Is higher choroid plexus 'load' an aetiologic factor in idiopathic intracranial hypertension? A clinico-imaging...

Idiopathic intracranial hypertension (IIH) is a condition of raised cerebrospinal fluid (CSF) pressure with normal ventricular size. Although the pathogenesis of IIH remains controversial, increased CSF formation may be important. We hypothesised that if increased CSF formation was an aetiologic factor, it might result in a macroscopic increase in size of the choroid plexus (CP).

We retrospectively studied 50 patients with IIH. Total size of the CP was estimated on computed tomography (CT) venograms from the sum of axial areas measured at three locations. Results were compared with the CP load of 50 matched controls on post-contrast head CTs. Evans Index was measured to exclude ventriculomegaly. Results were analysed using a Student's t test for independent samples (p < 0.05), and the effect of ICP was tested on the dependent variable (area of CP) using regression analysis.

There was no significant difference in the size of the CP glomus, total axial areas of the CP between IIH patients (183 mm(2)) and controls (178 mm(2)) and no correlation between the 'load' of CP and the degree of intracranial pressure (ICP) (R (2)< 0.02).

If increased CSF formation is an aetiologic factor in IIH, this is not reflected in a corresponding raised 'load' of CP.