Focal stenosis of the sigmoid sinus causing intracranial venous hypertension: Case report, endovascular management, and review of the literature

Risk factors for the development of secondary intracranial hypertension in acute cerebral venous thrombosis

PURPOSE

Intracranial hypertension (IH) can complicate cerebral venous thrombosis (CVT), potentially causing permanent visual loss. Current knowledge on risk factors for the development of IH following CVT is scarce. We applied a compound classifier (CSF opening pressure > 25 cmH₂O, papilledema, or optic disc protrusion on MRI) as a surrogate for IH and studied the predictive value of thrombus location, the number of thrombosed segments, and thrombus volume.

METHODS

We prospectively included 26 patients with acute CVT and complete MRI data. IH was defined by CSF opening pressure > 25 cmH₂O, papilledema, or optic disc protrusion on MRI. Using high-resolution contrast-enhanced venography, we determined the thrombus location, number of thrombosed segments, and thrombus volume. We analyzed their association with IH by logistic regression, their predictive power by the area under the receiver operating characteristic curve, and their association with CSF opening pressure by linear regression.

RESULTS

IH occurred in 46% of CVT patients and was associated with higher thrombus volume (AUC 0.759, p = 0.025) and superior sagittal sinus thrombosis both alone (OR 2.086, p = 0.049) and combined with transverse sinus thrombosis (OR 2.014, p = 0.028). Effects in patients presenting CSF opening pressure > 25 cm H₂O and the compound classifier were consistent. Thrombus volume > 4 ml was the single most important predictor of higher CSF opening pressure (ß = 0.566, p = 0.035), increasing IH risk.

CONCLUSION

Larger thrombus volume, dominant transverse sinus occlusion, and extensive superior sagittal combined with transverse sinus thrombosis were associated with IH. Thrombus volumetry might identify patients at risk for IH and direct further clinical evaluation.

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.

Stenosis Before Thrombosis: Intracranial Hypertension from Jugular Foramen Stenosis Secondary to Renal Osteodystrophy

BACKGROUND

Venous outflow obstructions are rare anatomic findings that can appear with symptoms of elevated intracranial pressure, including headache and vision loss, and can be mistaken for more common diagnoses, such as idiopathic intracranial hypertension (IIH) or cerebral venous sinus thrombosis (CVST). Although venous outflow obstructions have been reported in rare bone dysplasias and congenital abnormalities, to date they have not been reported in renal osteodystrophy (ROD), a relatively common disorder seen in patients with chronic kidney disease.

CASE DESCRIPTION

In this case, the authors describe a patient with marked intracranial hypertension from jugular foramen stenosis secondary to ROD. After diagnosis by CT and magnetic resonance venography, catheter venography confirmed an osseus band around the left jugular bulb, and a 40-mm Hg pressure gradient across the stenotic foramen. The patient subsequently underwent ventriculoperitoneal shunting and optic nerve sheath fenestration with symptom improvement. The postoperative course was significant for development of CVST, necessitating treatment.

CONCLUSIONS

This report reviews the presentation, pathology, and neurosurgical treatment of patients with ROD and venous outflow obstructions, and explores the differential diagnoses of outflow obstructions, IIH, and CVST. To our knowledge, this is the first report of intracranial hypertension from jugular foramen stenosis secondary to renal osteodystrophy.