Abstract
INTRODUCTION: Longitudinally extensive transverse myelitis (LETM) in children raises concerns for serious underlying autoimmune conditions. Neuromyelitis optica spectrum disorder (NMOSD), often associated with anti-aquaporin-4 (AQP4) antibodies, can present with LETM and is increasingly recognised in paediatric populations. Juvenile systemic lupus erythematosus (jSLE) may manifest with central nervous system involvement, including myelitis. While NMOSD and SLE can occur independently, their coexistence—especially at initial presentation—is rare and diagnostically challenging. We report a paediatric case of LETM that led to the simultaneous diagnosis of NMOSD and jSLE, highlighting the importance of early recognition, comprehensive autoimmune evaluation and multidisciplinary collaboration. CASE DESCRIPTION: An 8-year-old girl presented on Christmas evening with sudden bilateral leg numbness, difficulty standing, back pain, and urinary retention. Her history was otherwise unremarkable, aside from an innocuous fall 10 days earlier. Prior to admission, she developed thoracic and lumbar back pain and constipation over four days. Examination revealed lower limb weakness (power 4/5), brisk reflexes, abdominal tenderness, and a sensory level at T9/T10, but no rash, fever or optic neuritis on ophthalmic evaluation. She had thromboyctopaenia (platelet count nadir of 42) and lymphopenia. MRI scan of the spine showed long-segment spinal cord dilation suggestive of transverse myelitis. She was treated with 5 days of IV methylprednisolone, which led to partial and comparatively quick improvements in her mobility. She was discharged on a tapering course of prednisolone commencing at 40 mg with a plan to wean over the course of 5 weeks and twice daily intermittent catheterization. Three weeks later, she was readmitted with fever and signs suggestive of meningoencephalitis; her inflammatory markers were elevated, and she responded to antibiotics and antiviral therapy with all cultures (urine, blood, CSF) and CSF PCRs negative. Serum and CSF aquaporin-4 antibody positivity supported a diagnosis of NMOSD, while her ANA and dsDNA positivity indicated systemic lupus erythematosus (SLE). There was no evidence of other systemic involvement, and repeat MRI showed near complete resolution of inflammation. There were no significant neurological sequelae aside from ongoing twice daily CIC, gait was normal though running was still impaired. This child met criteria for SLE and NMOSD which can co-exist with lupus. DISCUSSION: This case underscores the importance of recognizing autoimmune overlaps in children presenting with transverse myelitis, particularly when associated with positive autoantibodies. Autoantibodies associated with SLE and Sjogrens have been associated with CNS AQP4 antibodies. In these patients NMOSD can precede or follow their rheumatological diagnosis. The coexistence of SLE and NMOSD influences management and prognosis, requiring a multidisciplinary approach to optimize outcomes and prevent future relapses or neurological sequelae. There was input from tertiary and quaternary neurology teams as well as rheumatology, neurology, urology and radiology teams. Discussions considered whether all features present at diagnosis could be explained by just one or the other diagnosis. It was felt that both were co-existing, and the NMOSD was distinct from neuropsychiatric SLE with the presence of LETM driven by AQP4 antibodies. She met SLICC and 2019 ACR criteria for SLE though mainly immunological and haematological domains (strongly positive ANA and dsDNA, thrombocytopaenia, leucopaenia and positive DCT). Given the associated risk of recurrent CNS inflammation with AQP4 antibodies present the aim was to prevent further flares and following discussions with a specialist neurologist in neuroinflammation alongside local rheumatology and neurology she was commenced on MMF as maintenance therapy. A longer weaning course of prednisolone was also prescribed. She still undergoes regular reviews and remains a positive and stoic character. Her physical function has recovered however her bladder residual volume is still significant to require CIC. She has recently had an admission for a urinary tract infection as a complication of this. KEY LEARNING POINTS: • Consider autoimmune rheumatological diseases in cases of NMOSD and vice versa - the overlap is documented and has consequences for prognosis and treatment. • Management of these complex cases is multi-disciplinary, treatment should be guided by all specialties involved and specialist advice sought as needed. • NMOSD associated with autoimmune disease is considered more severe with more frequent relapses and worse prognosis, our case highlights an example of early intervention where prompt treatment with IV steroids and early initiation of DMARD have so far provided rapid initial recovery and a period of relative stability. • Trasnverse myelitis can be one of the neurological presentations of jSLE, which can be clinically, radiologically and immunologically differentiated from coexisting NMOSD, which has implications on planning the treatment too. • Although reported in adults, coexistence of jSLE and NMOSD is exceedingly rare, limited to a handful of case reports.