Multiple autoimmune disorders in a patient with neuromyelitis optica spectrum disorder presenting with rhabdomyolysis

Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disease of the central nervous system characterised by longitudinal extensive transverse myelitis and involvement of the optic nerve and is associated with many autoimmune disorders. The index case, a known case of Hashimoto's thyroiditis, presented with quadriparesis and tea-coloured urine. Investigations revealed ongoing rhabdomyolysis related to autoimmune myositis and autoimmune haemolytic anaemia leading to pigment-induced acute kidney injury. Suspicion of other autoimmune disease prompted an immunological workup, which showed a positive Schirmer's test and a positive anti-nuclear antibody (ANA) antibody test, disclosing Sjögren's syndrome. Lack of improvement in muscle power with corticosteroids despite reduction in muscle enzymes led to an MRI of the spine, which showed longitudinal extensive transverse myelitis and involvement of the intracranial segment of the right optic nerve. These findings, along with a positive test for aquaporin-4 antibodies, confirmed NMOSD. Treatment with cyclophosphamide led to improvement in muscle power to grade 4 at discharge.