1, 2
• Overlooking medication side effects: Review all medications as this is the leading reversible cause 1, 3
• Missing vestibular migraine: Extremely common (14% of vertigo) but underrecognized, especially in young patients 1, 2