International Journal of Advances in Medicine | February 2023 | Vol 10 | Issue 2 Page 167 International Journal of Advances in Medicine Sriharsha T et al. Int J Adv Med. 2023 Feb;10(2):167-170 http://www.ijmedicine.com pISSN 2349-3925 | eISSN 2349-3933 Case Report An interesting case of seronegative neuro myelitis optica spectrum disorder Tirumalasetty Sriharsha 1 *, Sathish Kumar M. 2 , A. Arun Kumar 1 , Raghav Raj J. 1 , Vikrannth V. 1 , Vinod Raghavan 1 , Kannan Rajendran 1 INTRODUCTION Neuromyelitis optica (NMO) is a chronic inflammatory autoimmune disease of the central nervous system (CNS) characterized by acute optic neuritis (ON) and transverse myelitis (TM). 1 International panel for NMO diagnosis (IPND) was established with the goal of developing improved diagnostic criteria. Core clinical characteristics to diagnose as NMOSD include: optic neuritis, acute myelitis, area postrema syndrome presenting with unexplained hiccups or nausea and vomiting, acute brainstem syndrome, symptomatic narcolepsy or acute diencephalic clinical syndrome, and symptomatic cerebral syndrome with NMOSD typical brain lesions. 2 To diagnose as NMOSD with AQP4-IgG, it should include at least 1 core clinical characteristic and positive test for AQP4 IgG Ab and exclusion of alternate diagnosis. To diagnose as NMOSD without AQP4-IgG and unknown status of AQP4 IgG, and at least 2 core clinical characteristics should be present, out of which one should be either optic neuritis or acute myelitis with longitudinal extension of transverse myelitis (LETM) or area postrema syndrome, dissemination in space (2 or more different core clinical characteristics) and fulfilment of additional MRI requirements and negative for AQP4 IgG Ab. 2 Additional MRI requirements include: acute optic neuritis showing normal brain MRI or optic nerve MRI with T2 hyper intense lesions or T1 enhancing lesions extending over optic nerve length or involving optic chiasma, acute myelitis with intra medullary lesion extending over >3 contiguous segments, area postrema syndrome with lesions in dorsal medulla or area postrema, and acute brainstem syndrome with peri ependymal brain lesions. CASE REPORT A 22-year-old female who presented in April 2022 with history of diffuse headache since 1 week, history of double ABSTRACT Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease that causes severe demyelination, especially in the optic nerve and spinal cord with typical clinical manifestations of acute optic neuritis and transverse myelitis. Seventy to ninety percent of the cases of NMOSD test positive for aquaporin 4 IgG Antibodies (AQP4 IgG Ab). Here we report a case of 22-year-old female who presented with history of diffuse headache since 1 week, history of double vision since1 week and excessive day time sleepiness since2 months. Patient had a past history of bilateral and simultaneous optic neuritis 9 months back. On further evaluation patient was diagnosed as seronegative NMOSD (AQP4 IgG Ab–negative). Keywords: Seronegative neuromyelitis optica, Optic neuritis, Aquaporin-4 IgG antibodies 1 Department of Medicine, 2 Department of Neurology, Saveetha Medical College, Chennai, Tamil Nadu, India Received: 21 December 2022 Revised: 11 January 2023 Accepted: 16 January 2023 *Correspondence: Dr. Tirumalasetty Sriharsha, E-mail: srih97@gmail.com, Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. DOI: https://dx.doi.org/10.18203/2349-3933.ijam20230070