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neuro.idiopathic-intracranial-hypertension.v1PRODUCTION
neuro.idiopathic-intracranial-hypertension.v1

Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)

neurologyacutesubacutechronicadultpregnancy
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12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Vision-threatening intracranial hypertension in a young woman with elevated BMI; pivot on headache + papilledema + normal neuro exam + normal imaging + raised LP opening pressure + normal CSF (Friedman 2013 PMID 23966248)

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IIH suspected on syndromic grounds (papilledema + headache phenotype)

Patient inputs (15)

Adult IIH peaks in third/fourth decade; pediatric IIH has lower opening-pressure cut-off (≥28 cmH2O obese, ≥25 lean) and different sex distribution (Friedman 2013 PMID 23966248)

IIH ~90% female of reproductive age; male IIH is atypical and lower prevalence but more likely to lose vision (Markey 2015 PMID 26700907)

BMI ≥30 is the dominant modifiable risk factor; BMI ≥35 is the IIH:WT enrolment threshold and the strongest bariatric-surgery indication (Mollan IIH:WT 2021 PMID 33900360; Abbott 2023 PMID 37813577)

Pregnancy contraindicates acetazolamide (FDA category C / animal teratogenic; pragmatic avoidance) and topiramate (cleft palate); pregnancy IIH managed with serial LP + ophthalmology shared-decision (Mollan 2018 PMID 29903905)

IIH-trigger medications (tetracyclines, vitamin A / retinoids, cyclosporine, lithium, growth hormone, all-trans retinoic acid) — drug-induced secondary intracranial hypertension is reversible on withdrawal; Friedman 2013 mandates exclusion + de-prescription (Friedman 2013 PMID 23966248; Mollan 2018 PMID 29903905)

Papilledema is a Friedman 2013 required criterion; Frisén grade 0-5 and OCT RNFL drive severity stratification — grade ≥3 + RNFL >300 µm marks severe (Friedman 2013 PMID 23966248; Wall IIHTT 2014 PMID 24756514)

CSF opening pressure (cmH2O) measured laterally with legs extended; Friedman 2013 ≥25 adult, ≥28 in obese, ≥28 in sedated/obese children, ≥25 in lean children — REQUIRED for diagnosis (Friedman 2013 PMID 23966248)

Normal CSF cell count, protein, glucose REQUIRED for IIH diagnosis; pleocytosis or elevated protein excludes IIH and points to meningitis / inflammatory / neoplastic cause (Friedman 2013 PMID 23966248)

MRI brain + MRV REQUIRED to exclude mass / hydrocephalus / CSF leak / CVST; positive IIH signs include empty sella, ONS dilation, transverse-sinus stenosis (Friedman 2013 PMID 23966248; Mollan 2018 PMID 29903905)

Humphrey visual field 24-2 perimetric mean deviation is the IIHTT operative outcome measure (NOT visual acuity) — quantifies field loss and drives severity / surgical-rescue decisions (Wall IIHTT 2014 PMID 24756514)

OCT RNFL thickness quantifies papilledema severity beyond Frisén grading; RNFL >300 µm marks severe papilledema; trend correlates with treatment response (Wall IIHTT 2014 PMID 24756514; Mitchell 2019 PMID 30865008)

eGFR drives acetazolamide renal-adjusted dosing (avoid if CrCl<10; reduce in CKD) and topiramate adjustment (Mollan 2018 PMID 29903905)

Baseline + serial HCO3 monitoring under acetazolamide (carbonic-anhydrase inhibition causes metabolic acidosis; symptomatic acidosis or HCO3 <18 → dose-reduce; Wall IIHTT 2014 PMID 24756514)

Recent weight gain (5-15% over months) is a major precipitant in adult IIH and a recurrence trigger after remission (Markey 2015 PMID 26700907; Abbott 2023 PMID 37813577)

PCOS and OSA are over-represented in IIH cohorts and share an obesity-hyperandrogenism axis; OSA worsens nocturnal ICP and may co-treat (Markey 2015 PMID 26700907; Markey 2016 PMID 27186074)

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Severity triggers (10)

