What is the diagnosis and treatment for a 30-year-old female with progressively worsening headaches over 7 months, occasional vision changes in her right eye, and improvement in symptoms while on prednisone (corticosteroid), with headaches worsening when in a supine position?

Diagnosis: Idiopathic Intracranial Hypertension (IIH)

This 30-year-old female presents with classic features of idiopathic intracranial hypertension: progressively worsening headaches over months, vision changes, headaches that worsen when lying down (supine position), and improvement with corticosteroids. 1

Clinical Reasoning for IIH Diagnosis

The constellation of symptoms strongly points to IIH:

• Progressive headaches over 7 months that worsen with lying down (increased intracranial pressure in supine position) 1
• Vision changes in the right eye suggest papilledema or transient visual obscurations, which are hallmark features of IIH 1
• Improvement on prednisone is consistent with IIH, as corticosteroids reduce intracranial pressure 1
• Demographics fit the typical IIH profile: female of childbearing age (30 years old) 1

The headache worsening when lying down is a critical red flag feature that indicates elevated intracranial pressure, as this position increases venous pressure and worsens symptoms. 2, 1

Immediate Diagnostic Workup

Obtain urgent MRI brain with contrast within 24 hours; if MRI is unavailable, perform urgent CT brain followed by MRI when available. 1

Required Imaging Studies

• MRI brain with contrast is the preferred initial test to exclude secondary causes of raised intracranial pressure (mass lesions, hydrocephalus, structural abnormalities) 1
• CT or MR venography is mandatory within 24 hours to exclude cerebral sinus thrombosis, which can mimic IIH 1
• Look for specific MRI findings supporting IIH: posterior globe flattening (56% sensitivity, 100% specificity), intraocular protrusion of optic nerve (40% sensitivity, 100% specificity), horizontal tortuosity of optic nerve (68% sensitivity, 83% specificity), and enlarged optic nerve sheath 1

Essential Clinical Examination

• Perform fundoscopic examination immediately to document papilledema, which is the hallmark finding in IIH 1
• Complete cranial nerve examination looking specifically for sixth nerve palsy (the only cranial nerve typically affected in IIH); if other cranial nerves are involved, consider alternative diagnoses 1
• Visual field testing to assess for peripheral vision loss 1

Lumbar Puncture Requirements

After normal neuroimaging, perform lumbar puncture with opening pressure measurement in the lateral decubitus position with legs extended and patient relaxed. 1

• CSF opening pressure ≥25 cm H₂O (≥250 mm H₂O) is required for diagnosis 1
• Proper technique is critical: patient must be in lateral decubitus position, legs extended, relaxed, breathing normally, and measurement taken after pressure stabilizes 1
• If initial opening pressure is <25 cm H₂O but clinical suspicion remains high, arrange close follow-up with repeat lumbar puncture at 2 weeks, as pressure may fluctuate 1

Treatment Algorithm

Immediate Management

Do not continue prednisone as monotherapy for IIH. While corticosteroids can temporarily reduce intracranial pressure, they are not the standard treatment for IIH and can worsen the condition long-term by causing weight gain (a major risk factor for IIH). 1

Definitive Treatment Based on Severity

For patients with papilledema but stable vision:

• Weight loss is the most effective long-term treatment if BMI >30 kg/m² 1
• Acetazolamide is first-line medical therapy (typically starting 500-1000 mg daily, titrated up to 2000-4000 mg daily in divided doses) 1

For patients with evidence of declining visual function:

• Immediate surgical intervention is required to preserve vision when there is pathologically high CSF pressure with visual deterioration 1
• Temporizing measure: lumbar drain can protect vision while planning urgent surgical treatment 1
• Surgical options include optic nerve sheath fenestration or ventriculoperitoneal/lumboperitoneal shunt 1

Acute Symptom Management

For headache relief while initiating definitive treatment:

• NSAIDs (such as ketorolac) are first-line for acute headache 3
• Add metoclopramide 10 mg IV for both antiemetic effects and synergistic analgesia if nausea present 3
• Avoid opioids and butalbital-containing compounds as they lead to medication overuse headache and dependency 2, 3

Critical Pitfalls to Avoid

• Do not miss papilledema on fundoscopic examination - this is the hallmark finding and missing it delays diagnosis 1
• Do not skip venography - cerebral sinus thrombosis can present identically to IIH and requires anticoagulation, not IIH treatment 1
• Do not measure opening pressure incorrectly - improper positioning (sitting up, legs flexed, patient anxious) will give falsely elevated readings 1
• Do not delay ophthalmology referral - permanent vision loss can occur if treatment is delayed in patients with declining visual function 1
• Do not continue corticosteroids long-term - while they may provide temporary symptom relief, they worsen the underlying condition by promoting weight gain 1

Follow-up Requirements

• Repeat lumbar puncture if significant deterioration of visual function occurs to reassess CSF pressure and guide management escalation 1
• Regular ophthalmology follow-up with visual field testing to monitor for progressive vision loss 1
• Serial fundoscopic examinations to assess papilledema resolution 1