Idiopathic Intracranial Hypertension Without Papilledema With Improvement in Visual Field Defect Following Optic Nerve Sheath Fenestration

Clinical Correspondence Section Editors: Robert Avery, DO Karl C. Golnik, MD Idiopathic Intracranial Hypertension Without Papilledema With Improvement in Visual Field Defect Following Optic Nerve Sheath Fenestration Stacy M. Scofield-Kaplan, MD, Kishan Patel, MD, Freddie Ray Jones Jr, MD, Robert Nick Hogan, MD, PhD Downloaded from http://journals.lww.com/jneuro-ophthalmology by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8KKGKV0Ymy+78= on 05/04/2022 A 32-year-old African American woman with a history of well-controlled hypertension, obesity, schizoaffective disorder, and a seizure disorder presented with significant headaches and progressive vision loss in both eyes worse in the few days before presentation. She endorsed significant headaches with associated tinnitus, whooshing sound in each ear, transient visual obscurations especially with bending over, and loss of peripheral vision. She was seen in the emergency room 2 weeks before with a normal computed tomography of the head without contrast and underwent a lumbar puncture in the sitting position with an opening pressure of 50 cm H2O. She was started on Diamox 125 mg 3-times daily, but she self-discontinued after 4 doses because of urinary retention and significant lower extremity swelling. On examination, the best-corrected visual acuity was 20/50 right eye and 20/60 left eye without a relative afferent pupillary defect. Her color vision was full in each eye with significant difficulty. Humphrey 30-2 perimetry revealed preservation of a very small central island in each eye (Fig. 1A, B). To deem if there was a reliable physiologic component, confrontation fields at multiple distances and visual acuity using multiple modalities were used, none of which suggested a nonphysiologic defect. The extraocular movements were full without slowing of saccades. The slit-lamp examination was unremarkable, and the funduscopic examination revealed a cup–to-disc of 0.4 in each optic nerve with sharp margins and no spontaneous venous pulsations. There was no pallor, optic nerve swelling, or evidence of a high-water mark (Fig. 2). An OCT of the optic nerve retinal nerve fiber layer (RNFL) revealed central thickness of 94 on the right and 96 on the left without any focal thinning. Laboratory evaluation included a negative FTAAbs, ACE, lysozyme, and lyme test with a low lithium level. Her Quantiferon gold test was indeterminate, but the chest Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas. The authors report no conflicts of interest. Address correspondence to R. Nick Hogan, MD, PhD, Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390; E-mail: Nick.Hogan@utsouthwestern. edu Scofield-Kaplan et al: J Neuro-Ophthalmol 2021; 41: e31-e33 x-ray was unremarkable. Magnetic resonance imaging (MRI) of the brain and orbits with gadolinium revealed mild prominence and dilation of the optic nerve sheaths bilaterally without any enhancement of the optic nerves and mild globe flattening on the left side. There was mild prominence of the Meckel’s cave bilaterally with no expansion or flattening of the pituitary along the floor of the sella turcica. An MRV of the head revealed a hypoplastic left transverse sinus without evidence of thrombosis. Lumbar puncture by interventional radiology in the left anterior oblique position was 30 cm H2O with normal cerebrospinal fluid (CSF) studies including cytology. She reported immediate relief of her headache after the lumbar puncture. She was started on Diamox and uptitrated to 1 g twice a day but again developed significant urinary retention requiring straight catheterization along with blisters and an oral rash. She had a repeat lumbar puncture with interventional radiology in the left anterior oblique position with an opening pressure of 30 and normal CSF studies. Given the significant visual field loss and inability to tolerate Diamox, we offered an optic nerve sheath fenestration (ONSF), which we discussed (given the lack of optic nerve swelling) may not improve her vision, but she agreed to proceed. She underwent an ONSF on the right followed by the left side 1 week later. Intraoperatively, she had enlargement of the retrobulbar optic nerve sheath with significant fluid flow or “gush” on each side. After the ONSF, she reported subjective improvement in vision with improvement in the central island to approximately 10° in each eye (Fig. 1C, D). She subsequently underwent a cerebral angiogram, which revealed the previously described hypoplastic left transverse sinus and also a focal stenosis of 75% at the junction of the right transverse and sigmoid sinus with an 11 mm Hg intraluminal pressure gradient. She then underwent stenting of the right transverse-sigmoid sinus 1 month after her ONSF procedures without improvement in headaches. Six months after ONSF, her vision had improved to 20/30 in each eye with improvement in the central island on visual field to approximately 15–20° in each eye (Fig. 1E, F). At this time, she had full color vision in each eye, the presence of spontaneous venous pulsations, no optic nerve edema, no optic nerve pallor, and no high water e31 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 1. Humphrey visual field 30-2 using a white stimulus III in the right and left eyes at diagnosis (A, B), 2 weeks after ONSF in each eye (C, D) and 6 months after ONSF in each eye (E, F). In (A), the mean deviation (MD) was 232.52 with 1/14 fixation losses (FL), 9% false positives (FP), and 0% false