What is the appropriate diagnostic approach for a patient presenting with dizziness, considering their unique medical history and potential risk factors for cardiovascular disease?

Diagnostic Approach to Dizziness

The diagnosis of dizziness begins by categorizing the patient into one of four temporal patterns—brief episodic vertigo (seconds to minutes), acute persistent vertigo (days to weeks), spontaneous episodic vertigo, or chronic vestibular syndrome—based on timing and specific triggers rather than the patient's vague description of "dizziness." 1, 2

Initial Clinical Assessment

Critical History Elements

The most diagnostically valuable information comes from precise timing and triggers, not whether patients describe "spinning" versus "lightheadedness" 2, 3:

• Duration of episodes: Seconds suggest BPPV, minutes to hours suggest vestibular migraine or Ménière's disease, days to weeks suggest vestibular neuritis or stroke 1, 2
• Specific triggers: Head position changes (BPPV), prolonged standing (orthostatic hypotension), exercise (cardiac arrhythmia) 2, 4
• Associated symptoms:
  • Hearing loss, tinnitus, or aural fullness strongly suggest peripheral vestibular pathology (Ménière's disease) 2, 5
  • Headache, photophobia, phonophobia indicate vestibular migraine 1, 2
  • Syncope, need to sit/lie down, pallor predict cardiovascular causes 4
  • Focal neurologic symptoms (dysarthria, diplopia, weakness) are red flags for central pathology 2, 3

Cardiovascular Risk Assessment

For patients with cardiovascular risk factors or concerning features, specific historical elements predict cardiac etiology 4:

• Dizziness described as "lightheadedness" with need to sit or lie down during symptoms (P < .001) 4
• Pallor accompanying symptoms (P < .001) 4
• Precipitation by prolonged standing (P < .05) 4
• Coexisting cardiovascular disease (P < .05) 4
• Presence of syncope or falls in addition to dizziness (46% of geriatric patients) 4

Physical Examination

Essential Bedside Tests

The Dix-Hallpike maneuver is mandatory for any patient with brief episodic dizziness triggered by position changes, as it is the gold standard for diagnosing BPPV with 90-98% diagnostic accuracy 2, 3. Positive findings include:

• Latency period of 5-20 seconds before symptoms begin 2, 3
• Torsional, upbeating nystagmus toward the affected ear 2, 3
• Vertigo and nystagmus that increase then resolve within 60 seconds 2, 3

For acute persistent vertigo, the HINTS examination (Head-Impulse, Nystagmus, Test of Skew) has 100% sensitivity for detecting posterior circulation stroke when performed by trained practitioners, compared to only 46% sensitivity for early MRI 2. However, when performed by non-experts, reliability decreases significantly 1, 2.

Nystagmus Patterns

• Horizontal or horizontal-rotatory nystagmus suggests peripheral cause 5
• Pure vertical or direction-changing nystagmus strongly indicates central pathology 2, 5
• Downbeating nystagmus is a red flag requiring urgent evaluation 2, 3

Neurologic Examination

Perform comprehensive cranial nerve testing, cerebellar testing (finger-to-nose, heel-to-shin, rapid alternating movements), gait assessment, and Romberg testing 3. Critical pitfall: 75-80% of patients with acute vestibular syndrome from posterior circulation infarction have NO focal neurologic deficits, so a normal neurologic exam does not exclude stroke 2, 5.

Imaging Decisions

When Imaging Is NOT Indicated

No imaging is needed for 1, 2:

• Brief episodic vertigo with typical BPPV features on Dix-Hallpike testing 1, 2
• Acute persistent vertigo with normal neurologic exam AND HINTS examination consistent with peripheral vertigo by a trained examiner 2
• Straightforward BPPV meeting diagnostic criteria—ordering imaging only delays treatment 3

When MRI Brain Without Contrast Is Indicated

MRI brain without contrast (NOT CT) should be obtained for 1, 2, 3:

