Cases of visual impairment caused by cerebral venous sinus occlusion-induced intracranial hypertension in the absence of headache

BACKGROUND: Cerebral venous sinus thrombosis or stenosis (here collectively referred to as cerebral venous sinus occlusion, CVSO) can cause chronically-elevated intracranial pressure (ICP). Patients may have no neurological symptoms other than visual impairment, secondary to bilateral papilledema. Correctly recognizing these conditions, through proper ophthalmological examination and brain imaging, is very important to avoid delayed diagnosis and treatment. CASE PRESENTATION: We report a case series of 3 patients with chronic CVSO, who were admitted to an ophthalmological department in Chongqing, China, from 2015 March to 2017 February. All patients presented with decreased vision and bilateral papilledema, but had no headache or other neurological symptoms. The visual fields of all patients were impaired. Flash visual evoked potentials (VEPs) in two patients showed essentially normal peak time of P2 wave, and pattern VEPs in one patient displayed decreased P100 amplitude in one eye, while a normal P100 wave in the other eye. In all patients, lumbar puncture (LP) revealed significantly elevated ICP. And magnetic resonance venography (MRV) demonstrated cerebral venous sinus abnormalities in every patient: one right sigmoid sinus thrombosis, one superior sagittal sinus thrombosis, and one right transverse sinus stenosis. CONCLUSIONS: CVSO can cause chronically-elevated ICP, leading to bilateral papilledema and visual impairment. A considerable amount of patients have no apparent neurological symptoms other than visual loss. Unlike other optic nerve lesions, such as neuritis or ischemic optic neuropathy, the optic disc edema in CVSO is usually bilateral, the flash or pattern VEP is often normal or only mildly affected, and patients are often not sensitive to steroid therapy. CVSO should be suspected in such patients when unenhanced brain imaging is normal. Further investigations, such as LP and contrast-enhanced imaging (MRV and digital subtraction angiography), should be performed to diagnose or exclude CVSO.