Chiasmitis Secondary to Neuromyelitis Optica 25 Years After Initial Optic Neuritis

Clinical Correspondence Chiasmitis Secondary to Neuromyelitis Optica 25 Years After Initial Optic Neuritis Rui Wang, BA, Ashwini Kini, MD, Bayan Al Othman, MD, Andrew G. Lee, MD N euromyelitis optica (NMO) and NMO spectrum disorder (NMOSD) are inflammatory disorders of the central nervous system characterized by severe, immunemediated demyelination and axonal damage targeting the optic nerve and spinal cord (1). The autoimmune pathogenesis of NMO involves immunoglobulin G (IgG) antibody against aquaporin-4 (AQP4). AQP4 is a waterchannel protein highly concentrated in the spinal cord gray matter, periaqueductal and periventricular regions, and the astrocytic foot processes (2). The hallmark presentation of NMO includes acute attacks of bilateral or rapidly sequential optic neuritis (ON, leading to severe visual loss) or transverse myelitis (TM, causing limb weakness, sensory loss, and bladder dysfunction) with a relapsing course (3). Relapse occurs within the first year after the initial event in 60 percent of patients and within 3 years in 90% (1). Other clinical presentations include brainstem symptoms, encephalopathy, fulminant demyelination, hypothalamic dysfunction, and posterior reversible leukoencephalopathy. In particular, the area postrema syndrome of nausea and vomiting or intractable hiccups occurs with an incidence of 16%–43% in NMOSD (4). We report a 57-year-old woman who presented with a serologically proven NMO exacerbation 25 years after her first unexplained episode of ON. This case documents an unusually long duration between episodes of recurrent ON in a patient with serologically confirmed NMO. Patients with unexplained ON, particularly those with lack of recovery, should be considered for testing for NMO antibody even decades after their initial ON event. Texas A&M College of Medicine (RW, AGL), Bryan, Texas; Department of Ophthalmology (AK, BA), Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas; The Houston Methodist Research Institute (AGL), Houston Methodist Hospital, Houston, Texas; Departments of Ophthalmology, Neurology, and Neurosurgery (AGL), Weill Cornell Medicine, New York, New York; Department of Ophthalmology (AGL), University of Texas Medical Branch, Galveston, Texas; Department of Ophthalmology (AGL), Baylor College of Medicine, Houston, Texas; University of Texas MD Anderson Cancer Center (AGL), Houston, Texas; and Department of Ophthalmology (AGL), The University of Iowa Hospitals and Clinics, Iowa City, Iowa. The authors report no conflicts of interest. Address correspondence to Andrew G. Lee, MD, Blanton Eye Institute, Houston Methodist Hospital, 6560 Fannin Street Suite 450, Houston, TX 77030; E-mail: [e-mail] Wang et al: J Neuro-Ophthalmol 2019; 39: 515-517 A 57-year-old woman presented with acute painless visual loss in her right eye. This was associated with 3–4 episodes of a constant, dull headache localized to the left retrobulbar region. Family history was negative for multiple sclerosis (MS). The medical history was significant for anxiety, depression, and a remote history of recurrent ON in the left eye as her initial demyelinating episode in 1993. After this initial event, the patient experienced several similar episodes of visual loss in the left eye over the next 4 years. She had headache, left eye pain, and visual deterioration that progressively worsened with each episode. Each attack was treated with intravenous corticosteroids with some recovery until the last episode in 1996; this resulted in no light perception (NLP) vision in the left eye. The patient had no further episodes of ON or neurologic symptoms until the time of her current presentation (25 years after the initial episode). During the current episode of ON, serial cranial MRI scans, lumbar puncture, and laboratory testing for infectious and inflammatory etiologies were unrevealing. In retrospect, the patient had several unexplained bouts of nausea and hiccups before admission and was found asleep while sitting in a chair several times by her sister; she had not been diagnosed with narcolepsy. On neuro-ophthalmic examination, the visual acuities were 20/70 in the right eye and NLP in the left eye. Ocular motility was full. There was a left afferent pupillary defect (amaurotic pupil). Ophthalmoscopy demonstrated a normal optic disc on the right and optic atrophy in the left eye. MRI of the brain and orbits demonstrated contrast enhancement of the optic chiasm (Fig. 1). Lumbar puncture showed a normal opening pressure of 18-cm water and normal cerebrospinal fluid (CSF) cell counts, protein, glucose, and oligoclonal bands. CSF myelin basic protein was elevated and consistent with intrathecal production of immunoglobulin against myelin. The IgG albumin index, synthesis rate, and IgG were all elevated, consistent with breakdown of the blood–brain barrier. NMO AQP4-IgG serum antibody test was positive (1:10,000). The patient was started