What is the appropriate initial evaluation and management for a patient presenting with dizziness and diplopia?

Evaluation and Management of Dizziness with Diplopia

Immediate Assessment: Rule Out Life-Threatening Causes

Any patient presenting with dizziness and diplopia requires urgent evaluation for posterior fossa pathology (brainstem or cerebellar stroke) and aneurysm, as this combination suggests involvement of vestibular pathways and cranial nerves, which can be life-threatening. 1

Critical Red Flags Requiring Emergency Neuroimaging

• Pupil-involving third nerve palsy (anisocoria with ptosis and ophthalmoplegia) mandates immediate MRA or CTA to exclude posterior communicating artery aneurysm—a neurosurgical emergency. 2, 1
• Associated neurological symptoms including ataxia, hemiparesis, sensory loss, Horner's syndrome, or internuclear ophthalmoplegia indicate brainstem or cerebellar pathology requiring urgent imaging. 1
• Multiple ipsilateral cranial nerve palsies (III, IV, VI) suggest cavernous sinus or orbital apex pathology. 2
• Vomiting with diplopia suggests posterior fossa involvement, particularly vestibular pathways in the brainstem or cerebellum. 1

Systematic History Taking

Diplopia Characteristics

• Onset pattern: Sudden onset suggests vascular (stroke, aneurysm) or traumatic causes; gradual onset suggests compressive lesions or thyroid eye disease. 2
• Trauma history: Even occult orbital fractures can present with strabismus without recalled trauma. 2
• Associated symptoms to probe for:
  • Ptosis suggests third nerve involvement 2
  • Facial numbness suggests cavernous sinus pathology 2
  • Vision loss suggests concurrent optic neuropathy 2

Dizziness Characteristics

• Timing and triggers: Determine if dizziness is episodic (triggered by position changes suggesting benign paroxysmal positional vertigo) versus constant (suggesting central pathology or vestibular neuritis). 3, 4
• Quality of dizziness: Vertigo (spinning/whirling sensation) suggests vestibular causes; presyncope (near-fainting) suggests cardiovascular causes; disequilibrium (imbalance) suggests sensory/motor pathway dysfunction; vague lightheadedness suggests psychiatric or metabolic causes. 3

Focused Physical Examination

Ocular Examination

• Visual acuity and refraction: Document baseline vision; high hyperopia or anisometropia may contribute to decompensated strabismus. 2
• Pupillary examination: Assess for anisocoria (third nerve palsy), relative afferent pupillary defect (optic neuropathy), and accommodation deficit. 2
• Extraocular motility testing: Evaluate versions (both eyes together), ductions (each eye separately), saccades, smooth pursuit, vergence, and near reflex. 2
• Assessment for nystagmus: Presence and direction help localize vestibular versus central pathology. 3, 4

Vestibular Examination

• Dix-Hallpike maneuver: Perform in patients with triggered episodic dizziness to diagnose benign paroxysmal positional vertigo. 3, 4
• HINTS examination (head-impulse, nystagmus, test of skew): Use when acute vestibular syndrome is suspected to differentiate peripheral from central causes. 4

Cardiovascular Examination

• Orthostatic blood pressure testing: Measure supine and standing blood pressures to identify orthostatic hypotension causing presyncope. 3, 4

Neuroimaging Strategy

Brain MRI with and without gadolinium plus MRA or CTA is the preferred initial study for all patients with diplopia and dizziness, especially when cranial nerve palsies are present. 2, 1

• If pupil-involving third nerve palsy is present and initial MRA/CTA is negative but suspicion remains high, proceed to catheter angiography after brain MRI with contrast. 2, 1
• Unenhanced CT of the head or orbits is not useful in the workup of diplopia. 2
• Isolated sixth nerve palsy requires evaluation for increased intracranial pressure. 2

Differential Diagnosis by Pattern

Peripheral Vestibular Causes (with secondary diplopia from nystagmus or decompensation)

• Benign paroxysmal positional vertigo: Episodic vertigo triggered by head position changes; diagnosed with Dix-Hallpike maneuver. 3, 4
• Vestibular neuritis: Acute onset severe vertigo with nausea/vomiting, self-limiting; may respond to steroids. 1, 3
• Meniere disease: Episodic vertigo with hearing loss and tinnitus. 3

Central Causes (diplopia with dizziness)

• Brainstem or cerebellar stroke: Transient ischemia may cause transient skew deviation; more profound ischemic damage causes persistent symptoms. 1
• Posterior communicating artery aneurysm: Most concerning with pupil-involving third nerve palsy. 2, 1
• Microvascular ischemic cranial nerve palsies: Associated with diabetes, hypertension, hyperlipidemia; typically resolve within 6 months. 1

Other Causes

• Giant cell arteritis: Requires immediate high-dose corticosteroids to prevent permanent vision loss. 1
• Cavernous sinus pathology: Multiple ipsilateral cranial nerve palsies with facial numbness. 2

Initial Management

Symptomatic Relief for Diplopia

• Occlusion: Eye patch, occlusive contact lens, or Bangerter foil provides immediate relief while awaiting diagnosis. 2, 1
• Prism correction: Press-on (Fresnel) or ground-in prisms can provide temporary relief, though effectiveness is limited in incomitant deviations. 2

Symptomatic Relief for Vestibular Dizziness

• Meclizine 25-100 mg daily orally in divided doses is indicated for treatment of vertigo associated with vestibular system diseases in adults. 5
• Caution: Meclizine causes drowsiness; patients should avoid driving and alcohol. Use with caution in patients with asthma, glaucoma, or prostate enlargement. 5
• Vestibular rehabilitation: Initiate as soon as possible after injury to ensure best compensation. 6, 4

Specific Treatments Based on Etiology

• Benign paroxysmal positional vertigo: Epley maneuver (canalith repositioning) is the most effective treatment. 3, 4
• Microvascular ischemic palsies: Optimize diabetes, hypertension, hyperlipidemia management; typically resolve within 6 months. 1
• Aneurysm: Requires urgent neurosurgical consultation. 2, 1

Disposition and Referral

Immediate Ophthalmology/Neurosurgery Consultation Required

• Pupil-involving third nerve palsy 2, 1
• Signs of increased intracranial pressure 2, 1
• Multiple cranial nerve palsies 2
• Associated neurological deficits (ataxia, hemiparesis, sensory loss) 1

Follow-Up Protocol

• Reassess at 6 months: If no recovery by 6 months in microvascular ischemic palsies, further evaluation for underlying pathology is warranted. 1
• Control vascular risk factors: Optimize diabetes, hypertension, hyperlipidemia management. 1

Common Pitfalls to Avoid

• Do not discharge isolated sixth nerve palsy without considering increased intracranial pressure, as it may occur with elevated ICP without direct nerve compression. 2
• Do not miss bilateral cranial nerve involvement, which suggests more extensive pathology. 2
• Do not attribute symptoms to benign causes without excluding serious pathology through appropriate history, examination, and imaging. 2, 1
• Transient diplopia after strabismus surgery is common, but persistent diplopia after successful surgery occurs in 1% or fewer patients. 7