Introduction:

Anti-Myelin Oligodendrocyte Glycoprotein antibody syndrome is an acquired autoimmune demyelinating disorder presenting as new onset monophasic uni/bilateral Optic neuritis classically involving anterior segments of the optic nerve on MRI. The objective of this case report is to present unusual anatomical involvement of optic nerve in anti-MOG Antibody Syndrome.

Case report:

A previously healthy 8 year old girl presented to our outpatient department with 1 week history of isolated progressive painful diminution of vision in the right eye without any other neurological focal deficits and no history of infective prodrome/vaccination. On examination of right eye the VA was CF 1m (10/200), RAPD positive, fundoscopy showed 360 degree blurring of optic disc margin. MRI brain showed long segment T2 hyperintensity of the entire length of the right optic nerve extending to the chiasma and crossing over to the posterior segment of the left optic nerve. Serum Anti-MOG Ab was positive while AQP4-Antibody was negative. The child was treated with high dose intravenous steroids, which was later switched to oral and tapered. Response to steroids was satisfactory and the patient made a full recovery without any residual vision loss.

Discussion:

A review of literature of Anti-MOG antibody syndrome supports classical MRI findings i.e involvement of the intra-orbital segment of optic nerve, sparing the intracranial segment which suggests the diagnosis of NMOSD. However, the case we present has shown involvement of the entire length of optic nerve and the chiasma with added involvement of optic nerve of opposite side which implies that distinction between Anti MOG-Antibody syndrome and NMOSD cannot be made based on MRI findings making it a diagnostic tool of questionable specificity while warranting a revised clinical criteria of diagnosis for this evolving topic of research.