What is the best management approach for a 12-year-old patient with sudden onset diplopia, headache, and initial vomiting, now resolved, with normal MRI, MRA, and MRV results?

Management of 12-Year-Old with Diplopia, Headache, and Normal Initial Neuroimaging

Immediate Action Required

Despite normal MRI, MRA, and MRV, you must obtain dedicated contrast-enhanced MR venography (MRV) or CT venography (CTV) immediately to definitively exclude cerebral venous sinus thrombosis, which can present with initially normal imaging and represents a life-threatening condition requiring urgent anticoagulation. 1, 2

Critical Diagnostic Steps

Urgent Vascular Imaging

• Obtain MRV with gadolinium contrast as the preferred study, as contrast-enhanced MRV is superior for evaluating sigmoid venous sinuses that are often degraded by artifact on noncontrast MRV 2, 3
• If MRV is unavailable or results remain ambiguous, CT venography is an acceptable fast alternative with high sensitivity and specificity for detecting venous sinus thrombosis 1, 2, 3
• Normal initial MRI/MRA does not exclude cerebral venous thrombosis—a dedicated venographic study must be performed when clinical suspicion exists 1, 3
• Cerebral venous thrombosis can present with headache, vomiting, and diplopia from sixth nerve palsy due to increased intracranial pressure, even with initially normal imaging 1, 2

Detailed Neuro-Ophthalmic Examination

• Perform cranial nerve examination focusing on:
  • Pattern of diplopia: horizontal diplopia worse at distance suggests sixth nerve (abducens) palsy 1
  • Pupillary function: pupil involvement dramatically changes the differential and suggests third nerve palsy requiring urgent aneurysm exclusion 1, 4
  • Check for multiple ipsilateral cranial nerve palsies (III, IV, VI) suggesting cavernous sinus pathology 1
  • Funduscopic examination for papilledema indicating increased intracranial pressure 1, 5

Laboratory Workup

• If venography remains negative, obtain:
  • Complete blood count to evaluate for severe iron deficiency anemia, which can present identically with diplopia, headache, vomiting, and papilledema 5
  • Inflammatory markers (ESR, CRP) if patient over 60 years to exclude giant cell arteritis 4
  • Consider lumbar puncture with opening pressure measurement if imaging negative, to evaluate for idiopathic intracranial hypertension 1, 6, 5

Primary Differential Diagnoses

Most Likely: Post-Viral Sixth Nerve Palsy

• Cranial nerve VI (abducens) is the most common isolated nerve palsy in post-viral cases in children 1
• The preceding vomiting and headache may represent a viral prodrome 1
• Presents with acute onset horizontal double vision, worse at distance than near, with worsening diplopia on lateral gaze toward affected side 1

Must Exclude: Cerebral Venous Thrombosis

• Can mimic idiopathic intracranial hypertension but represents a serious condition requiring anticoagulation 1, 2
• Progressive symptoms occur in 56% of cases with median delay from symptom onset to diagnosis of 7 days 2
• Headache occurs in nearly 90% of CVT patients 2

Consider: Idiopathic Intracranial Hypertension

• Can show venous outflow obstruction on MRV in 52% of cases 2
• Presents with headache, papilledema, visual disturbances, and diplopia from sixth nerve palsy 3
• Reversibility of venous outflow obstruction can be seen on MRV after lumbar puncture 7

Symptomatic Management While Awaiting Diagnosis

• Antiemetics for nausea control if vomiting recurs 1
• Eye patching or occlusion therapy to temporize diplopia symptoms 1
• Monitor for red flags: progression of neurological deficits, altered consciousness, or seizures suggesting CVT with venous infarction 1

Critical Pitfalls to Avoid

• Never assume normal initial MRI excludes cerebral venous thrombosis—dedicated venography is mandatory 1, 2
• Do not delay vascular imaging if there is any concern for third nerve palsy with pupil involvement, as aneurysm must be excluded urgently 1, 4
• Even partial extraocular muscle involvement or incomplete ptosis cannot exclude a compressive lesion 1
• Do not perform lumbar puncture before neuroimaging in patients with suspected increased intracranial pressure 7

Consultation and Follow-Up

• Immediate neurology/neurosurgery consultation if CVT confirmed for anticoagulation consideration 2
• Ophthalmology referral for patients with isolated fourth or sixth nerve palsies in absence of other neurological signs for outpatient work-up 4
• Urgent lumbar puncture with opening pressure if increased ICP suspected without mass lesion on imaging 2