Aquaporin-4 Antibody Negative Transverse Myelitis in Sj？gren Syndrome

Sj？gren’s syndrome is an autoimmune disease that classically presents with sicca symptoms and arthralgias, yet a small subset of patients develops central nervous system involvement. We report a 64-year-old woman with Sj？gren’s syndrome (ANA positive, anti-SSA 8) who developed abrupt bilateral lower-extremity and abdominal numbness with back pain and urinary retention. Non-contrast thoracic MRI demonstrated a non-enhancing anterior cord lesion from T3 to T6 consistent with transverse myelitis. Cerebrospinal fluid revealed IgG of 10.1 with an IgG/albumin ratio of 0.31, and negative aquaporin-4 (AQP4) IgG. She received IV methylprednisolone 1 g daily for five days, followed by an oral prednisone taper and inpatient rehabilitation. Hydroxychloroquine was trialed intermittently for sicca symptoms but discontinued due to poor tolerance. Neurology initiated mycophenolate mofetil 500 mg twice daily, later titrated to 1g twice daily, as maintenance therapy; after two years, it was held because of recurrent household viral infections. Over nine months without immunosuppression, her neurologic status remained stable, and catheterization frequency decreased from multiple times daily to every few days, leading to sustained discontinuation of mycophenolate. This AQP4-negative presentation highlights diagnostic uncertainty at the Sj？gren’s syndrome-transverse myelitis interface, the importance of antibody testing beyond AQP4 and the need to balance relapse prevention against infection risk through close rheumatology-neurology coordination and symptom-guided re-imaging.