Abstract
Primary Sjögren’s syndrome (1° SS) is an autoimmune disorder characterized by dry eyes (keratoconjunctivitis sicca) and dry mouth due to lymphocytic infiltrates of lacrimal and salivary glands. However, SS also affects many extraglandular systems. In SS patients, the pattern of extraglandular manifestations may have a close similarity with the vasculitic features seen in SLE patients that are mediated by immune complexes and complement. However, SS patients also have an increased frequency of lymphocytic infiltration into extraglandular tissues, as might be expected by their increased frequency of lymphoma in comparison to SLE patients. For example, SS patients need to be evaluated for interstitial nephritis (in contrast to the glomerulonephritis of SLE) or interstitial pneumonitis (in comparison to pleurisy of SLE). This chapter will focus on the clinical extraglandular manifestations of primary SS that are not specifically covered in other chapters. These extraglandular manifestations have led to a recently introduced “disease activity” and “organ damage index.” The recognition of these extraglandular manifestations is important since they have prognostic and therapeutic implications. The differential diagnosis of these extraglandular manifestations includes overlapping features with other autoimmune diseases (particularly systemic lupus erythematosus (SLE), scleroderma, dermatomyositis, celiac sprue, and small- and medium-sized vessel vasculitis), infectious diseases that mimic autoimmune disease (particularly hepatitis C, HIV, syphilis, tuberculosis), and predisposition to drug toxicities that may involve extraglandular organs (particularly skin rashes, nephritis, pneumonitis, myositis, and hematopoietic abnormalities).