Feasibility and usefulness of ultrasonography in idiopathic intracranial hypertension or secondary intracranial hypertension.

BACKGROUND: Transorbital sonography (TOS) has been proven to be able to non-invasively detect elevated intracranial pressure. In this condition TOS shows an increase in optic nerve sheath diameter (ONSD). It has been suggested that internal jugular vein valve insufficiency (IJVVI) may represent a factor contributing to the pathogenesis of idiopathic intracranial hypertension (IIH). The aim of this study was to investigate whether patients with IIH or secondary IH have higher ONSD values and higher frequency of IJVVI compared to subjects without IH.

METHODS: Twenty-one patients with newly diagnosed IIH or secondary IH were prospectively evaluated and compared with 21 age, gender and BMI-matched controls. Experienced vascular sonographers used B-mode TOS to evaluate ONSD, optic nerve diameter (OND) and IJVVI. CSF opening pressures were also measured.

RESULTS: ONSD values were significantly higher in patients (6.50 ± 0.67) than controls (5.73 ± 0.66; p < 0.0001). No differences were found in OND values between patients (2.99 ± 0.26) and controls (2.93 ± 0.41; p = 0.574). No correlation was demonstrated between ONSD and CSF opening pressure (r = 0,086) (p = 0.73). No difference in frequency of IJVVI between patients (11/42 valves, 26 %) and controls (9/42, 21 %) was observed (p = 0.777).

CONCLUSIONS: Increased ONSD values detected by TOS support the diagnosis of IH. Our results do not support the hypothesis of a venous congestion as a potential factor contributing to the pathogenesis of IIH.

TRIAL REGISTRATION: Not applicable. Observational, non-interventional study.