I came across this interesting case study of a patient who developped blindness and optic nerve edema two years after an arterio-venous graft/shunt was placed. This shunt was between the right brachial atery and internal jugular vein. A shunt like this increases pressure in the venous system as it it directly connected to the high pressure arterial system. Symptoms resolved when this graft was occluded. There are several other similar case studies in the litterature.
I don't know if this article has been previously mentioned on this site, but it provides evidence that malfunctioning venous outflow from the CNS can result in CNS pathology.
"Cerebral venous hypertension and blindness: A reversible complication Presented at the Eighteenth Annual Meeting of the Eastern Vascular Society, Philadelphia, PA, May 1, 2004.
Salvador A. Cuadra MDa, b, Frank T. Padberg MDa, b, , Roger E. Turbin MDa, d, Jeffrey Farkas MDa, c and Larry P. Frohman MDa, e
aUniversity of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ
bDivision of Vascular Surgery, Department of Surgery, Newark, NJ
cDepartment of Radiology, Newark, NJ
dInstitute of Ophthalmology and Visual Science, Newark, NJ
eInstitute of Ophthalmology and Visual Science and Neurology and Neurosciences, Newark, NJ
Received 2 March 2005; accepted 28 May 2005. Available online 19 October 2005.
A 57-year-old woman developed blindness during treatment for sarcoidosis-induced end-stage renal disease. An initial renal transplantation failed, and hemoaccess was maintained with multiple central catheters and upper extremity prosthetic arteriovenous grafts. A successful second transplantation eliminated her need for hemodialysis, but a right brachial to internal jugular graft remained patent. Progressive visual loss 2 years after transplantation prompted ophthalmic evaluation which initially revealed unilateral left optic nerve edema and visual loss, ultimately worsening over several months to no light perception in the left eye, 20/60 vision in the right eye, and bilateral papilledema. Arteriography demonstrated cerebral venous hypertension attributed to the functioning hemoaccess graft. Permanent graft occlusion normalized the papilledema, and visual field defects in the right eye and visual acuity returned to 20/20 in the right eye."