Neurological and paraclinical features differentiating Systemic lupus erythematosus, Sjögren's disease, and neuromyelitis optica spectrum disorders.

PURPOSE OF REVIEW: To compare and elucidate the distinguishing clinical, laboratory, and imaging features of neuromyelitis optica spectrum disorder (NMOSD) when it occurs alone and when it coexists with systemic lupus erythematosus (SLE) or Sjögren's disease (SjD).

RECENT FINDINGS: NMOSD is a chronic inflammatory autoimmune astrocitophaty that causes multifocal central nervous system involvement, primarily affecting the optic nerves and spinal cord. Serological testing for AQP4-IgG is the hallmark of NMOSD diagnosis. These antibodies are highly specific for NMOSD and are essential for differentiating it from SLE and SS, which usually test negative for this marker. Around 20-30% of NMOSD patients have associated autoimmune comorbidities, most commonly SLE and SjD, suggesting shared underlying autoimmune mechanisms. In SLE with NMOSD, central nervous system events are more frequent, while SjD often presents with predominant peripheral nervous system involvement.

SUMMARY: Patients with NMOSD and concurrent SLE or SjD have higher morbidity, with increased risk of complications such as paraplegia and seizures, and longer hospital stays compared to those without these comorbidities. NMOSD represents a distinct disease process rather than a neurological complication of SLE or SjD. Identifying distinguishing clinical, laboratory, and imaging features is crucial for accurate diagnosis, guiding treatment strategies, and improving outcomes.