negatives (FN). In (B), the MD was 233.19 with 1/13 FL, 9% FP, and 0% FN. In (C), the MD was 229.11 with 0/15 FL, 1% FP, and 16% FN. In (D), the MD was 228.92 with 0/15 FL, 0% FN, and 0% FP. In (E), the MD was 221.90 with 2/15 FL and 0% FN 10% FP. In (F), the MD was 223.89 with 2/15 FL, 1% FN, and 20% FP. mark. Her RNFL average measurements were mid-90s in each eye and stable from her first visit. She is currently being evaluated for neurosurgical shunt placement. The prevalence of idiopathic intracranial hypertension without papilledema (IIHWOP) has been reported in approximately 5% of patients with idiopathic intracranial hypertension (IIH) (1). When IIH with papilledema patients were compared with those without papilledema, those without papilledema were more likely to have photopsias, spontaneous venous pulsations, and a slightly lower but elevated opening pressure (1). Of these IIHWOP patients, 70% had normal visual field testing and 20% had what was termed nonphysiologic constriction (1). In those with significant visual field constriction which seems may be nonphysiologic, it is important to consider functional visual loss (2). In a study of functional vision loss and IIH, all patients were diagnosed based on fluctuating visual acuity based on effort or the timing of the examination (2). Although our patient had significant visual field constriction in the setting of no optic nerve swelling, which lends suspicion for a functional component of her vision loss, there was no evidence of functional vision loss despite multiple examinations and testing modalities. Our patient is unique in that there was evidence of visual compromise and presence of clinical manifestations of IIH, but she did not have papilledema or cranial nerve palsy and did not meet all of the radiologic criteria proposed for the diagnosis of IIHWOP described by Friedman et al (3). FIG. 2. Optic nerve photographs showing right and left optic nerves with sharp margins, no edema, and no evidence of a highwater line. e32 Scofield-Kaplan et al: J Neuro-Ophthalmol 2021; 41: e31-e33 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence However, she did have highly elevated lumbar puncture opening pressure and significant egress of fluid during the ONSF, with improvement in the visual acuity and visual fields. There was no change in her RNFL measurements from her presentation to our clinic and follow-up at 6 months, but it is unclear what her baseline was before the onset of her headaches. Although this case is not typical, it outlines that the current published diagnostic criteria for IIHWOP may not include all patients. Until the pathophysiologic mechanism of IIH is completely elicited, we must take into consideration these atypical manifestations when treating this disease process. The presence of optic nerve sheath distension intraoperatively with a normal-appearing nerve on funduscopic examination provides evidence that 1 can develop distension of optic nerve sheath from swelling in the setting of IIH which does not reach the nerve head itself. This is further supported by Salgarello et al (4) where they evaluated the optic nerve transverse diameters and found that 15.8% (3/19) of patients with IIH and abnormal optic nerve diameters had no evidence of optic disc edema. This study mentions he distension of the nerve sheath may precede the development of edema, but the visual fields for these 3 patients are not discussed (4). Furthermore, the presence of retrobulbar nerve swelling and distension can cause visual field loss from both stasis of axoplasmic flow in the axons of retinal ganglion cells and compression-induced ischemia of the retinal ganglion cells (5). It is unclear why this patient’s edema was not transmitted to the nerve head itself, but it is reasonable to consider that in some patients, the swelling may stop before reaching the optic nerve head. Scofield-Kaplan et al: J Neuro-Ophthalmol 2021; 41: e31-e33 Furthermore, it is important to consider the presence of retrobulbar swelling of optic nerve sheath in patients with IIHWOP who present with advanced visual acuity and visual field loss, especially if there is MRI evidence of optic nerve distension. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan; b. Acquisition of data: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan; c. Analysis and interpretation of data: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan. Category 2: a. Drafting the manuscript: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan; b. Revising it for intellectual content: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan. Category 3: a. Final approval of the completed manuscript: S. M. Scofield-Kaplan, K. Patel, F. R. Jones, and R. N. Hogan. REFERENCES 1. Digre KB, Nakamoto BK, Warner JE, Langeberg WJ, Baggaley SK, Katz BJ. A comparison of idiopathic intracranial hypertension with and without papilledema. Headache. 2009;49:185–193. 2. Ney JJ, Volpe NJ, Liu GT, Balcer LJ, Moster ML, Galetta SL. Functional visual loss in idiopathic intracranial hypertension. Ophthalmology. 2009;116:1808–1813 e1. 3. Friedman DI, Liu GT, Digre KB. Revised diagnostic criteria for the pseudotumor cerebri syndrome in adults and children. Neurology. 2013;81:1159–1165. 4. Salgarello T, Tamburrelli C, Falsini B, Giudiceandrea A, Colotto A. Optic nerve diameters and perimetric thresholds in idiopathic intracranial hypertension. J Ophthalmol. 1996;80:509–514. 5. Hayreh SS. Optic disc edema in raised intracranial pressure. V. Pathogenesis. Arch Ophthalmol. 1977;95:1553–1565. e33 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.