Sonographic assessment of optic nerve and ophthalmic vessels in patients with idiopathic intracranial hypertension

Background: Early diagnosis and proper monitoring of intracranial pressure (ICP) in idiopathic intracranial hypertension (IIH) could reduce morbidity.

Objectives: The objective was to explore and monitor reflection of raised ICP in IIH on optic nerve sheath diameter (ONSD), papillary height and ophthalmic vessels hemodynamics, using transorbital sonography (TOS).

Methods: The study included 24 IIH patients and 30 controls. Patients were compared to controls (phase I) then reassessed twice; 1 week and 4 weeks later (phase II). Both groups underwent clinical evaluation and TOS to measure ONSD, papillary elevation, and color Doppler indices of the ophthalmic vessels. Patients underwent lumbar puncture (LP) to measure cerebrospinal fluid (CSF) pressure.

Results: ONSD was significantly higher in patients compared to controls (p < 0.001). The cut-off value was 6.2 mm. Papillary elevation (p = 0.006) and ONSD (p = 0.006) were significantly reduced 4 weeks following LP. Baseline color Doppler indices of the ophthalmic vessels were comparable between both groups and the changes observed during the follow-up visits in the patients were insignificant.

Conclusion: Reflected ICP changes on ONSD and papilla, measured by TOS, could be a valuable noninvasive additional tool to diagnose and monitor IIH patients. IIH insignificantly influences ophthalmic vessels hemodynamics.

Abbreviation BMI: Body mass index. CSF: Cerebrospinal fluid. EDV: End diastolic velocity. ICP: Intracranial pressure. IH:intracranial hypertension. IIH: Idiopathic intracranial hypertension. LP: Lumbar puncture. MI: Mechanical index. MRI: Magnetic resonance imaging. MRV: Magnetic resonance venography. OA: Ophthalmic artery OND: Optic nerve diameter. ONSD: Optic nerve sheath diameter. OV: Ophthalmic vein. PIs: Pulsatility indices. PSV: Peak systolic velocity. ROC: Receiver operator characteristic. TOS: Trans-orbital sonography.