D3.397 - MOG Antibody–Associated Bilateral Optic Neuritis in a Child Following Mycoplasma Infection

MOG antibody-associated disease (MOGAD) is an autoimmune disorder that typically presents with optic neuritis, often associated with visual loss and color vision impairment, particularly in children. This case highlights the diagnostic challenges of a 6-year-old girl with acute bilateral visual loss, who was later diagnosed with MOG-positive bilateral optic neuritis following a Mycoplasma infection. 

A 6-year-old girl presented to our hospital with acute bilateral visual loss and reduced colour vision, first noticed at school. She was referred by her GP, assessed by an optician, and urgently referred to ophthalmology, where bilateral papilledema was confirmed. The patient was then seen by the paediatric team, and a CT head was performed, which was normal. She was subsequently transferred to a tertiary neurology centre for further investigation. 

At the tertiary centre, an MRI confirmed bilateral optic neuritis, and serum testing revealed MOG antibody positivity. A lumbar puncture was performed and was normal. Her autoimmune workup, thyroid function, and other baseline investigations were within normal limits. She was diagnosed with MOG-positive bilateral optic neuritis based on MRI and antibody results. 

The patient received intravenous methylprednisolone followed by a tapering course of oral steroids, resulting in significant improvement in visual acuity. Follow-up ophthalmology assessments confirmed good visual recovery, with her right visual acuity improving to approximately 60% of baseline, while the left side showed greater recovery. There were no limitations to her daily activities, and she was able to return to school. 

MOGAD is a rare but increasingly recognized cause of bilateral optic neuritis in children, particularly following infections like Mycoplasma pneumoniae. The diagnosis is often challenging, as it requires a high degree of suspicion and the detection of MOG antibodies in the serum. This case is particularly noteworthy as it presents a child with acute visual disturbances and an autoimmune response following an infection, with good recovery after corticosteroid therapy. 

The role of infections as potential triggers for MOGAD highlights the need for thorough evaluation in cases of optic neuritis with a possible history of infectious symptoms. The patient’s presentation and subsequent management underscore the importance of early diagnosis and prompt treatment to prevent permanent visual impairment. 

MOG-positive bilateral optic neuritis should be considered in children with acute bilateral visual loss, particularly following infection. Early multidisciplinary assessment with immunological testing is essential. Prompt corticosteroid treatment can result in good visual recovery.