What is the diagnosis and treatment for a patient with progressive vision blurring in both eyes, papilledema, and increased intracranial pressure, who has been experiencing symptoms for 3 years?

Diagnosis: Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

This patient's 3-year history of progressive bilateral vision blurring with papilledema on examination is most consistent with idiopathic intracranial hypertension (IIH), and requires urgent MRI brain and orbits with venography followed by lumbar puncture to confirm elevated opening pressure and guide treatment. 1, 2

Diagnostic Workup Algorithm

Immediate Imaging (Within 24 Hours)

MRI brain and orbits with MR venography is the mandatory first-line imaging study to exclude structural causes of elevated intracranial pressure and identify characteristic findings of IIH. 3, 1, 2, 4

Key MRI findings to assess:

• Posterior globe flattening (56% sensitivity, 100% specificity for elevated ICP) 3, 2
• Empty or partially empty sella (highly specific for raised ICP) 3, 2, 5
• Optic nerve sheath enlargement (mean 4.3 mm in IIH vs 3.2 mm in controls) 3
• Horizontal tortuosity of optic nerves (68% sensitivity, 83% specificity) 3, 2
• Intraocular protrusion of optic nerve head (40% sensitivity, 100% specificity) 3, 2
• Transverse sinus stenosis (commonly associated with elevated ICP) 1, 5

MR venography is critical to exclude cerebral venous sinus thrombosis, which mimics IIH but requires anticoagulation rather than standard IIH management. 1, 2 If MRI is contraindicated, CT venography is an acceptable alternative. 3, 5

Lumbar Puncture (After Normal Imaging)

Following confirmation of normal brain parenchyma without mass, hydrocephalus, or structural lesion, lumbar puncture with opening pressure measurement is mandatory. 1, 2, 4

Diagnostic criteria:

• Opening pressure >250 mm H₂O confirms elevated ICP (measured in lateral decubitus position) 1, 2, 5
• Normal CSF composition (absence of elevated white cells or organisms distinguishes IIH from infectious meningitis) 1, 5
• Pressures 180-250 mm H₂O are concerning but may not require immediate intervention 5

During the initial lumbar puncture, remove 20-30 mL of CSF to provide immediate symptom relief, and if opening pressure ≥250 mm H₂O, reduce pressure to 50% of opening or 200 mm H₂O, whichever is greater. 5

Essential Clinical Assessment

Before imaging, measure blood pressure to exclude malignant hypertension as a cause of papilledema. 2, 4

Assess for characteristic IIH symptoms:

• Headache (present in 90% of IIH patients—typically holocephalic or unilateral throbbing, worse in morning after supine positioning, improving with upright posture) 1, 5
• Transient visual obscurations (temporary episodes of blurred or lost vision from transient optic nerve head ischemia) 1, 2, 6
• Pulsatile tinnitus (common in IIH) 1, 5
• Horizontal diplopia (from sixth nerve palsy due to elevated ICP) 3, 1, 2

Check for sixth nerve palsy specifically, as this is the only cranial nerve finding expected in IIH; other cranial neuropathies suggest alternative diagnoses. 3, 2, 5

Secondary Causes to Exclude

Several conditions can mimic IIH and require different management:

• Cerebral venous sinus thrombosis (requires anticoagulation, not standard IIH treatment—hence the critical importance of venography) 1, 5
• Medications: tetracyclines, vitamin A, retinoids, growth hormone, thyroxine, lithium 3, 1
• Endocrine disorders: Addison disease, hypoparathyroidism 3, 1
• Intracranial arteriovenous fistulas 1

Treatment Strategy

First-Line Medical Management

Weight loss is the most effective treatment for putting IIH into remission in overweight patients and should be initiated immediately. 1, 5, 4

Acetazolamide is first-line pharmacologic therapy for IIH with mild to moderate visual loss. 1, 2, 5, 4

Serial lumbar punctures may be necessary if intracranial pressure remains persistently elevated despite medical therapy. 1, 5

Urgent Surgical Intervention Indications

Rapidly declining visual function requires immediate surgical intervention to prevent permanent vision loss. 1, 5

Surgical options when medical therapy fails:

• Optic nerve sheath fenestration (effective for progressive visual field loss despite resolved papilledema) 7
• Ventriculoperitoneal shunting (typical procedure of choice for refractory cases) 4
• CSF diversion procedures for persistent symptoms despite adequate medical management 1

Neurosurgical consultation is indicated if medical therapy fails or visual function deteriorates. 1, 5

Critical Pitfalls to Avoid

The absence of papilledema does NOT exclude elevated intracranial pressure—long-standing papilledema can induce optic disc changes that prevent further disc swelling, and visual atrophy can mimic regression of papilledema. 6

Progressive visual field loss can occur even after papilledema resolution if intracranial pressure remains elevated, requiring ongoing monitoring with automated perimetry. 7

Do not assume normal CT excludes elevated ICP—CT is insensitive for the subtle findings of IIH, and MRI with venography is mandatory. 1, 2

In postpubertal patients, IIH typically affects overweight females of childbearing age, but in prepubertal children, boys and girls are equally affected. 3, 1

Visual field defects in IIH typically show enlarged blind spot and mild arcuate defects that regress with pressure reduction, but some patients experience rapid progression requiring immediate effective treatment. 6