Abstract

Despite increased recognition of the contribution of venous outflow to intracranial pressure (ICP),¹ there has been limited attention to venous hypertension as a cause of secondary intracranial hypertension, especially in children. Interventions for venous hypertension focus on addressing the underlying etiology, and can vary as widely as the underlying causes. We present a series of nine cases of pediatric venous hypertension treated at our institution, with an emphasis on the causes and successful treatment modalities.

To understand the contribution of venous outflow to ICP, one needs to consider its contribution to intracranial contents. Intracranial blood volume as a whole measures 100–130 ml, compared to 75 ml of intracranial cerebrospinal fluid (CSF), which dominates ICP management. Moreover, 40% of the intracranial blood volume is found in the venous circulation, while only 15% is in the arterial circulation, another target in intracranial physiologic optimization. Additionally, if cerebral venous outflow fails to match arterial inflow, the resulting changes in intracranial contents can further predispose the patient to intracranial hypertension.¹

Consideration of venous hypertension has been particularly limited in pediatrics. Although venous sinus thrombosis and post-traumatic occlusion have recently received dedicated attention in pediatrics,^{2 3} there have only been isolated reports of other causes of venous hypertension in children, such as venous sinus stenosis,⁴ extramural venous sinus obstruction,^{5 6} direct arteriovenous shunting as seen in dural arteriovenous fistulas,⁷ as well as jugular foramen stenosis in achondroplasia⁸ and craniosynostosis.⁹

We present a compendium of pediatric cases of venous hypertension treated at our institution, typically diagnosed clinically and on cerebral angiography. After obtaining IRB approval, we reviewed our database of pediatric imaging studies for evidence of venous hypertension, specifically looking for findings of venous outflow stenoses or occlusion, and the presence of ‘pseudophlebitic’ pattern with tortuous, ‘cork-screw’ cortical veins. We also reviewed available clinical measures of ICP, such as invasive monitoring, optical coherence tomography, opening pressure, and optic nerve sheath diameter. We reviewed cross-sectional imaging for ventriculomegaly, dilated or tortuous optic nerve sheaths, and the presence of empty sella. The different treatment modalities were assessed using chart review.

The identified cases fall into two categories: cases of venous outflow impairment, with treatment focused on relief of obstruction; and cases of arteriovenous shunting, requiring embolization. Use of CSF diversion and medical management is also addressed. Causes of venous outflow impairment in our case series include: transverse sinus stenosis, cervical and jugular venous stenosis, compression of jugular veins at the jugular foramina in the setting of achondroplasia, jugular venous compression by the styloid process, and a restrictive small vessel venopathy. Cases of arteriovenous shunting include: direct arterio-venous fistula in the setting of hereditary hemorrhagic telangiectasia, congenital arteriovenous fistula presenting with an acquired Chiari I malformation, pial and retinal arteriovenous malformation presenting with subarachnoid hemorrhage in the setting of Wyburn-Mason syndrome, and a holohemispheric arteriovenous malformation and/or flow-related arteriopathy with extensive shunting. By reviewing these cases, and the relative success of interventions undertaken, we aim to present a guide to approaching the pediatric venous hypertension patient.