What is the appropriate management for an adult patient with no significant past medical history presenting with vomiting and diplopia?

Urgent Neurological Evaluation Required for Vomiting with Diplopia

An adult presenting with vomiting and diplopia requires urgent neuroimaging with brain MRI with and without gadolinium plus MRA or CTA to exclude life-threatening posterior fossa pathology, including brainstem stroke, cerebellar lesions, aneurysm, or mass lesions. 1

Immediate Diagnostic Approach

Critical Red Flags Requiring Same-Day Imaging

• Vomiting with diplopia suggests posterior fossa involvement, particularly vestibular pathways in the brainstem or cerebellum, which can present with severe vertigo, dizziness, nausea, and vomiting alongside diplopia 1
• Pupil involvement mandates emergent evaluation for posterior communicating artery aneurysm, requiring CT/CTA of the brain immediately 1
• Associated neurological symptoms including ataxia, hemiparesis, sensory loss, Horner's syndrome, or internuclear ophthalmoplegia indicate brainstem or cerebellar pathology requiring urgent imaging 1

Specific Examination Elements to Document

• Pupillary function: Pupil-sparing versus pupil-involving third nerve palsy fundamentally changes urgency and differential 1
• Pattern of diplopia: Vertical diplopia with head tilt suggests skew deviation from vestibular pathway involvement 1
• Associated vestibular signs: Severe vertigo, nystagmus, and vomiting point toward acute peripheral vestibulopathy or central vestibular pathology 1
• Oculocardiac reflex: Bradycardia or heart block with diplopia, nausea, and vomiting in trauma suggests entrapped extraocular muscle requiring urgent surgical intervention 1
• Fundoscopy: Check for papilledema (mass effect) or optic atrophy 1
• Other cranial nerve deficits: Facial nerve palsy, hearing loss, or multiple cranial neuropathies broaden the differential 1

Imaging Protocol

First-Line Imaging

• Brain MRI with and without gadolinium contrast plus MRA or CTA is the preferred initial study for acute diplopia with neurological symptoms 1, 2, 3
• Plain CT head is largely not useful in the workup of diplopia unless trauma or acute hemorrhage is suspected 3

When to Escalate Imaging

• Catheter angiography should be considered if high suspicion for aneurysm persists despite normal MRA/CTA, particularly with pupil-involving third nerve palsy 1
• CT with CTA is acceptable if MRI is contraindicated or unavailable, especially for suspected aneurysm 1, 3

Differential Diagnosis by Pattern

Skew Deviation (Vertical Diplopia + Vomiting)

• Acute vestibular neuronitis: Self-limiting, presents with severe vertigo, nausea, vomiting, and may respond to medical intervention 1
• Brainstem or cerebellar stroke: Transient ischemia may cause transient skew deviation; more profound ischemic damage causes persistent symptoms 1
• Demyelinating disease: More insidious onset if due to demyelination or slow-growing tumor 1
• Mass lesions: Tumors affecting vestibular supranuclear pathways 1

Third Nerve Palsy with Systemic Symptoms

• Posterior communicating artery aneurysm: Most concerning with pupil involvement 1
• Pituitary pathology: Pituitary abscess or apoplexy can present with headache, vomiting, diplopia, and ophthalmoplegia 4, 5
• Cavernous sinus pathology: Consider CT venogram if cavernous sinus thrombosis suspected 3

Post-Infectious/Para-Infectious

• Bacterial meningitis complications: Can cause cranial nerve palsies with fever, headache, nausea, and vomiting 6
• Post-viral cranial neuropathy: Typically isolated sixth nerve palsy, but requires exclusion of serious pathology first 2

Age-Specific Considerations

Patients Over 60 Years

• Giant cell arteritis must be excluded in elderly patients with diplopia, particularly if accompanied by headache, scalp tenderness, temporal pain, or jaw claudication 2, 3
• Obtain inflammatory markers (ESR, CRP) urgently in patients over 60 with recent-onset diplopia 3

Younger Patients

• Demyelinating disease (multiple sclerosis) more likely in younger adults with brainstem involvement 1, 2

Management Based on Etiology

Vascular Causes

• Microvascular ischemic palsies (diabetes, hypertension, hyperlipidemia) typically resolve within 6 months and can be observed if imaging excludes compressive lesions 1, 2, 7
• Acute stroke: Consider thrombolytic therapy if within appropriate time window 8

Compressive Lesions

• Aneurysm: Requires urgent neurosurgical consultation 1
• Tumors: Surgical resection may be indicated depending on type, location, and patient factors 8
• Pituitary abscess: Requires transphenoidal surgery with antibiotic therapy 5

Inflammatory/Infectious

• Bacterial meningitis: Ceftriaxone antibiotic therapy; consider steroids for para-infectious cranial neuropathy 6
• Giant cell arteritis: High-dose corticosteroids immediately to prevent permanent vision loss 2

Symptomatic Management of Diplopia

Acute Phase

• Eye patching or occlusion for immediate relief while awaiting diagnosis 1, 2
• Prisms are not helpful for homonymous field defects but may help with cranial nerve palsies 1, 8

Subacute Management (Awaiting Recovery)

• Botulinum toxin injection to antagonist muscles can temporize while waiting for recovery 1, 2
• Press-on or ground-in prisms may be helpful following partial recovery 1

Surgical Intervention

• Consider strabismus surgery after 6-12 months if no further recovery expected 1, 2

Follow-Up Protocol

If Microvascular Etiology Confirmed

• Reassess at 6 months: If no recovery by 6 months, further evaluation for underlying pathology is warranted 2, 7
• Control vascular risk factors: Optimize diabetes, hypertension, hyperlipidemia management 1

If Serious Pathology Excluded

• Referral to neurology or ophthalmology for outpatient workup of isolated fourth or sixth nerve palsies without other neurological signs 3