10 need judgement
  • informationallife_threateningfulminant_iih_vision_loss_lt_4wk
    Vision loss progressing over <4 weeks from onset (Mollan 2018 PMID 29903905)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveresevere_papilledema_frisen_4_5_or_rnfl_300
    Frisén grade 4-5 OR OCT RNFL >300 µm at presentation (Wall IIHTT 2014 PMID 24756514; Mollan 2018 PMID 29903905)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevererapid_field_progression_on_treatment
    Worsening HVF perimetric mean deviation on optimal medical therapy (Wall IIHTT 2014 PMID 24756514)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverepregnancy_iih_with_worsening_vision
    Pregnancy-IIH with progressive vision loss (Mollan 2018 PMID 29903905)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatedrug_induced_secondary_intracranial_hypertension
    Symptom onset within months of starting tetracyclines / retinoids / cyclosporine / lithium / GH / all-trans retinoic acid (Friedman 2013 PMID 23966248)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatetransverse_sinus_stenosis_predominant_phenotype
    Transverse-sinus stenosis with pressure gradient ≥8 mmHg on venography in IIH (Gurney 2020 PMID 32021528)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderateiih_recurrence_with_weight_regain
    Recurrent papilledema or field loss with weight regain after remission (Abbott 2023 PMID 37813577)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderateacetazolamide_intolerance_or_acidosis
    Symptomatic metabolic acidosis HCO3 <18 OR disabling paresthesias / dysgeusia / nephrolithiasis on acetazolamide (Wall IIHTT 2014 PMID 24756514)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderateatypical_iih_male_lean_child
    Atypical IIH presentation (male, lean BMI<30, or paediatric) (Markey 2015 PMID 26700907)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmildiih_without_papilledema_iih_wop
    IIH-without-papilledema phenotype — raised opening pressure + chronic daily headache + clean CSF/imaging without papilledema (Friedman 2013 PMID 23966248)
    Trigger could not be auto-evaluated — needs clinician judgement.

Workflow calculators

Run this disease's risk and dosing calculators inline.

TREATMENTrequiredDrives dose adjustment
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Recommended regimen

IIH four-pillar treatment ladder — weight loss + carbonic-anhydrase inhibitor + topiramate adjunct + surgical rescue (Mollan 2018 PMID 29903905 + Wall IIHTT PMID 24756514 + Mollan IIH:WT 2021 PMID 33900360 + Abbott 2023 PMID 37813577 + Gurney 2020 PMID 32021528)
axis: iih_treatment_ladderstep 1 - Pillar 1 — Disease-modifying weight loss (Mollan IIH:WT 2021 PMID 33900360; Abbott 2023 PMID 37813577)
Selected step "Pillar 1 — Disease-modifying weight loss (Mollan IIH:WT 2021 PMID 33900360; Abbott 2023 PMID 37813577)" — BMI ≥30 (typical IIH) at diagnosis and at every follow-up
  • lifestyle_weight_loss_multicomponent
    first line
    lifestyle
    triggers: BMI_30_to_34_9, patient_preference_for_non_surgical
    Multicomponent lifestyle intervention (diet + activity + behaviour) — Abbott 2023 grade B for BMI<35 (PMID 37813577); 5-15% weight loss reduces ICP and headache disability (Markey 2015 PMID 26700907)
  • bariatric_surgery_referral
    first line
    lifestyle
    triggers: BMI_>=35, failed_lifestyle_at_12_months, severe_or_fulminant_IIH
    Bariatric surgery is superior to community weight management at lowering ICP and inducing remission (Mollan IIH:WT 2021 PMID 33900360 + 2022 substudy PMID 35790425); Abbott 2023 grade A for BMI≥35 (PMID 37813577)
  • liraglutide
    add on
    GLP1_receptor_agonist
    0.6 mg SC daily, titrate to 3.0 mg SC daily over 5 weeks • SC • daily
    triggers: BMI_>=30, no_personal_history_MTC_or_MEN2, patient_preference_for_pharmacologic_weight_loss, no_pregnancy
    GLP-1 receptor agonists shown to reduce ICP and produce weight loss in IIH pilot data — emerging adjunct flagged in Mollan 2019 review (PMID 30865008); not yet AHA/UK consensus first-line
    rxcui 475968

outpatient playbook — drug actions (3)

