Abstract

Idiopathic Intracranial Hypertension (IIH) is a neurological condition characterized by increased intracranial pressure without any underlying intracranial pathology such as mass lesions in the brain or hydrocephalus. According to the Monroe-Kellie doctrine, there are three main components inside our rigid cranium, brain, blood, and CSF. Increase in volume of one component needs to be compensated by decrease in another component and/or increase in intracranial pressure. The most popular belief about the pathogenesis of IIH is that it is caused by venous sinus stenosis resulting in intracranial venous congestion and increase in ICP. With the recent discovery of another intracranial component, the glymphatic, the Monroe-Kellie doctrine needs to be revisited. In this review, we are providing evidence to define the relative importance of venous sinus stenosis and dysfunction of the glymphatic as the main pathogenetic mechanism for IIH. We also conclude that dysfunction of the glymphatic system is the main pathogenetic mechanism of IIH.

Keywords: Idiopathic intracranial hypertension (pseudotumor), Monroe-Kellie doctrine, Venous sinus stenosis, Cerebrospinal fluid, Interstitial fluid, Glymphatic

Abbreviations: IIH: Idiopathic Intracranial Hypertension; CSF: Cerebrospinal Fluid; ICP: Intracranial Pressure; ISF: Brain Interstitial Fluid; VR Space: Virchow-Robin Space