Should Aquaporin-4 Antibody Test Be Performed in all Patients With Isolated Optic Neuritis?

BACKGROUND: Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients. METHODS: We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients. RESULTS: Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up. CONCLUSION: Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.

A case of secondary multiple evanescent white dot syndrome in a patient with preexisting wet age-related macular degeneration.

Purpose: To report a case of secondary Multiple Evanescent White Dot Syndrome in a patient with preexisting wet age-related macular degeneration. Observation: A 75-year-old male on treat and extend regimen for wet age-related macular degeneration (AMD) presented with a sudden loss of vision and saw central dark shadow in the right eye (RE) for a duration of 1 week. There was no significant history preceding the visual loss. Examination showed a visual acuity (VA) of counting fingers at 1 meter in the right eye and 20/25 in the left eye. Anterior segment examination was unremarkable with dilated fundus examination showing a clear vitreous, tortuous blood vessel, a hyperemic disc and fibrosis at the macula. The left eye (LE) examination was unremarkable. Optical Coherence Tomography (OCT) showed fibrosis due to the previous wet AMD and hyperreflective excrescences projecting from the retinal pigment epithelium (RPE) outside of the old area of wet AMD. Fundus Fluorescein Angiogram (FFA) showed hyperfluorescent spots in a wreath-like pattern increasing in intensity in the early phase and showing late staining towards the late phase while Indocyanine green angiography (ICGA) did not clearly delineate the lesions. Fundus autofluorescence (FAF) revealed hyper Autofluorescence (AF) at the posterior pole. Optical Coherence Tomography Angiography (OCTA) revealed a flow reduction in the choriocapillaris of the affected area. Basic blood investigations with Venereal Disease Research Laboratory (VDRL), syphilitic IgM and IgG antibodies, Quantiferon TB gold test, complete renal function tests and liver function tests were performed. All the blood investigations were within normal limits and the workup for syphilis and tuberculosis was negative. The patient was started on 1mg/kg body weight of oral prednisolone (after the non-response to low dose of oral steroids) with the diagnosis of secondary multiple evanescent white dot syndrome (MEWDS) secondary to wet AMD. The patient was followed up every weekly and the last visit showed improvement in visual acuity to 20/50 with resolution of lesions on FAF and OCT macula. Conclusion and importance: Secondary MEWDS is extremely rare and unique in terms of its presentation and its association with preexisting chorioretinal disease where there is damage to the choriocapillaris- Bruch's membrane-RPE complex. This case report highlights one such rare case scenario and how multimodal imaging helps in the diagnosis, management and follow-up of patients with secondary MEWDS.