In a patient with an empty sella on brain imaging who presents with persistent headache, transient visual obscurations, papilledema, or diplopia, what is the appropriate work‑up for idiopathic intracranial hypertension (IIH)?

Work-Up for Idiopathic Intracranial Hypertension When Empty Sella is Found on Imaging

When an empty sella is discovered on brain imaging with clinical suspicion for IIH, proceed immediately with formal ophthalmologic examination for papilledema, obtain MRI brain and orbits with MR venography, and perform lumbar puncture with opening pressure measurement to confirm elevated intracranial pressure (≥250 mm H₂O). 1, 2

Initial Clinical Assessment

Key Symptoms to Elicit

Empty sella is a typical neuroimaging feature of raised intracranial pressure and warrants systematic evaluation for IIH. 1 Focus your history on:

• Headache characteristics: Present in nearly 90% of IIH patients, typically holocephalic or unilateral throbbing, worse in morning after supine positioning, and worsened by Valsalva maneuver. 2, 3
• Visual symptoms: Transient visual obscurations (bilateral darkening of vision lasting seconds), visual blurring, or progressive visual loss. 1, 2
• Pulsatile tinnitus: A highly specific symptom suggesting elevated ICP. 1, 2
• Diplopia: Typically horizontal due to sixth nerve palsy from elevated pressure. 1, 2, 4

Critical Physical Examination

• Fundoscopic examination for papilledema: This is mandatory and the key diagnostic finding. 1, 2 Papilledema confirms the diagnosis when combined with elevated opening pressure and appropriate imaging. 2
• Visual field testing: Essential to detect visual loss, which may not be recognized by patients. 5, 6
• Neurologic examination: Should be otherwise normal except for possible sixth nerve palsy; any other focal deficits suggest alternative diagnosis. 2, 6

Diagnostic Imaging Protocol

Primary Imaging Modality

MRI of the head and orbits is the most useful imaging modality and should be obtained with specific sequences. 2, 7 This provides superior resolution compared to CT for detecting signs of elevated ICP. 2

Essential MRI Sequences

• Brain MRI with and without contrast: To exclude secondary causes (mass, hydrocephalus, meningeal enhancement) and confirm normal brain parenchyma. 2, 7
• Dedicated orbital imaging: Coronal fat-saturated T2-weighted sequences to evaluate optic nerve sheaths. 2, 7
• MR venography (MRV): To evaluate for venous sinus stenosis and exclude cerebral venous sinus thrombosis. 2, 7

Key Neuroimaging Findings Supporting IIH Diagnosis

Beyond the empty sella already identified, look for: 1, 2, 7

• Posterior globe flattening: 56% sensitivity, 100% specificity for high ICP. 2, 7
• Enlarged optic nerve sheath: Mean diameter 4.3 mm in IIH versus 3.2 mm in controls. 2, 7
• Horizontal tortuosity of optic nerve: 68% sensitivity, 83% specificity. 2
• Intraocular protrusion of optic nerve head: 40% sensitivity, 100% specificity. 2
• Transverse sinus stenosis: Commonly seen on MRV, though may be secondary to elevated pressure rather than primary. 1, 7

Lumbar Puncture: The Definitive Diagnostic Test

Technique and Measurement

Perform lumbar puncture with the patient in lateral decubitus position, legs extended, to accurately measure opening pressure. 1, 2

Diagnostic Criteria for Opening Pressure

• ≥250 mm H₂O: Diagnostic for IIH and defines need for urgent intervention. 2
• 180-250 mm H₂O: Concerning but potentially not requiring immediate intervention; clinical correlation essential. 2
• CSF composition: Must be normal (no organisms, normal cell count, normal protein and glucose) to diagnose IIH. 1, 2, 6

Therapeutic Lumbar Puncture

If opening pressure is ≥250 mm H₂O, remove CSF to reduce pressure to 50% of opening pressure or 200 mm H₂O, whichever is greater. 2 Removal of 20-30 mL may provide immediate symptom relief. 2

Exclude Secondary Causes

Medication Review

Identify and discontinue medications that can cause or exacerbate IIH: 3

• Tetracyclines (including doxycycline)
• Vitamin A and retinoids (especially >10,000 IU daily)
• Corticosteroids (particularly withdrawal)
• Growth hormone
• Thyroxine
• Lithium

Endocrine Screening

Although empty sella can be associated with pituitary dysfunction, basic hormonal screening may be necessary to rule out central hypothyroidism and assess adrenal axis. 2 However, this is secondary to establishing the IIH diagnosis.

Diagnostic Pitfalls to Avoid

• Do not assume normal neurological examination excludes IIH: Visual loss may progress asymptomatically. 2, 5
• Do not rely on CT imaging alone: MRI is far more sensitive for detecting secondary signs of elevated ICP. 2, 7
• Do not perform serial lumbar punctures for management: These are not recommended for ongoing treatment. 3
• Recognize IIH can occur without papilledema: Although rare, obese women with chronic daily headache, pulsatile tinnitus, empty sella, and elevated opening pressure may have IIH without papilledema. 8

When to Expedite Work-Up

Urgent evaluation is required when: 1

• Evidence of declining visual function (progressive visual field loss, decreasing visual acuity)
• Severe papilledema (Frisen grade 3-5)
• Rapidly progressive symptoms

In these cases, consider temporizing lumbar drain while planning urgent surgical intervention (CSF diversion or optic nerve sheath fenestration) to preserve vision. 1

Summary Algorithm

1. Clinical assessment: Detailed history for IIH symptoms + fundoscopic exam for papilledema + visual field testing. 1, 2
2. MRI brain and orbits with MRV: Confirm empty sella, identify other signs of elevated ICP, exclude secondary causes. 2, 7
3. Lumbar puncture: Measure opening pressure (diagnostic if ≥250 mm H₂O) + confirm normal CSF composition. 2
4. Medication review: Discontinue potential causative agents. 3
5. Ophthalmology referral: For baseline visual assessment and monitoring. 1
6. Neurology or neurosurgery consultation: If diagnosis confirmed, especially with visual compromise. 1