Idiopathic Intracranial Hypertension: A Venous Disease?
Idiopathic intracranial hypertension (IIH) is a condition characterized by a constellation of symptoms including headache, visual disturbance, tinnitus, and papilledema that affect primarily obese/young female. The pathophysiologic hallmark of the disease is a chronic elevation of intracranial pressure (opening pressure on lumbar puncture >250 cm H2O). Despite the significant morbidity associated with this condition (vision loss and debilitating headaches), the exact mechanisms leading high intracranial pressure is not known. It has been purported that cerebral venous stenosis (CVS) may play a role in the pathogenesis of idiopathic intracranial hypertension. In this chapter, we examine the evidence linking cerebral venous stenosis to IIH. From an epidemiological perspective, CVS is up to 9 times more prevalent among patients with IIH compared to their counterparts, and the cerebral venous pressure gradient across the stenotic segment by venographic manometry is higher among patients with IIH. Pathophysiological evidence for an association between CVS and IIH suggest that at least in some cases, variations in the caliber of the cerebral vein is associated with a change in cerebrospinal fluid pressure; an observation that is supported by mathematical models. In the absence of randomized clinical trials, the best evidence supporting CVS stenting are primarily provided by meta-analyses of individual studies that report a clinical benefit of the procedure albeit several shortfalls. In light of the suggested association between cerebral transverse sinus stenosis/hypoplasia and certain IIH cases, future research would need to focus on defining the clinical and radiological profile of individuals who will best benefit from CVS stenting. It is also expected that ongoing clinical trials shed more light on the association between CVS and IIH and refine the therapeutic potentials of stenting.
KeywordsEpidemiology Treatment Stenting Idiopathic intracranial hypertension Cerebral venous stenosis Pseudotumor cerebri
We would like to thank Drs. Samir Belagaje and Saher Khalid for their generous comments on this manuscript. Dr. Feng would like to acknowledge the grant supports from National Institute of Health (P20GM109040 and HD086844), American Heart Association (14SDG1829003) and South Carolina Clinical & Translational Research Institute (UL1 TR001450).
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