E-004 intracranial venous hypertension due to severe focal web-like stenosis of the sigmoid sinus associated with contralateral sinus hypoplasia: a new diagnostic entity?

Abstract

Purpose Regardless of the underlying pathology, elevated intracranial pressure is the end-point of any impairment in either CSF absorption (arachnoid vili) or intracranial venous drainage. Intracranial venous hypertension (ICVH) is an important vascular cause of intracranial hypertension (and its subsequent sequelae) which often has been ignored due to excessive attention to the arterial system and specifically AV shunts. Various anatomical and pathological entities have been described to cause ICVH. For the second time, we present a unique case of severe focal web-like stenosis in the distal sigmoid sinus associated with concurrent hypoplasia of the contralateral transverse sinus (TS) causing a significant pressure gradient and intracranial hypertension. Case Report A 31-month-old boy presented with the chief complaint of progressive vision loss and frequent falls. Physical examination was positive for prominent periorbital veins and decreased bilateral visual acuity. Fundoscopy revealed extensive fluid around the optic nerve and inappreciable cup-to-disc ratio with blurring of the disc margins bilaterally consistent with papilledema. Image Findings MR imaging examination revealed mild to moderate lateral and third ventriculomegaly associated with an empty sella, consistent with increased intracranial pressure. No intracranial/parenchymal, extra-axial mass effect or optic nerve lesion was identified (Figure 1A). DSA demonstrated congenitally hypoplastic right transverse and sigmoid sinuses extending into a small right internal jugular vein. A severe focal web-like stenosis of the distal dominant left sigmoid sinus was observed (Figure 1B). Direct pressure measurement in the dural venous sinuses revealed abnormally elevated pressures proximal to the web-like stenosis and a significant gradient (20 mm Hg) across the stenosis: proximal left internal jugular vein: 12 mmHg, left TS: 40 mmHg, and distal sigmoid sinus: 32 mmHg. Using over-the-wire technique, a self-expanding nitinol stent was placed successfully across the web-like stenosis and sequential overlapping balloon angioplasty was performed successfully. There was immediate improvement in the appearance of the stenosis with a mild residual stenosis and the pressure gradient was immediately and dramatically reduced (Figures 1C and 1D). Summary Isolated venous outflow obstruction leading to intracranial hypertension has been reported before;1 however, the presented case is the second case of a unique morphological venous anomaly, namely a severe focal web-like stenosis occurring in the dominant sigmoid sinus associated with concurrent hypoplasia of the contralateral TS leading to significant pressure gradient and ICVH. Reference Soltanolkotabi M, Rahimi S, Hurley MC, et al. Endovascular correction of an infantile intracranial venous outflow obstruction. Journal of neurosurgery Pediatrics 2013;12:660–663 Disclosures A. Honarmand: None. M. Hurley: None. F. Syed: None. S. Ansari: None. A. Shaibani: None.