Seropositive Neuromyelitis Optica in a Case of Undiagnosed Ankylosing Spondylitis: A Neuro-Rheumatological Conundrum

Abstract

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy against foot processes of aquaporin-4 (AQP4) water channels. Patients with NMOSD tend to have other coexisting autoimmune/connective tissue diseases. However, AQP-4-antibody-positive NMOSD coexisting with ankylosing spondylitis (AS) is rare. AS is an immune-mediated disorder, a subset of axial spondyloarthropathies, which commonly manifests as chronic inflammatory back pain in young people, and it has a strong association with HLA-B27. In this study, a 35-year-old Indian man with an undiagnosed progressive axial spondyloarthropathy (i.e., AS) is reported presenting with acute-onset longitudinally extensive transverse myelitis, a clinical subset of NMOSD. Neuromyelitis optica spectrum disorder (NMOSD), a primary demyelinating disorder of the central nervous system (CNS), is an autoimmune astrocytopathy against foot processes of aquaporin-4 (AQP4) water channels, which manifests with optic neuritis, longitudinally extensive transverse myelitis (LETM), area-postrema syndrome, brainstem syndrome diencephalic syndrome, and cerebral syndrome. 1 – 4 Ankylosing spondylitis (AS) is an immune-mediated disorder, a subset of axial spondyloarthropathies, which commonly manifests as chronic inflammatory back pain in young people, and it has a strong association with HLA-B27. 5 , 6 AS characteristically targets the axial skeleton, peripheral joints, entheses (connective tissues between tendons/ligaments and bones), and gut. 5 , 6 Patients with NMOSD tend to have other coexisting autoimmune/connective tissue diseases. 7 For example, cases with NMOSD and multiple sclerosis, which are other autoimmune primary demyelinating disorders of the CNS, have been reported. 8 , 9 However, concurrent existence of AS and NMOSD in the same patient even over years of disease course is rare. 10 , 11 In addition, studies describing neurological manifestations of AS are limited, 12 and they focus on joint inflammation and long-standing bony pathology (ankylosis) related to compressive myelopathy, myelo-radiculopathy, and cauda equina syndromes. 12 , 13 The authors present a case of a young Indian man with an undiagnosed progressive AS (misdiagnosed and mismanaged by an indigenous medical practitioner) presenting with acute-onset LETM variant of AQP4-positive NMOSD. A 35-year-old healthy, non-comorbid man from rural India came to the outpatient department with complaints of persistent tingling, numbness, and weakness of both lower limbs (right more than left) for 10 days. The clinical picture showed acute-onset urinary retention, which was relieved by urinary cathete...

Neuromyelitis optica spectrum disorder in a patient with ankylosing spondylitis: A case report

“…Patient with NMOSD tends to have other coexisting autoimmune/connective tissue diseases. However, AQP‐4‐antibody‐positive NMOSD coexisting with ankylosing spondylitis (AS) is rare 11 . AS and NMOSD share an obscure pathogenesis, while a T‐cell‐based autoimmunity is a possible explanation for the disease process considering the recently role of T cell in NMOSD and molecular mimicry might be an environmental factor that results in co‐pathogenesis 12 .…”

“…11 AS and NMOSD share an obscure pathogenesis, while a T-cell-based autoimmunity is a possible explanation for the disease process considering the recently role of T cell in NMOSD and molecular mimicry might be an environmental factor that results in co-pathogenesis. 12 Ritwik Ghosh et al 11 reported a 35-year-old Indian man with an undiagnosed progressive axial spondyloarthropathy (i.e., AS) is reported presenting with acute-onset LETM, a clinical subset of NMOSD. Lin et al describe the case of a 46-year-old Chinese female with bilateral lower limbs and perineum numbness.…”