Idiopathic Intracranial Hypertension with and Without Papilledema: A Comparative Cohort Study.

Background: Idiopathic intracranial hypertension without papilledema (IIHWOP) is increasingly recognized, but its clinical characteristics and treatment-related outcomes remain insufficiently defined. This study aimed to compare patients with idiopathic intracranial hypertension (IIH) with and without papilledema. Methods: This retrospective observational cohort study included adult patients diagnosed with IIH at a tertiary neurology and referral center. Demographic, clinical, neuro-ophthalmologic, radiological, lumbar puncture, and treatment-related characteristics were compared according to papilledema status. Results: Among 123 patients with IIH, 83 (67.5%) had papilledema, and 40 (32.5%) had IIHWOP. Age, sex distribution, body mass index, lumbar puncture opening pressure, and most neuroimaging findings were similar between groups. In exploratory between-group analyses, photophobia [35/40 (87.5%) vs. 55/83 (66.3%), p = 0.023], phonophobia [35/40 (87.5%) vs. 56/83 (67.5%), p = 0.031], and nausea/vomiting [20/40 (50.0%) vs. 17/83 (20.5%), p = 0.002] were more frequent among patients with IIHWOP than among those with papilledema. Diabetes mellitus was also more frequent in the IIHWOP group [8/40 (20.0%) vs. 5/83 (6.0%), p = 0.040]. Treatment persistence did not differ significantly between groups (log-rank p = 0.604). In multivariable analysis, papilledema was associated with higher odds of failure to achieve a complete treatment response, whereas higher lumbar puncture opening pressure was associated with lower odds of treatment nonresponse. Conclusions: Exploratory analyses suggested that patients with IIHWOP may exhibit a different clinical presentation characterized by more prominent migraine-like symptoms. However, these exploratory observations require confirmation in prospective studies.