Clinical course of idiopathic intracranial hypertension with transverse sinus stenosis

Abstract

Objective: Transverse sinus stenosis (TSS) is common in idiopathic intracranial hypertension (IIH), but its effect on the course and outcome of IIH is unknown. We evaluated differences in TSS characteristics between patients with IIH with "good" vs. "poor" clinical courses.

Methods: All patients with IIH seen in our institution after September 2009 who underwent a high-quality standardized brain magnetic resonance venogram (MRV) were included. Patients were categorized as having a good or poor clinical course based on medical record review. The location and percent of each TSS were determined for each patient, and were correlated to the clinical outcome.

Results: We included 51 patients. Forty-six patients had bilateral TSS. The median average percent stenosis was 56%. Seventy-one percent of patients had stenoses >50%. Thirty-five of the 51 patients (69%) had no final visual field loss. Eight patients (16%) had a clinical course classified as poor. There was no difference in the average percent stenosis between those with good clinical courses vs those with poor courses (62% vs. 56%, p = 0.44). There was no difference in the percent stenosis based on the visual field grade (p = 0.38). CSF opening pressure was not associated with either location or degree of TSS.

Conclusion: TSS is common, if not universal, among patients with IIH, and is almost always bilateral. There is no correlation between the degree of TSS and the clinical course, including visual field loss, among patients with IIH, suggesting that clinical features, not the degree of TSS, should be used to determine management in IIH.

Figures

Figure 1. Reformatting and measurement of the degree of transverse sinus stenosis

The entire course of the transverse sinus in a single axial magnetic resonance venography image (A) is difficult to visualize, but with curved reformatting (B), the entire course of the transverse sinus is apparent. The percent stenosis was calculated by dividing the width of stenosis (C) by the width of the adjacent normal-appearing transverse sinus (D), yielding the percent stenosis.

Figure 2. Distribution of the average percent stenosis

The average percent stenosis ranged from 19% to 96% with a median of 56% (interquartile range 49%–65%). Seventy-one percent of patients had 50% or greater average percent stenosis.

Figure 3. Linear regression of average percent transverse sinus stenosis by CSF opening pressure

There was no relationship between the two (slope: −0.0027 percent stenosis/cm H2O, p = 0.28).

Figure 4. Distribution of the average percent stenosis and residual area by clinical course

Average percent stenosis (A) and residual area (B). There was no association with either transverse sinus stenosis (p = 0.44) or residual area (p = 0.27). IIH = idiopathic intracranial hypertension.

Figure 5. Distribution of average percent stenosis and residual area by visual field loss

Average percent stenosis (A) and residual area (B). Degree of visual field loss: 0 = none, 1 = mild/moderate, 2 = severe. There was no association with either transverse sinus stenosis (p = 0.98) or residual area (p = 0.81).