Idiopathic intracranial hypertension presenting with migraine phenotype is associated with unfavorable headache outcomes.

Objective: To assess the prognostic impact of migraine headache in idiopathic intracranial hypertension (IIH).

Background: Migraine headache is common in IIH, but it is unclear whether it has prognostic relevance.

Methods: We investigated patients with IIH from the Vienna-IIH-database and differentiated migraine (IIH-MIG) from non-migraine headache (IIH-nonMIG) and without headache (IIH-noHA). Using multivariable models, we analyzed the impact of IIH-MIG on headache and visual outcomes 12 months after diagnosis.

Results: Among 97 patients (89% female, mean [SD] age 32.9 [11.1] years, median body mass index 32.0 kg/m , median cerebrospinal fluid opening pressure 310 mm), 46% were assigned to IIH-MIG, 37% to IIH-nonMIG (11% tension-type, 26% unclassifiable), and 17% to IIH-noHA. Overall, headache improvement was achieved in 77% and freedom of headache in 28%. The IIH-MIG group showed significantly lower rates for headache improvement (67% vs. 89% in IIH-nonMIG, p = 0.019) and freedom of headache (11% vs. 33% in IIH-nonMIG and 63% in IIH-noHA, p = 0.015). These differences persisted when only analyzing patients with resolved papilledema at follow-up. In contrast, visual worsening was significantly less common in IIH-MIG (9% vs. 28% in IIH-nonMIG and 31% in IIH-noHA, p = 0.045). In multivariable models, IIH-MIG was associated with a significantly lower likelihood of achieving headache improvement (odds ratio [OR] 0.57, 95% confidence interval [CI] 0.40-0.78, p < 0.001) and freedom of headache (OR 0.29, 95% CI 0.12-0.46, p < 0.001), but also a lower risk for visual worsening (OR 0.26, 95% CI 0.04-0.82, p < 0.001).

Conclusions: In IIH, migraine headache is associated with unfavorable outcomes for headache, even when papilledema has resolved, and possibly favorable visual outcome.