SNSA

There are multiple definitions:

  1. seronegative spondyloarthropathy(English)

    • member of a group of closely related rheumatic disorders clinically characterized by arthritis and spondylitis, in which serological rheumatoid factor is absent, hence seronegative. They include ankylosing spondylitis, Reiter’s syndrome, psoriatic arthritis, arthritis related to chronic inflammatory bowel disease, and other rarer arthritides
    • AS, IBD
    • Rheumatology
    • https://doi.org…3-662-06294-4_9
  2. sympathetic nervous system activity(English)