What is the treatment and prognosis for Idiopathic Intracranial Hypertension (IIH)?

Treatment and Prognosis of Idiopathic Intracranial Hypertension (IIH)

The management of IIH should prioritize weight loss as the foundation of treatment, with acetazolamide as first-line medical therapy, and surgical interventions reserved for cases with progressive visual loss or refractory symptoms. 1

Medical Management

First-Line Therapy

• Acetazolamide is the preferred first-line medication for IIH with mild vision loss, supported by evidence from the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) 2
• Recommended starting dose is 250-500 mg twice daily, with gradual titration as tolerated 1
• Maximum dose used in IIHTT was 4 g daily, though many patients tolerate 1 g/day; approximately 48% discontinue at mean doses of 1.5 g due to side effects 1
• Patients must be warned about common side effects including diarrhea, dysgeusia, fatigue, nausea, paresthesia, tinnitus, vomiting, depression, and rarely renal stones 1

Alternative Medical Therapies

• Topiramate may be considered as an alternative to acetazolamide, with weekly dose escalation from 25 mg to 50 mg twice daily 1
• Topiramate offers multiple benefits: carbonic anhydrase inhibition (reducing ICP), appetite suppression (promoting weight loss), and migraine prevention 3
• When prescribing topiramate, women must be informed about reduced efficacy of hormonal contraceptives and potential side effects including depression, cognitive slowing, and teratogenic risks 1
• Other diuretics such as furosemide, amiloride, and coamilofruse are sometimes used as alternative therapies, though evidence for their efficacy is limited 1

Headache Management in IIH

• Headache is a common and disabling symptom in IIH, often persisting even after ICP normalization 4
• Migrainous phenotype is noted in 68% of IIH patients with headache 1
• Patients should be warned about medication overuse headache risk (use of simple analgesics >15 days/month or opioids/triptans >10 days/month) 1
• Short-term pain management may include NSAIDs or paracetamol; indomethacin may be advantageous due to its ICP-reducing effect 1
• Opioids should not be prescribed for headache management 1
• For migrainous headaches, triptans may be used acutely (limited to 2 days/week or maximum 10 days/month) in combination with NSAIDs/paracetamol and antiemetics 1
• Preventive migraine medications should be considered, avoiding those that increase weight (beta-blockers, tricyclic antidepressants, sodium valproate) 1
• Weight-neutral options like candesartan or venlafaxine may be preferable for migraine prevention 1

Surgical Management

Indications for Surgical Intervention

• Surgery should be considered for patients with progressive visual loss despite medical therapy 1
• Approximately 6% of patients require surgical intervention for severe IIH 4

Cerebrospinal Fluid (CSF) Diversion

• Ventriculoperitoneal (VP) shunt is the preferred CSF diversion procedure due to lower revision rates per patient 1
• Lumboperitoneal (LP) shunts are an alternative option 1
• Adjustable valves with antigravity or antisiphon devices should be considered to reduce low-pressure headaches 1
• Neuronavigation should be used when placing VP shunts 1
• Treatment failure rates include worsening vision after stabilization in 34% at 1 year and 45% at 3 years 1
• CSF diversion for headache alone is generally not recommended, as 68% continue to have headaches at 6 months and 79% by 2 years 1

Other Surgical Options

• Optic nerve sheath fenestration (ONSF) may be considered for asymmetric papilledema or as first-line treatment in fulminant cases 1
• ONSF has fewer complications than CSF diversion but should be performed by experienced clinicians 1
• Neurovascular stenting remains investigational and is not established as standard treatment for IIH 1
• Long-term antithrombotic therapy (>6 months) is required following neurovascular stenting 1

Prognosis

• Long-term visual and symptomatic prognosis in IIH is generally excellent with appropriate treatment 4
• Visual field measures and retinal nerve fiber layer thickness typically improve with treatment 4
• Quality of life may be significantly impacted, with depression common among IIH patients 5
• Higher risk of visual loss is associated with male gender, Black race, severe obesity, and anemia 5
• Headaches frequently persist even after successful treatment of increased ICP 4, 5

Important Considerations and Pitfalls

• Serial lumbar punctures are not recommended for long-term management of IIH despite providing temporary relief 1
• CSF is produced at 25 mL/hour, so volume removed during LP is rapidly replaced 1
• LPs can cause significant anxiety and may lead to acute and chronic back pain 1
• Lifestyle modifications, particularly weight loss, remain foundational to treatment 1
• Medication overuse must be addressed, as it can prevent optimization of preventative treatments 1
• Non-opioids and triptans can be stopped abruptly or weaned within a month, while opioids should be gradually removed 1