  1. 1. acetazolamide
    rxcui 167
    Maintain at lowest effective dose 500 mg-4 g/day divided; taper on sustained remission • PO • BID-QID
    trigger: Established IIH on maintenance
    Wall IIHTT 2014 (PMID 24756514)
  2. 2. topiramate
    rxcui 38404
    50-100 mg/day if headache-predominant • PO • daily-BID
    trigger: Headache-predominant IIH not on bariatric path
    Mollan 2018 (PMID 29903905)
  3. 3. liraglutide
    rxcui 475968
    0.6 → 3.0 mg SC daily over 5 weeks • SC • daily
    trigger: Adjunctive pharmacologic weight loss in BMI ≥30 patient unable to access bariatric surgery
    Emerging GLP-1RA evidence (Mitchell 2019 PMID 30865008)

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Progressive headache in young woman with elevated BMI (≈90% of IIH; Friedman 2013 PMID 23966248); Transient visual obscurations (≈70% in IIH; seconds-long greyout with postural change / Valsalva; Mollan 2018 PMID 29903905); Pulsatile tinnitus (≈60% in IIH; turbulent flow at transverse-sigmoid stenosis; Mollan 2018 PMID 29903905; Gurney 2020 PMID 32021528).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)** (neuro.idiopathic-intracranial-hypertension.v1).
Phenotype framing: CVST (separate engine; MRV-positive), CSF leak (orthostatic headache, low-pressure phenotype), pituitary mass, malignant hypertension, dural AVF, IIH-without-papilledema (rare), chronic migraine without papilledema (Friedman 2013 PMID 23966248; Mollan 2018 PMID 29903905)
Scope: Vision-threatening intracranial hypertension in a young woman with elevated BMI; pivot on headache + papilledema + normal neuro exam + normal imaging + raised LP opening pressure + normal CSF (Friedman 2013 PMID 23966248)

No severity triggers fired against current inputs.

Plan

Regimen axis: **IIH four-pillar treatment ladder — weight loss + carbonic-anhydrase inhibitor + topiramate adjunct + surgical rescue (Mollan 2018 PMID 29903905 + Wall IIHTT PMID 24756514 + Mollan IIH:WT 2021 PMID 33900360 + Abbott 2023 PMID 37813577 + Gurney 2020 PMID 32021528)** — step "Pillar 1 — Disease-modifying weight loss (Mollan IIH:WT 2021 PMID 33900360; Abbott 2023 PMID 37813577)".
1. lifestyle_weight_loss_multicomponent (lifestyle, first line) — Multicomponent lifestyle intervention (diet + activity + behaviour) — Abbott 2023 grade B for BMI<35 (PMID 37813577); 5-15% weight loss reduces ICP and headache disability (Markey 2015 PMID 26700907)
2. bariatric_surgery_referral (lifestyle, first line) — Bariatric surgery is superior to community weight management at lowering ICP and inducing remission (Mollan IIH:WT 2021 PMID 33900360 + 2022 substudy PMID 35790425); Abbott 2023 grade A for BMI≥35 (PMID 37813577)
3. liraglutide 0.6 mg SC daily, titrate to 3.0 mg SC daily over 5 weeks SC daily (GLP1_receptor_agonist, add on) — GLP-1 receptor agonists shown to reduce ICP and produce weight loss in IIH pilot data — emerging adjunct flagged in Mollan 2019 review (PMID 30865008); not yet AHA/UK consensus first-line

Setting playbook (outpatient) — Long-term IIH management — multicomponent weight loss + acetazolamide titration + serial ophthalmology + relapse surveillance + bariatric-surgery referral if BMI ≥35; PCOS/OSA co-management; contraception + pregnancy planning (Mollan 2018 PMID 29903905; Abbott 2023 PMID 37813577)
4. acetazolamide Maintain at lowest effective dose 500 mg-4 g/day divided; taper on sustained remission PO BID-QID — Established IIH on maintenance (Wall IIHTT 2014 (PMID 24756514))
5. topiramate 50-100 mg/day if headache-predominant PO daily-BID — Headache-predominant IIH not on bariatric path (Mollan 2018 (PMID 29903905))
6. liraglutide 0.6 → 3.0 mg SC daily over 5 weeks SC daily — Adjunctive pharmacologic weight loss in BMI ≥30 patient unable to access bariatric surgery (Emerging GLP-1RA evidence (Mitchell 2019 PMID 30865008))

