Sjögren Syndrome



Sjögren Syndrome


Stephen M. Bonsib, MD










Renal biopsy in Sjögren syndrome typically shows a patchy but heavy interstitial infiltrate. The glomeruli are usually normal. The infiltrate forms broad sheets of cells that separate the tubules.






This biopsy in Sjögren syndrome shows the plasma cell-rich image nature of the infiltrate. The interstitium is greatly expanded and tubular atrophy and interstitial fibrosis has developed.


TERMINOLOGY


Abbreviations



  • Sjögren syndrome (SS)


Synonyms



  • Sicca syndrome


Definitions



  • Autoimmune disorder involving exocrine glands, particularly salivary and lacrimal glands



    • May be primary or a component of other autoimmune disorders



      • Rheumatoid arthritis in 50%


      • Systemic sclerosis in 5%


      • Systemic lupus erythematosus in 5%


ETIOLOGY/PATHOGENESIS


Etiology Not Clear



  • May be multifactorial


  • Initiation by an exogenous factor, possibly viral



    • Epstein-Barr virus implicated


    • Genetic predisposition


  • Lymphoplasmacytic inflammation with atrophy of eccrine, salivary, and lacrimal glands



    • T-lymphocyte response


    • B-lymphocyte hyper-reactivity



      • Autoantibodies: Rheumatoid factor (RF), SS-A (Ro) and SS-B (La)


    • Injury to salivary gland epithelium


CLINICAL ISSUES


Epidemiology



  • Age



    • 45-55 years


  • Gender



    • Female predominance (F: M = 9:1)


Presentation



  • Renal disease ˜ 5%



    • Tubulointerstitial disease



      • Distal renal tubular acidosis 70-80%


      • Renal failure 25-30%


      • Tubular proteinuria 20%


      • Hypercalcuria, occasionally hypokalemia


      • Fanconi syndrome (rare)


    • Glomerulonephritis 5-15%



      • Proteinuria &/or hematuria &/or renal failure


  • Keratoconjunctivitis (dry eyes) > 95%


  • Xerostomia (dry mouth) > 95%


  • Cutaneous vasculitis 10-30%



    • Associated with cryoglobulins in 30%


    • Small to medium-sized vessels


  • Peripheral neuropathy ˜ 10%


  • Interstitial lung disease ˜ 10%


  • Lymphoma 40x increased risk



    • B-cell lymphoma or Waldenström macroglobulinemia


Laboratory Tests



  • 50-90% have SS-A antibodies



    • ANA, anti-SS-B, and RF often positive


  • Hypergammaglobulinemia


  • Organ-specific antibodies



    • Thyroid microsome


    • Thyroglobulin


    • Salivary duct epithelium


    • Gastric parietal cells


  • Low C4, C3 (9%)


Treatment



  • Immunosuppression: Corticosteroids, Rituximab

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Sjögren Syndrome
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