What is the management of Idiopathic Intracranial Hypertension (IIH)?

Management of Idiopathic Intracranial Hypertension (IIH)

Weight loss is the only disease-modifying therapy for IIH and should be recommended as first-line treatment for all patients with BMI >30 kg/m² 1.

Definition and Diagnosis

Idiopathic intracranial hypertension (IIH) is characterized by raised intracranial pressure without hydrocephalus, mass lesion, or identifiable cause, with normal CSF composition. It predominantly affects women of childbearing age with obesity 1, 2.

Key diagnostic criteria include:

• Papilledema
• Normal neurological examination (except for cranial nerve abnormalities)
• Normal brain imaging (MRI showing no hydrocephalus, mass, or structural abnormality)
• Normal CSF composition
• Elevated lumbar puncture opening pressure (>25 cmH₂O in adults)

Management Principles

Management of IIH follows three core principles 1:

1. Treat the underlying disease
2. Protect vision
3. Minimize headache morbidity

First-Line Management: Weight Loss

• Weight loss is the only proven disease-modifying treatment
• A weight loss of 24% can normalize intracranial pressure and improve papilledema 3
• All patients with BMI >30 kg/m² should receive counseling about weight management

Medical Management

For patients with mild to moderate papilledema and mild visual loss:

1. Acetazolamide:

   • First-line pharmacological therapy
   • Start with low dose and gradually increase as tolerated
   • Monitor for side effects (paresthesia, fatigue, altered taste, nausea)

2. Topiramate as an alternative:

   • Has carbonic anhydrase activity similar to acetazolamide
   • Additional benefits include appetite suppression and migraine prophylaxis 1, 4
   • Start with 25 mg and escalate weekly to 50 mg twice daily
   • Important: Warn women that topiramate reduces oral contraceptive efficacy 1

Surgical Management

For patients with fulminant IIH or progressive visual loss despite medical therapy:

1. CSF Diversion Procedures:

   • Ventriculoperitoneal (VP) shunt is preferred over lumboperitoneal shunt due to lower revision rates 1
   • Consider adjustable valves with anti-siphon devices to reduce low-pressure headaches
   • Complications include shunt failure, infection, and over-drainage

2. Optic Nerve Sheath Fenestration (ONSF):

   • May be considered as first-line surgical treatment in fulminant cases or asymmetric papilledema
   • Lower complication rates than CSF diversion (2.2% vs 9.4% severe complications) 5
   • Less effective for headache management (49.3% improvement) compared to vision protection (90.5% improvement for papilledema) 5

3. Venous Sinus Stenting:

   • Emerging procedure for patients with venous sinus stenosis
   • Improves papilledema in 87.1%, visual fields in 72.7%, and headaches in 72.1% of patients 5
   • Requires long-term antithrombotic therapy (>6 months)
   • Role not yet fully established in standard management 1

Important Caveats

• Serial lumbar punctures are NOT recommended for IIH management 1

• CSF is produced at 25 mL/hour, making the relief from LP short-lived

• LPs cause significant anxiety and potential chronic back pain

• Surgical treatment failure rates:

  • CSF diversion: 43.4% failure rate with 9.4% severe complications 5
  • ONSF: 9.4% failure rate with 2.2% severe complications 5
  • Venous sinus stenting: 11.3% failure rate with 2.3% severe complications 5

Management Algorithm

1. Assess visual function urgently:

   • If rapidly deteriorating vision (fulminant IIH): Immediate surgical intervention
   • If stable or mild visual changes: Medical management

2. For stable patients:

   • Initiate weight loss program for all patients with BMI >30 kg/m²
   • Start acetazolamide or topiramate
   • Regular ophthalmological monitoring

3. For progressive visual loss despite medical therapy:

   • Consider surgical options based on patient characteristics:
     • VP shunt: First-line surgical option for most patients
     • ONSF: Consider for asymmetric papilledema or when CSF diversion contraindicated
     • Venous sinus stenting: Consider if significant venous sinus stenosis identified

4. For headache management:

   • Treat according to headache phenotype
   • Address medication overuse if present
   • Consider topiramate if migraine-like headaches predominate

Monitoring

Regular ophthalmological assessments are essential to monitor for visual deterioration, including:

• Visual acuity
• Visual fields
• Papilledema grading
• Optical coherence tomography (OCT)

Early intervention is crucial to prevent permanent visual loss from chronic papilledema 3.