Sonographic and ophthalmic assessment of optic nerve in patients with idiopathic intracranial hypertension: A longitudinal study

Abstract

Background: To assess the validity of neurosonological parameters (transorbital sonography (TOS)) for detection and monitoring of patients with idiopathic intracranial hypertension (IIH).

Methods: Prospective, single-center, case-controlled study in 25 patients with IIH and 19 controls. Visual parameters of papilledema, visual acuity, computerized static threshold perimetry, fundus examination, and neurosonological parameters of papilledema/optic disc elevation (ODE), optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) were recorded at baseline and only for patients with IIH again within 6 months.

Results: ONSD was significantly enlarged among individuals with IIH (6.2 ± 0.73 mm) compared to controls (4.99 ± 0.54 mm; p < 0.001). Bilateral ODE was found in 36/50 eyes in patients at their initial visit and in none of the controls. Re-evaluation 6 months later showed a significant reduction of ONSD (6.0 ± 0.7 mm; p = 0.024) and ODE (0.2 (0-1) mm; p ≤0.001). Best corrected visual acuity (BCVA) and square root of lost variance (sLV) remained stable. Headache intensity (Numeric rating scale, NRS) improved significantly p < 0.001. When compared to patients with first diagnosed IIH (n = 18), the subset of patients with preexisting IIH with acute relapse (n = 7) showed persistent but reduced levels of ICP increase. They also presented significant decrease of BVCA (p = 0.01) and mean defect (MD) (p = 0.012). Re-evaluation 6 months later showed significant change in ODE in both groups.

Conclusions: Our study confirmed that TOS and ophthalmological parameters are a valuable and non-invasive method to detect and monitor elevated ICP in IIH.

Keywords: Idiopathic intracranial hypertension; Neuro ophthalmological parameters.; Optic nerve sheath diameter; Papilledema.; Pseudotumor cerebri syndrome.; Transorbital sonography..