on methylprednisolone 1 g intravenously daily for 3 days before initiating intravenous immunoglobulin (IVIG). She received 4 days of IVIG before discharge. At the last follow-up at 1 month after presentation, the visual acuities had improved to 20/25 in the right eye but remained NLP in the left eye. Optical coherence tomography measurement of the peripapillary retinal nerve fiber 515 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence FIG. 1. Coronal T1-weighted postcontrast MRI with fat suppression (A) and axial T1-weighted postcontrast MRI (B). Enhancement of the optic chiasm is noted (arrows). FIG. 2. Optical coherence tomography scans of the optic nerves at 2 weeks after the patient’s discharge from the hospital. The right optic nerve is normal with a peripapillary retinal nerve fiber layer thickness of 95 mm. The left optic nerve is diffusely pale with thinning of the retinal nerve fiber layer to 38 mm. INF, inferior; NAS, nasal; OD, right eye; OS, left eye; RNFL, retinal nerve fiber layer; SUP, superior; TMP, temporal. 516 Wang et al: J Neuro-Ophthalmol 2019; 39: 515-517 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical Correspondence layer thickness was 95 mm for the right eye and 38 mm for the left eye (Fig. 2). The macular ganglion cell layer demonstrated severe thinning in the left eye but was normal in the right eye. Our patient is unique in that course from the initial episode ON to the present attack that resulted in NLP vision occurred over a 25-year period. Unfortunately, the NMO AQP4-IgG antibody assay was not established until 2004 and did not exist at the time of our patient’s multiple ON episodes in 1993. It is therefore unknown whether the patient’s current seropositivity was present throughout her 25-year course. Interestingly, MRI of the cervical and thoracic spine demonstrated no cord involvement; the patient never had symptoms suggestive of transverse myelitis. Up to 50% of serologically positive patients with NMO, however, develop TM within 5 years of presentation, as many as 80% develop TM within 25 years (2). Patients with suspected NMO should be initially treated with high-dose intravenous methylprednisolone during acute attacks. F or patients with severe symptoms who are unresponsive to corticosteroids, therapeutic plasma exchange is the suggested rescue treatment. Plasma exchange has been demonstrated to be effective including in a randomized, double-masked clinical trial in patients with severe demyelinating disease (5). In contrast to evidence of a positive effect of plasma exchange, the efficacy of IVIG has not been clearly demonstrated in patients with NMOSD. Owing to the recurrent nature of NMO and the potentially poor recovery from attacks, long-term immunosuppression treatment is recommended for the prevention of attacks as soon as the diagnosis of NMO is made. Currently, there is no strict consensus on optimal drug regimen; however, azathioprine, rituximab, and mycophenolate mofetil are all considered first-line monotherapy treatment options. Immunosuppression in patients who are seropositive for AQP4 antibodies is usually continued for at Wang et al: J Neuro-Ophthalmol 2019; 39: 515-517 least 5 years (and often indefinitely) because of the high risk of relapse or conversion to NMO (5). In conclusion, we describe a patient with serologically proven NMO manifesting as chiasmitis 25 years after an initial attack of ON. The current ON episode led to severe visual loss (NLP) in the left eye. This case is unique in having a long duration between the initial ON attack and the current episode of chiasmitis and the left eye visual loss. Clinicians should consider NMO in the differential diagnosis of any patient with acute ON even decades after an initial attack, especially when there is lack of recovery, bilateral involvement, or unusual MRI findings. STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: Rui Wang; b. Acquisition of data: Ashwini Kini; c. Analysis and interpretation of data: Ashwini Kini. Category 2: a. Drafting the manuscript: Rui Wang; b. Revising it for intellectual content: Bayan Al Othman; Category 3: a. Final approval of the completed manuscript: Andrew G. Lee. REFERENCES 1. Wingerchuk DM, Hogancamp WF, O’Brien PC, Weinshenker BG. The clinical course of neuromyelitis optica (Devic’s syndrome). Neurology. 1999;53:1107–1114. 2. Matiello M, Lennon VA, Jacob A, Pittock SJ, Lucchinetti CF, Wingerchuk DM, Weinshenker BG. NMO-IgG predicts the outcome of recurrent optic neuritis. Neurology. 2008;70:2197– 2200. 3. Ghezzi A, Bergamaschi R, Martinelli V, Trojano M, Tola MR, Merelli E, Mancardi L, Gallo P, Filippi M, Zaffaroni M, Comi G. Clinical characteristics, course and prognosis of relapsing Devic’s Neuromyelitis Optica. J Neurol. 2004;251:47–52. 4. Misu T, Fujihara K, Nakashima I, Sato S, Itoyama Y. Intractable hiccup and nausea with periaqueductal lesions in neuromyelitis optica. Neurology. 2005;65:1479–1482. 5. 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