Non-pharmacologic actions:
- Multicomponent weight-loss programme (diet + activity + behaviour) — Abbott 2023 grade B for BMI<35 (PMID 37813577)
- Bariatric surgery referral for BMI ≥35 — Abbott 2023 grade A; Mollan IIH:WT 2021 RCT (PMID 33900360 + PMID 35790425)
- PCOS / OSA co-management (Markey 2015 PMID 26700907)
- Patient education + IIH-UK support group referral (Mollan 2018 PMID 29903905)
- Driving restrictions per jurisdictional rules if vision-impaired

AVOID / contraindication checks:
- No_topiramate_in_pregnancy_planned_pregnancy_cleft_palate_risk (Mollan 2018 PMID 29903905)
- No_acetazolamide_if_sulfa_severe_allergy_or_metabolic_acidosis_HCO3<18 (Wall IIHTT 2014 PMID 24756514)
- Avoid_acetazolamide_in_pregnancy_first_trimester (FDA category C; pragmatic avoidance; Mollan 2018 PMID 29903905)
- No_steroids_for_IIH_maintenance_rebound_on_taper (Mollan 2018 PMID 29903905)
- No_repeat_LP_as_durable_therapy_short_lived_only (Mollan 2018 PMID 29903905)
- Discontinue_tetracyclines_retinoids_cyclosporine_lithium_GH_at_diagnosis (Friedman 2013 PMID 23966248)

Monitoring

Regimen monitoring:
- ophthalmology HVF and OCT at diagnosis then 1-2wk acute then monthly until stable (Mollan 2018 PMID 29903905)
- serial weight BMI at every visit (Mollan IIH:WT 2021 PMID 33900360)
- serial HCO3 K creatinine on acetazolamide or topiramate (Wall IIHTT 2014 PMID 24756514)
- lifelong relapse surveillance with weight regain (Abbott 2023 PMID 37813577)
- pregnancy specific monthly ophtho in pregnancy IIH (Mollan 2018 PMID 29903905)

Setting (outpatient) monitoring:
- Clinic visits monthly × 3 acute → q3 mo until remission → q6 mo lifelong (Mollan 2018 PMID 29903905)
- HVF + OCT cadence per severity (Mollan 2018 PMID 29903905)
- Weight at every visit (Abbott 2023 PMID 37813577)

Follow-up plan: Lifelong relapse surveillance — recurrence with weight regain is common; reinforce weight-maintenance + bariatric-surgery referral if BMI ≥35 sustained; PCOS / OSA co-management; contraception counselling (avoid GH, retinoids, tetracyclines lifelong); pregnancy planning + monitoring algorithm (Abbott 2023 PMID 37813577; Mollan 2018 PMID 29903905)
- Close-out criterion: Long-term plan + recurrence-trigger education delivered

Monitoring phase: Serial ophthalmology (HVF + OCT) at 1-2 wk acute → monthly until stable → 3-6 monthly long-term; serial weight + BMI; serial HCO3 / K on acetazolamide; pregnancy-specific monthly visits (Mollan 2018 PMID 29903905; Wall IIHTT 2014 PMID 24756514)

Disposition

Current setting: outpatient — Long-term IIH management — multicomponent weight loss + acetazolamide titration + serial ophthalmology + relapse surveillance + bariatric-surgery referral if BMI ≥35; PCOS/OSA co-management; contraception + pregnancy planning (Mollan 2018 PMID 29903905; Abbott 2023 PMID 37813577)

Disposition criteria:
- Remission criteria — papilledema resolved + HVF stable × 6-12 mo on minimal therapy → consider taper (Mollan 2018 PMID 29903905)
- Lifelong surveillance at q6-12 mo even in remission (Abbott 2023 PMID 37813577)

Escalation triggers (move to higher acuity):
- New field loss OR Frisén progression → admit + surgical evaluation (Mollan 2018 PMID 29903905)
- Weight regain > 5% with symptom recurrence → bariatric referral (Abbott 2023 PMID 37813577)
- Pregnancy planning → MFM + ophthalmology MDT and stop topiramate + plan ACZ-cautious or hold (Mollan 2018 PMID 29903905)

Patient Action Plan

**IIH vision-protection + weight-loss action plan**
Personalised values: current_medications, next_ophthalmology_date, bmi, pregnancy_status, bariatric_referral_status.

