A Case of Neuromyelitis Optica Spectrum Disorder Complicated by Posterior Reversible Encephalopathy Syndrome With Pre-existing Sjögren's Syndrome and Autoimmune Hepatitis.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system (CNS). The coexistence of NMOSD and other autoimmune diseases is well recognized. Additionally, rare cases of NMOSD complicated by posterior reversible encephalopathy syndrome (PRES) have been reported. We present here a case of a young female who developed NMOSD in the clinical course of Sjögren's syndrome (SS) and autoimmune hepatitis (AIH), and who then rapidly developed PRES. A 28-year-old woman was admitted to our hospital with complaints of nausea and singultus, resulting in difficulty eating. She had been experiencing numbness from her neck to her upper arms prior to admission, and she also developed a decrease in visual acuity in her left eye after admission. Brain magnetic resonance imaging (MRI) revealed optic neuritis and a lesion in the area postrema. Based on these imaging findings and those symptoms described as acute myelitis, she was tentatively diagnosed with NMOSD, and treatment with steroids and plasmapheresis was initiated. The following day, however, she developed status epilepticus. Follow-up MRI showed edematous changes in the cortex and deep white matter of the frontal, parietal, and occipital lobes, as well as in the basal ganglia and cerebellum, accompanied by hemorrhage and meningeal enhancement. Her serum test turned out to be positive for anti-aquaporin-4 antibody later. Finally, she was diagnosed with PRES accompanied by NMOSD. It is of note to consider NMOSD when patients with autoimmune diseases present with neurological symptoms such as optic neuritis or acute myelitis. Based on previous reports and temporal changes in her antibody titers, SS may have been involved in the onset of NMOSD in this case. When NMOSD complicates SS, it can be challenging to distinguish CNS lesions caused by SS from those caused by NMOSD. Although previous reports on the coexistence of NMOSD and PRES are limited, several factors have been proposed to explain the mechanism underlying this pathology.