Sjögren syndrome beyond dry eye: Optic neuritis, an extraglandular manifestation or an expression of polyautoimmunity?

The presence of extraglandular manifestations of Sjögren's syndrome opens a wide debate in the field of neurology, where the association or similarity with multiple sclerosis and optical neuromyelitis spectrum raises the need for better markers, among which anti-aquaporin 4 antibodies have gained more relevance. Likewise, the technique for measuring these autoantibodies, carried out in serum and in cerebrospinal fluid, is useful for diagnosis and prognosis. The following is a case of Sjögren's syndrome without sicca symptoms, with unilateral optic neuritis.