**Doing well — stable IIH** (green):
Triggers:
- no_new_vision_symptoms
- stable_headache_burden
- on_target_with_weight_loss
- on_track_with_acetazolamide
Actions:
- Continue acetazolamide / topiramate as prescribed
- Keep ophthalmology + neurology + bariatric appointments
- Maintain weight-loss programme
- Avoid IIH-trigger drugs (tetracyclines, retinoids, lithium, GH) lifelong

**Caution — call IIH clinic same day** (yellow):
Triggers:
- new_intermittent_visual_obscurations
- worsening_daily_headache
- weight_regain_>5pct
- paresthesias_or_GI_symptoms_on_acetazolamide
- planned_pregnancy_or_positive_test
Actions:
- Call IIH clinic / neuro-ophthalmology same day
- Do NOT stop acetazolamide without instruction
- If pregnancy positive — stop topiramate immediately + contact clinic
- Bring medication list to clinic call

**Emergency — call 911 / go to ED** (red):
Triggers:
- sudden_or_progressive_vision_loss
- thunderclap_headache
- new_focal_neurological_deficit
- loss_of_consciousness
- severe_diplopia
Actions:
- Call 911 / go to nearest ED
- Tell ED you have IIH on ACZ ± topiramate
- Bring medication list and any ophthalmology summary
Contact provider when:
- Any red-zone trigger
- After any ED visit so IIH team is updated

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Vision loss progressing over <4 weeks from onset (Mollan 2018 PMID 29903905)
- [SEVERE] Frisén grade 4-5 OR OCT RNFL >300 µm at presentation (Wall IIHTT 2014 PMID 24756514; Mollan 2018 PMID 29903905)
- [SEVERE] Worsening HVF perimetric mean deviation on optimal medical therapy (Wall IIHTT 2014 PMID 24756514)

Citations

- Mollan IIH consensus management guidelines (JNNP 2018 PMID 29903905) + Friedman 2013 revised diagnostic criteria (Neurology 2013 PMID 23966248) + Wall IIHTT (JAMA 2014 PMID 24756514) + Mollan IIH:WT (JAMA Neurol 2021 PMID 33900360) + Abbott weight management systematic review (Neurology 2023 PMID 37813577) [PMID:23966248](https://pubmed.ncbi.nlm.nih.gov/23966248/)
- Cited evidence (PMID 29903905) [PMID:29903905](https://pubmed.ncbi.nlm.nih.gov/29903905/)
- Cited evidence (PMID 30154235) [PMID:30154235](https://pubmed.ncbi.nlm.nih.gov/30154235/)
- Cited evidence (PMID 24756514) [PMID:24756514](https://pubmed.ncbi.nlm.nih.gov/24756514/)
- Cited evidence (PMID 33900360) [PMID:33900360](https://pubmed.ncbi.nlm.nih.gov/33900360/)

Last reconciled with current guidelines: 2026-05-26.
References
  • Mollan IIH consensus management guidelines (JNNP 2018 PMID 29903905) + Friedman 2013 revised diagnostic criteria (Neurology 2013 PMID 23966248) + Wall IIHTT (JAMA 2014 PMID 24756514) + Mollan IIH:WT (JAMA Neurol 2021 PMID 33900360) + Abbott weight management systematic review (Neurology 2023 PMID 37813577) — PMID:23966248
  • Cited evidence (PMID 29903905) — PMID:29903905
  • Cited evidence (PMID 30154235) — PMID:30154235
  • Cited evidence (PMID 24756514) — PMID:24756514
  • Cited evidence (PMID 33900360) — PMID:33900360