Cerebral Venous Outflow Implications in Idiopathic Intracranial Hypertension-From Physiopathology to Treatment

Abstract

In this review, we provide an update on the pathogenesis, diagnosis, and management of adults with idiopathic intracranial hypertension (IIH) and implications of the cerebral venous system, highlighting the progress made during the past decade with regard to mechanisms of the venous outflow pathway and its connection with the cerebral glymphatic and lymphatic network in genesis of IIH. Early diagnosis and treatment are crucial for favorable visual outcomes and to avoid vision loss, but there is also a risk of overdiagnosis and misdiagnosis in many patients with IIH. We also present details about treatment of intracranial hypertension, which is possible in most cases with a combination of weight loss and drug treatments, but also in selected cases with surgical interventions such as optic nerve sheath fenestration, cerebral spinal fluid (CSF) diversion, or dural venous sinus stenting for some patients with cerebral venous sinus stenosis, after careful analysis of mechanisms of intracranial hypertension, patient clinical profile, and method risks.

Keywords: cerebral venous sinus stenosis; cerebral venous sinus stenting; idiopathic intracranial hypertension; magnetic resonance venography; optical nerve sheath fenestration; pseudotumor cerebri.

Figure 1

MRI changes in patients with IIH. (A) Partial empty sella, T1 weighted MRI. (B) Distention of the optic nerve sheath with enlarged cerebrospinal fluid (CSF) spaces surrounding the optic nerve in T2 weighted MRI with fat suppressed sequence (arrow), empty sella also visible (hyperintense signal). (C) Noncontrast axial T2 scan reveals that the right optic nerve cannot be entirely displayed along a single plane because the signal of orbital fat obscures the mid-portion of the nerve (“smear sign”). (D) Coronal T2 weighted MRI—distention of the optic nerve sheath with enlarged hyperintense CSF ring. (E) Axial T2 scan reveals meningoceles involving both of Meckel caves (arrowheads).