Monitoring and Management of Idiopathic Intracranial Hypertension (IIH)
The recommended approach to monitoring IIH requires structured follow-up based on papilledema grade and visual field status, with regular assessment of visual function, funduscopic examination, and headache management. 1
Diagnostic Criteria and Classification
IIH is diagnosed using the modified Dandy criteria, which require:
- Elevated opening pressure (≥25 cm H₂O)
- Normal neuroimaging
- Normal CSF composition
- Normal neurological examination (except for papilledema and possible sixth nerve palsy) 2
IIH can be classified as:
- Typical IIH: Obese females of reproductive age (BMI >30 kg/m²)
- Atypical IIH: Non-obese patients requiring investigation for secondary causes
- Fulminant IIH: Rapid onset with severe visual loss
- IIH without papilledema (IIHWOP) 2
Monitoring Protocol
Visual Function Monitoring
All patients with papilledema should have documented:
- Visual acuity
- Pupil examination
- Formal visual field assessment
- Dilated fundal examination to grade papilledema
- BMI calculation 1
Follow-up Intervals Based on Papilledema Grade and Visual Field Status
| Papilledema Grade | Normal | Improving | Stable | Worsening |
|---|---|---|---|---|
| Atrophic | 4-6 months | Within 4 weeks | - | - |
| Mild | 6 months | 3-6 months | 3-4 months | Within 4 weeks |
| Moderate | 3-4 months | 1-3 months | 1-3 months | Within 2 weeks |
| Severe | 1-3 months | Within 4 weeks | Within 1 week | - |
Note: Once papilledema resolves, hospital visual monitoring may no longer be required, but caution is needed for asymptomatic patients at presentation who may remain asymptomatic during recurrence. 1
Documentation Methods
- Serial optic nerve head photographs
- Optical Coherence Tomography (OCT) imaging
- Transorbital ultrasound (though with variable cut-off values) 1
Management Algorithm
1. Weight Management (First-line Disease-modifying Therapy)
- For patients with BMI >30 kg/m², weight loss of up to 15% may be necessary for remission 2
- Referral to weight management services is recommended
2. Pharmacological Management
First-line: Acetazolamide
Alternatives if acetazolamide not tolerated:
- Topiramate (beneficial for weight loss, migraine control, and carbonic anhydrase inhibition)
- Zonisamide (if topiramate has excessive side effects)
- For patients with migraine: Candesartan (lacks weight gain and depressive side effects)
- Venlafaxine (weight neutral and helps with depression)
- Botulinum toxin A (for coexisting chronic migraine) 1
3. Surgical Interventions (for medically refractory cases)
Indicated when:
- Medical therapy fails
- Visual function deteriorates
- Headaches persist despite medical management 2
Options include:
- CSF shunting (preferred due to lower revision rate)
- Optic nerve sheath fenestration
- Venous sinus stenting (not currently recommended for headache alone) 1, 2
4. Headache Management
- Treat coexisting migrainous headaches
- CSF diversion is generally not recommended for headache alone
- For shunted patients with headaches:
- Consider shunt failure or overdrainage
- Conservative management with migraine therapies
- Address medication overuse
- Consider ICP monitoring in medication-refractory cases 1
Special Considerations
Pregnancy
- Multidisciplinary communication among clinicians throughout pregnancy, delivery, and postpartum
- Acetazolamide is not recommended during pregnancy per manufacturers
- Topiramate should not be used in pregnancy due to higher fetal abnormality rates
- No specific mode of delivery is recommended based on IIH diagnosis
- For acute exacerbations with imminent vision loss, consider serial lumbar punctures as a temporary measure 1
IIH Without Papilledema (IIHWOP)
- Manage as typical IIH with weight management counseling
- Focus on headache management
- Surgical interventions should not be routinely considered 1
Common Pitfalls and Caveats
Misdiagnosis: Direct ICP monitoring is the gold standard for determining ICP and can reduce misdiagnosis. In one study, only 12% of patients with elevated opening pressure on lumbar puncture had consistently elevated ICP on direct monitoring 3.
Medication Management: Preventative drugs need to be started slowly and increased to therapeutic doses for at least 3 months to enable a proper trial 1.
Surgical Decisions: Shunt revision should not be routinely undertaken unless there is papilledema and risk of visual deterioration 1.
Follow-up After Papilledema Resolution: Patients who were asymptomatic at presentation may remain asymptomatic during recurrence, requiring longer-term follow-up 1.
Distinguishing IIH Headaches from Migraines: Failure to optimize ICP may render migrainous headaches difficult to treat 1.