What are the recent updates in the management of Idiopathic Intracranial Hypertension (IIH)?

Recent Updates in Idiopathic Intracranial Hypertension Management

Weight loss has emerged as the only disease-modifying therapy for IIH and must be the cornerstone of treatment for all patients with BMI >30 kg/m², with a target of 5-15% total body weight reduction to achieve remission. 1

Core Management Principles

Weight Management as Primary Therapy

• All patients with BMI >30 kg/m² require immediate counseling about weight management at diagnosis 1
• Refer patients to community or hospital-based weight management programs 1
• Bariatric surgery should be considered for appropriate candidates requiring sustained weight loss 1
• Weight gain during the year before diagnosis is significantly associated with visual field deterioration 2

Medical Therapy Updates

Acetazolamide Dosing and Evidence:

• Start acetazolamide at 250-500 mg twice daily, gradually titrating to maximum 4 g daily as tolerated 1
• The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) demonstrated that acetazolamide combined with weight loss improves visual field outcomes, papilledema, intracranial pressure, and quality of life in patients with mild vision loss 3, 4
• Only 44% of patients tolerate the maximum 4 g daily dose, with most tolerating 1 g/day 1
• Approximately 48% discontinue acetazolamide at mean doses of 1.5 g due to adverse effects including diarrhea, dysgeusia, fatigue, nausea, paresthesias, tinnitus, depression, and rarely renal stones 1

Topiramate as Alternative:

• Topiramate may be used with weekly dose escalation from 25 mg to 50 mg twice daily, offering both carbonic anhydrase activity and appetite suppression 5
• Women must be informed that topiramate reduces oral contraceptive efficacy 5

Surgical Management Updates

CSF Diversion Procedures:

• Ventriculoperitoneal (VP) shunt is the preferred CSF diversion procedure due to lower revision rates per patient compared to lumbar-peritoneal shunts 5
• Use neuronavigation for VP shunt placement as best practice 5
• Adjustable valves with antigravity or antisiphon devices should be utilized to reduce low pressure headache risk 5
• Treatment failure rates are significant: 34% experience worsening vision at 1 year and 45% at 3 years 5
• Headache fails to improve in one-third to one-half of patients 5

Optic Nerve Sheath Fenestration (ONSF):

• ONSF is considered first-line for malignant fulminant cases and asymmetric papilledema causing unilateral visual loss 5
• ONSF has fewer complications than CSF diversion with no reported mortalities in the literature 5
• Temporary adverse effects include diplopia, anisocoria, and optic nerve head hemorrhages; rare permanent sequelae include retinal artery occlusions 5
• Must be performed only by experienced clinicians trained in this technique 5

Venous Sinus Stenting - Emerging Option:

• The role of neurovascular stenting in IIH is not yet established, though recent studies show it as a well-tolerated and effective surgical alternative for refractory IIH 5, 4, 6
• Many IIH patients have anatomical abnormalities including stenosis of the dominant or both transverse sinuses 5
• Complications include short-lived ipsilateral headache, stent-adjacent stenosis requiring retreatment in one-third, and rarely vessel perforation, subdural hematoma, stent migration, and thrombosis 5
• Long-term antithrombotic therapy is required for longer than 6 months following stenting 5
• Appropriate patient selection requires established IIH diagnosis, documented papilledema or visual disturbance, LP opening pressure >25 cm H₂O, focal transverse-to-sigmoid sinus narrowing on venography, and pressure gradient ≥10 mm Hg across the stenosis 6

Management Algorithm Based on Disease Severity

Mild to Moderate IIH:

• Weight loss program plus acetazolamide is the standard approach 1
• Regular ophthalmology assessments to monitor visual function 1
• Repeat diagnostic lumbar puncture if visual function deteriorates to reassess intracranial pressure 1

Severe or Rapidly Progressive Visual Loss:

• Urgent surgical intervention is mandatory when there is evidence of declining visual function 5, 1
• A temporizing lumbar drain may protect vision while planning definitive surgical treatment 5, 1
• Surgical options include CSF diversion (preferred in UK) or ONSF for precipitous visual decline 1

What NOT to Do

Serial Lumbar Punctures:

• Serial lumbar punctures are not recommended for IIH management 5, 1
• Relief from LP is short-lived as CSF is secreted at 25 mL/hour, rapidly replacing removed volume 5
• LPs cause significant anxiety and can lead to acute and chronic back pain 5

Diagnostic Updates

Neuroimaging Features:

• Typical MRI findings include empty/partially empty sella, increased optic nerve tortuosity, enlarged optic nerve sheath, flattened posterior globe, intraocular protrusion of optic nerve head, and bilateral transverse sinus stenosis 5
• CT or MR venography is mandatory within 24 hours to exclude cerebral sinus thrombosis 7

CSF Opening Pressure:

• CSF opening pressure must be ≥25 cm H₂O measured in lateral decubitus position with legs extended and patient relaxed 7, 8

Common Pitfalls to Avoid

• Failing to prioritize weight management as the primary disease-modifying intervention 1
• Relying solely on medical therapy without addressing underlying obesity 1
• Delaying surgical intervention when visual function is declining 5, 1
• Using medications that exacerbate IIH (tetracyclines, vitamin A, retinoids, steroids, growth hormone, thyroxine, lithium) 1
• Inadequate monitoring leading to missed visual deterioration (34% worsen at 1 year, 45% at 3 years) 5