Sjogren's syndrome is an autoimmune disorder in which there is immune-mediated damage to the exocrine glands which produce tears and saliva. Many patients (up to 25%) will have extraglandular manifestations of the disease, one of the possibilities of which is renal disease.
A recent article in CJASN by Maripuri et al describes a large case series of patients with primary Sjogren's Syndrome and simultaneous renal disease. In this series, 24 out of 7276 patients seen within the Mayo Clinic system over the past 4+ decades had undergone renal biopsy. What were the most common lesions seen on biopsy?
By far the most consistent result was the presence of interstitial nephritis, which accounted for a full 71% of patients who underwent biopsy. TIN is often association with a distal RTA (and less commonly a proximal RTA) with accompanying hypokalemia and nephrolithiasis. Other lesions included cryoglobulinemia (often with an MPGN pattern on biopsy), FSGS, and other GN's.
Nearly all the patients in this series were treated with corticosteroids; based on the observation that most patients showed a general lack of rapid progression of their kidney disease, the authors justify the use of immunosuppressive therapy in patients with Sjogren's Syndrome.