The clinical course and prognosis of incidental idiopathic intracranial hypertension (IIH) patients: the Ottawa experience

Theme: Neuro-ophthalmology
What: Neuro-ophthalmology
Part of: Neuro-ophthalmology I / Neuro-ophtalmolgie I
When: 6/1/2024, 11:15 AM - 12:45 PM
Where: Room | Salle 714 B

Abstract

Purpose: A subset of patients with IIH are diagnosed after incidental detection of optic nerve edema, and do not present because of symptoms of increased intracranial pressure (ICP). The objectives of this study were to compare the patients with incidental presentation of IIH (‘incidental IIH’) to those who present with symptoms of high ICP (‘symptomatic IIH’).

Study Design & Methods: This was a retrospective cross-sectional study of all patients who were referred to the Eye Institute in Ottawa, Canada between the dates of 31-Aug-2000 and 31-08-2022 for a possible diagnosis of IIH and who were later diagnosed with IIH/presumed IIH. Demographics, referring health professional, visual symptoms, systematic symptoms, visual signs, visual fields data, OCT data, (RNFL and ganglion cell complex), and neuroimaging findings were collected. Descriptive statistics were performed.

Results: One-hundred twenty-four patients were included: 24 had a diagnosis of incidental IIH while 100 were diagnosed with symptomatic IIH. The mean age in the incidental IIH group was 35.9 (standard deviation [SD], 4.5) and 30.3 in the symptomatic IIH group (SD, 2.3); this was a statistically significant difference (P<0.001). In the incidental IIH group, 0 (0%) were female, and in the symptomatic IIH group, 5 (5%) were female (P=0.263). In the incidental IIH group, 81.3% had no/mild grade of edema (between 0-2) in the worst eye, while in the symptomatic IIH group 61.6% had no/mild grade of edema (P=0.136).

Out of all incidental patients, 25% became symptomatic and the mean time to symptom onset was 15.1 months (SD, 10.4 months). Medical treatment was required in 50%, and no surgical treatment was required in any incidental IIH patient. In the symptomatic group, 80% of the patients required medical treatment (P=0.006 vs asymptomatic patients) and 9% of them required surgical intervention (P=0.13 versus asymptomatic patients).  Among incidental IIH patients, 50% received a lumbar puncture (LP) while 67.0% of the symptomatic patients received an LP (P=0.12). Among incidental IIH patients, the opening pressure of the LP was 28.95mmH₂O (SD, 6.36), while for symptomatic patients it was 29.745mmH₂O (SD, 10.38) (P=0.817). In terms of neuroimaging findings, 83.3% of patients with incidental IIH had features of high ICP on MRI, versus 82.0% of symptomatic IIH patients (P=0.880).

Conclusions: Patients with incidentally detected IIH are older than those who present because of symptoms of high ICP, however they have similar rates of optic disc edema, neuroimaging findings of high ICP, and high opening pressure on LP. Incidentally detected IIH patients are less likely to require medical treatment. Future work will compare visual outcomes between the groups.

Presenter(s)

Presenting Author: Matthew Quinn

Additional Author(s):

Danah Albreiki, University of Ottawa

Tara Gholamian, University of Ottawa

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