Abstract |
To evaluate the validity of the prevailing concept that Susac syndrome (SS), a rare microvasculopathy of the brain, retina, and inner ear, is a self-limiting disease. We performed a literature search to identify all cases of SS reported between 1973 and October 2015. If available, we determined their demographics, duration of follow-up, and the clinical course that was labeled as monocyclic or polycyclic. We attempted to determine the number of relapses and the relapse rate in patients with polycyclic disease. Our literature search yielded 185 relevant publications reporting 405 cases of SS. The duration of follow-up could be determined in 247/405 cases, with a range 0.5-312 months. The mean was 41 months but the distribution was skewed, with a median of 24 months. Defining the clinical course as monocyclic or polycyclic was possible in 102 patients who were followed for greater than 24 months; 53 were identified as having a polycyclic course. Patients labeled polycyclic were followed longer than those labeled monocyclic (median 62 vs 42 months, P < 0.001). The number or frequency of attacks per patient could not be determined. The follow-up of published cases of SS is short, creating an inherent bias toward the impression that the disease is self-limiting. Our findings suggest that stratification of SS into monocyclic, polycyclic, and chronic continuous courses may oversimplify the phenotype of SS; instead, the possibility of a relapsing-remitting course must be considered in all patients with this disorder. |
OCR Text |
Show Letters to the Editor The 14th Hoyt Lecture: Ischemic Optic Neuropathy: The Evolving Profile, 1966-2015: Response D r. Parsa raises important issues in his letter to the editor regarding the 14th Hoyt Lecture. He rightfully wishes to credit Hoyt for emphasizing the baseline optic disc structure in nonarteritic anterior ischemic optic neuropathy (NAION). However, he disputes the fact that Hayreh (1) documented this occurrence in his 1974 study of cupping in anterior ischemic optic neuropathy (AION) stating that the article focused on cupping after arteritic AION. He further suggests that other authors and I may have performed "only a perusal of manuscript titles and author listings, without recollection of the manuscript contents themselves. . ."when citing Hayreh's paper. However, Hayreh's publication, although focused on arteritic AION, included data on fellow eye cupping in NAION; of 12 unilateral cases of NAION, 9 fellow eye optic discs had no physiologic cup and 2 had a small cup-disc ratio of 0.2. I would refer Dr. Parsa back to Tables I and II of that article and references to that same data in subsequent reports by Beck and others (2,3). Although this in no sense diminishes Hoyt's seminal focus on the finding in 1982, the information was certainly in the literature as I stated. Knowing Dr. Hoyt and that no significant manuscript in the field escaped his gaze, I suspect that he had read it. Dr. Parsa goes on to summarize his recently proposed theory that abrupt vitreous separation from the optic disc, with direct axonal injury because of "shear and stress forces" is responsible for the syndrome of NAION, rather than ischemia, which most investigators in the field believe is the major component. This proposal, published as an editorial (4), was thought provoking but did not constitute peer-reviewed scientific evidence and, therefore, was not included in my review of the evidence-based evolution of our understanding of NAION (5). The theory does not take into account an extensive literature including fluorescein angiographic evidence of impaired optic disc perfusion in NAION (6,7) and histopathologic documentation of infarcts in NAION (8-11). Furthermore, although there is a large literature around vitreopapillary traction, studies generally describe an entirely different syndrome of disc edema and hemorrhage without the diminished optic nerve function seen in patients with NAION (12,13). That said, we clearly have much to learn about the specific Clomiphene Citrate Associated With Palinopsia W e were interested to read the article by Yun et al (1) describing palinopsia with the use of topiramate. We evaluated a patient with persistent palinopsia after the use of clomiphene citrate. 220 pathophysiology of this disorder, and it is possible that vitreopapillary mechanics may somehow be involved. I believe the neuro-ophthalmology community would welcome the evidence. Anthony C. Arnold, MD UCLA Department of Ophthalmology, Stein Eye Institute, Los Angeles, California The author reports no conflict of interest. REFERENCES 1. Hayreh SS. Pathogenesis of cupping of the optic disc. Br J Ophthalmol. 1974;58:863-876. 2. Beck RW, Savino PJ, Repka MX, Schatz NJ, Sergott RC. Optic disc structure in anterior ischemic optic neuropathy. Ophthalmology. 1984;91:1334-1337. 3. Beck RW, Servais GE, Hayreh SS. Anterior ischemic optic neuropathy. IX. Cup-to-disc ratio and its role in pathogenesis. Ophthalmology. 1987;94:1503-1508. 4. Parsa CF, Hoyt WF. Nonarteritic anterior ischemic optic neuropathy (NAION): a misnomer. Rearranging the pieces of a puzzle to reveal a nonischemic papillopathy caused by vitreous separation. Ophthalmology. 2015;122:439- 442. 5. Arnold AC. Ischemic optic neuropathy: the evolving profile, 1966-2015. The 14th Hoyt lecture. J Neuroophthalmol. 2016;36:208-215. 6. Arnold AC, Hepler RS. Fluorescein angiography in acute nonarteritic anterior ischemic optic neuropathy. Am J Ophthalmol. 1994;117:222-230. 7. Arnold AC, Costa RM, Dumitrascu OM. The spectrum of optic disc ischemia in patients younger than 50 years. Trans Am Ophthalmol Soc. 2013;111:93-118. 8. Quigley HA, Miller NR, Green WR. The pattern of optic nerve fiber loss in anterior ischemic optic neuropathy. Am J Ophthalmol. 1985;100:769-776. 9. Levin LA, Louhab A. Apoptosis of retinal ganglion cells in anterior ischemic optic neuropathy. Arch Ophthalmol. 1996;114:488-491. 10. Tesser RA, Niendorf ER, Levin LA. The morphology of an infarct in nonarteritic anterior ischemic optic neuropathy. Ophthalmology. 2003;110:2031-2035. 11. Knox DL, Kerrison JB, Green WR. Histopathologic studies of ischemic optic neuropathy. Trans Am Ophthalmol Soc. 2000;98:203-222. 12. Katz B, Hoyt WF. Intrapapillary and peripapillary hemorrhage in young patients with incomplete posterior vitreous detachment. Signs of vitreopapillary traction. Ophthalmology. 1995;102:349-354. 13. Wisotsky BJ, Magat-Gordon CB, Puklin JE. Vitreopapillary traction as a cause of elevated optic nerve head. Am J Ophthalmol. 1998;126:137-139. A 22-year-old man reported that whenever he saw a moving object, some blurred images trailed the real object "like shadows." He also stated that "When I watched the screen of a smart phone, I could see a dim afterimage of the screen after the phone was removed." These symptoms became more bothersome especially in darkness or in dim light. He had suffered from parotitis and orchitis four months previously, and had Letters to the Editor: J Neuro-Ophthalmol 2017; 37: 216-221 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. |