Abstract
Neuromyelitis optica (NMO) and myasthenia gravis (MG) are rare autoimmune disorders. The coexistence of the two disorders, although rare, has been documented. This is a case report of a 16-year-old student who presented with recurrent episodes of transverse myelitis and optic neuritis, 8 years after diagnosis of MG. She presented with visual impairment, relapsing and remitting weakness, numbness and paraesthesia of her lower limbs, with bladder and bowel incontinence. Her examination revealed bilateral optic atrophy, spastic paraparesis of the lower limbs and patchy sensory loss up to thoracic level (T4-5). She had a positive acetylcholine receptor antibody, a positive aquaporin-4 antibody and chest CT finding of thymic enlargement. We therefore confirmed the previous diagnosis of MG and performed a recent diagnosis of background NMO. A high index of suspicion is needed to make a diagnosis of this rare coexistence of NMO and MG in resource-limited settings such as Nigeria.