Increased brain volume in idiopathic intracranial hypertension: Association with intracranial pressure and papilledema severity.

BACKGROUND

The pathophysiology responsible for IIH and raised intracranial pressure remains incompletely understood. It is similarly unclear how brain volume in IIH might contribute to increased intracranial pressure and/or papilledema.

METHODS

IIH patients and a set of age-matched controls were retrospectively identified from our healthcare institution. Volumetric quantitative MRI analysis was used to investigate differences in total brain volume, gray matter (GM), and white matter (WM), which were all normalized to account for head size. Associations between parenchymal volumes with opening pressure were assessed via multiple linear regression accounting for age, sex, and BMI.

RESULTS

In total, 84 IIH patients (87 % female, mean age 29.8 years) were compared to 15 age-matched controls. Overall, patients with IIH were found to have higher total normalized brain volume compared to controls (p = 0.015), and higher GM/WM volumes. Increasing GM volume was significantly associated with increasing opening pressure (p = 0.031, R = 0.37), however total brain and WM volumes were not. Likewise, IIH patients with severe papilledema had higher GM volume compared to those with mild papilledema (p = 0.026).

CONCLUSION

These preliminary findings suggest that patients with IIH possess larger brains, of unclear mechanism. Likewise, higher gray matter volume might contribute to the development of increased intracranial pressure and papilledema severity.