What tests should be ordered for a patient presenting with dizziness, considering their age, medical history, and nature of the dizziness?

Tests for Dizziness

The initial workup for dizziness should be guided by timing and triggers rather than symptom quality, with most patients requiring only targeted bedside examination (Dix-Hallpike maneuver for triggered episodes, HINTS examination for acute persistent vertigo) and no imaging unless red flags are present. 1, 2, 3

Clinical Classification Framework

The first step is categorizing dizziness into one of three vestibular syndromes based on temporal pattern 1, 2, 4:

• Brief episodic vertigo (seconds to <1 minute): Triggered by head position changes, suggests BPPV 5, 3
• Acute persistent vertigo (days to weeks): Constant symptoms, suggests vestibular neuritis or posterior circulation stroke 1, 2
• Spontaneous episodic vertigo (minutes to hours): No positional triggers, suggests Ménière's disease or vestibular migraine 1, 4

Essential History Elements

Focus on specific diagnostic details rather than vague descriptions 1, 3:

• Duration: Seconds (BPPV), minutes to hours (Ménière's, vestibular migraine), days to weeks (vestibular neuritis, stroke) 2
• Triggers: Head position changes (BPPV), pressure changes (superior canal dehiscence), none (vestibular neuritis, stroke) 2
• Associated symptoms: Hearing loss, tinnitus, aural fullness suggest Ménière's disease; headache, photophobia, phonophobia suggest vestibular migraine 5, 2, 3
• Vascular risk factors: Age >50, hypertension, atrial fibrillation, diabetes, prior stroke increase stroke risk 5, 1
• Medication review: Antihypertensives, sedatives, anticonvulsants, psychotropic drugs are leading causes of chronic dizziness 3

Bedside Physical Examination Tests

For Brief Episodic Vertigo (Suspected BPPV)

• Dix-Hallpike maneuver: Gold standard test with diagnostic criteria including 5-20 second latency, torsional upbeating nystagmus toward affected ear, symptoms resolving within 60 seconds 1, 3
• Supine roll test: For horizontal canal BPPV 2, 4
• No imaging or laboratory testing needed if positive with typical features 3

For Acute Persistent Vertigo

• HINTS examination (Head Impulse, Nystagmus, Test of Skew): When performed by trained practitioners, has 100% sensitivity for posterior circulation stroke versus 46% for early MRI 1, 2, 3
• Complete neurologic examination: Including cranial nerves, cerebellar testing, gait assessment 2
• Observe for spontaneous nystagmus: Present in all patients with acute vestibular syndrome 1

Critical caveat: HINTS examination is unreliable when performed by non-experts, and 75-80% of patients with posterior circulation infarct have no focal neurologic deficits 3

Audiologic Testing

Order comprehensive audiologic examination for 5, 3:

• Unilateral tinnitus (especially pulsatile)
• Asymmetric hearing loss
• Persistent symptoms with hearing complaints
• Suspected Ménière's disease (fluctuating hearing loss, aural fullness, tinnitus) 5

Specific tests include:

• Audiogram: Measures hearing from low to high frequency, takes approximately 30 minutes 5
• Video/electronystagmogram: Evaluates vestibular function, takes approximately 1 hour, may cause vertigo and nausea during testing 5
• Electrocochleography: Measures electrical responses of cochlea and auditory nerve, may cause ear discomfort 5

Imaging Studies: When NOT to Order

No imaging is indicated for 5, 2, 3:

• Brief episodic vertigo with typical BPPV features and positive Dix-Hallpike test
• Acute persistent vertigo with normal neurologic examination AND HINTS examination consistent with peripheral vertigo by trained examiner
• Nonspecific dizziness without vertigo, ataxia, or neurologic deficits
• Vestibular migraine with typical features

Common pitfall: CT head has extremely low diagnostic yield (<1%) for isolated dizziness and misses most posterior circulation infarcts 5, 3

Imaging Studies: When TO Order

MRI Brain Without IV Contrast (Preferred Imaging)

Order for 5, 1, 2, 3:

• Abnormal neurologic examination or focal deficits
• HINTS examination suggesting central cause (by trained examiner)
• High vascular risk patients with acute vestibular syndrome (age >50, hypertension, atrial fibrillation, diabetes, prior stroke), even with normal neurologic examination
• Unilateral or pulsatile tinnitus
• Asymmetric hearing loss
• Progressive neurologic symptoms
• Atypical nystagmus patterns or downbeating nystagmus
• Failure to respond to appropriate vestibular treatments

Diagnostic yield: 4% in isolated dizziness, with ischemic stroke being most common finding (70% of positive cases), two-thirds in posterior circulation 5, 1

MRI Head and Internal Auditory Canal With and Without IV Contrast

Order for 5, 3:

• Chronic recurrent vertigo with unilateral hearing loss or tinnitus (suspected Ménière's disease)
• To exclude vestibular schwannoma or other mass lesions

CT Head Without IV Contrast

May be appropriate 5:

• As initial imaging before MRI in acute settings when stroke suspected
• When MRI is contraindicated or unavailable

Limitations: Detects acute brain lesions in only 6% of cases with atypical vertigo versus 11% with MRI, sensitivity only 20-40% for causative pathology 5

CT Temporal Bone Without IV Contrast

Order for 5:

• Suspected superior semicircular canal dehiscence
• Structural abnormalities of the ear

CTA or MRA Head and Neck

Order for 5:

• Pulsatile tinnitus (evaluate for vascular malformations, arterial dissection)
• Chronic recurrent vertigo with brainstem neurologic deficits (suspected vertebrobasilar insufficiency)

Do NOT routinely order: CTA has only 14% sensitivity and 3% diagnostic yield for isolated dizziness 3

Laboratory Testing

Generally not indicated for most cases of dizziness 6, 7. Consider only when specific conditions suspected based on history and examination.

Red Flags Requiring Urgent Evaluation

Immediate imaging and neurologic consultation needed for 1, 2, 3:

• Focal neurological deficits
• Sudden hearing loss
• Inability to stand or walk
• New severe headache accompanying dizziness
• Downbeating nystagmus or other central nystagmus patterns
• Failure to respond to appropriate vestibular treatments

Critical Pitfalls to Avoid

• Do not rely on patient's description of "spinning" versus "lightheadedness" – focus on timing and triggers instead 3
• Do not assume normal neurologic exam excludes stroke – 75-80% of posterior circulation infarcts have no focal deficits 3
• Do not order CT when stroke is suspected – use MRI with diffusion-weighted imaging 5, 3
• Do not order imaging for straightforward BPPV with positive Dix-Hallpike and no red flags 3
• Do not order comprehensive vestibular testing for typical BPPV – it delays treatment unnecessarily 3