Idiopathic intracranial hypertension presenting with migraine phenotype is associated with unfavorable headache outcome

Abstract text (incl. figure legends and references)

Q: Migrainous headache is common in idiopathic intracranial hypertension (IIH), but its prognostic impact is unclear.Thus, we compared IIH with and without migraine phenotype.

M: We analyzed patients from the Vienna-Idiopathic-Intracranial-Hypertension (VIIH) database with definitive IIH according to Friedman criteria. We recorded CSF opening pressure and ophthalmologic findings and classified headache (HA) according to ICHD-3beta as migraine (IIH-MIG) or non-migrainous and absent (IIH-noMIG). Parameters were defined 12 months after IIH diagnosis comprising HA improvement (≥50% reduction of HA severity and/or frequency), freedom of HA (<1 HA day/month), impaired visual outcome (visual acuity ≥0.1 logMAR and/or mean deviation <-2.0 dB in static threshold perimetry) and visual worsening (≥0.2 logMAR and/or ≥2.0 dB worsening from baseline).

R: We included 97 patients (88.7% female, mean age 32.9 years, median BMI 32.0, 6.2% IIH-WOP, median CSF opening pressure 31cmH2O). IIH-MIG comprised 46.4% and IIH-noMIG 53.6% of the patients (11.3% tension-type HA, 25.8% unclassifiable HA, 16.5% no HA).
At baseline, IIH-MIG differed from IIH-noMIG with respect to monthly HA days (22 vs. 15, p=0.003) and HA severity (6.5 vs. 4.5; p<0.001). Age, BMI, CSF opening pressure, proportion of IIH-WOP, and visual acuity did not significantly differ between groups.
At follow-up, IIH-MIG compared to IIH-noMIG showed significantly lower rates for improvement and freedom of HA in all patients (66.7% vs 88.5%, p=0.009; 11.1% vs 42.3%, p=0.006) as well as in those with resolution of papilledema (n=40; 63.2% vs 95.2%, p=0.011; 5.3% vs 61.9%, p<0.001). Persistent visual impairment did not differ in the two groups (55.6% vs 57.7%), and visual worsening even tended to be less common in IIH-MIG than in IIH-noMIG (11.5% vs 24.4%, p=0.093).

C: In IIH, migrainous headache is associated with adverse outcomes for headache even when papilledema has resolved, but possibly with favorable visual outcome.