• Acute persistent vertigo with abnormal neurologic examination 2
• HINTS examination suggesting central cause (absent head impulse test, direction-changing nystagmus, vertical skew deviation) 2, 5
• High vascular risk patients with acute vestibular syndrome 2
• Focal neurological deficits 2, 3
• Sudden unilateral hearing loss 3
• Inability to stand or walk 2, 3
• New severe headache accompanying dizziness 2, 3
• Progressive neurologic symptoms suggesting mass lesion 2
• Unilateral or pulsatile tinnitus 2
• Asymmetric hearing loss 2

CT Head Limitations

CT head has extremely poor diagnostic yield for dizziness with sensitivity of only 20-40% for detecting causative pathology, particularly posterior circulation infarcts 1, 2. CT may be appropriate before MRI in acute settings when stroke is suspected, but should not replace MRI 1, 2. Routine CT for isolated dizziness has <1% diagnostic yield 1.

CTA Head and Neck

CTA is NOT routinely indicated for isolated dizziness, with only 3% diagnostic yield, 14% sensitivity, and no additional information beyond non-contrast CT 2. CTA may be appropriate specifically for pulsatile tinnitus to evaluate vascular malformations, arterial dissection, or aberrant vascular anatomy 2.

Cardiovascular Workup

For patients with presyncope/syncope features or cardiovascular risk factors 1, 4:

• 12-lead ECG is mandatory to evaluate for conduction abnormalities, long QT syndrome, or other arrhythmogenic conditions 1
• Orthostatic vital signs (blood pressure and heart rate supine, then after 1 and 3 minutes standing) to detect orthostatic hypotension 1, 4
• Echocardiography if structural heart disease suspected based on history, exam, or ECG 1
• Ambulatory ECG monitoring (24-48 hour Holter if daily symptoms; implantable loop recorder if episodes occur every few weeks) if cardiac arrhythmia suspected 1
• Tilt-table testing is NOT first-line and should be reserved for suspected vasovagal syncope with recurrent unexplained episodes 1

Urgent specialist cardiovascular assessment is required for 1:

• Severe bradycardia or atrioventricular block 1
• Suspected inherited cardiac conditions (long QT syndrome) 1
• TLoC during exercise 1
• History or signs of heart failure 1
• ECG abnormalities suggesting arrhythmia 1

Red Flags Requiring Urgent Evaluation

Immediate imaging and neurologic consultation are mandatory for 2, 3:

• Focal neurological deficits (dysarthria, diplopia, numbness, weakness) 2, 3
• Sudden unilateral hearing loss 2, 3
• Inability to stand or walk 2, 3
• Downbeating or other central nystagmus patterns 2, 3
• New severe headache accompanying dizziness 2, 3
• Failure to respond to appropriate vestibular treatments 2

Common Diagnostic Pitfalls

Avoid these critical errors 1, 2, 3:

• Relying on patient's description of "spinning" versus "lightheadedness" instead of focusing on timing and triggers 2, 3
• Assuming normal neurologic exam excludes stroke (75-80% of posterior circulation strokes have no focal deficits) 2, 5
• Ordering imaging for straightforward BPPV, which delays treatment unnecessarily 3
• Skipping the Dix-Hallpike maneuver 3
• Using CT instead of MRI when stroke is suspected (CT misses most posterior circulation infarcts) 1, 2
• Overlooking vestibular migraine, which is extremely common but under-recognized 3
• Ordering routine laboratory tests, which have low yield in unselected patients 6
• Requesting electroencephalography for brief seizure activity during syncope, which does not require neurologic investigation 1

Medication Review

Medication side effects are a leading reversible cause of chronic dizziness, particularly with antihypertensives, sedatives, anticonvulsants, and psychotropic drugs 2, 3. A comprehensive medication review is essential and may identify the cause without further testing 2, 3.

Psychiatric Screening

Anxiety, panic disorder, and depression are common causes of chronic dizziness (10-25% of patients) and should be systematically screened 2, 6, 7. The adjusted relative risk for dizziness is 1.69 for anxiety and 1.36 for depressive symptoms 7.