Renal manifestations of primary Sjogren's syndrome

Background and Objective: Sjogren's syndrome represents a group of diseases characterized by inflammation and destruction of exocrine glands. Renal involvement in Sjogren's syndrome has been reported in 18.4%–67% of patients. Distal renal tubular acidosis (RTA) was reported more common than proximal RTA which can present as acute hypokalemic paralysis. The aim of the present study was to investigate the clinical picture and the outcome in patients with primary Sjogren's syndrome (PSS) with significant renal involvement. Materials and Methods: We conducted a retrospective study of PSS patients with significant renal involvement in our department. Results: A total of 27 patients were included in the study. The mean age was 39.3 ± 4.5 with a mean follow-up of 42 ± 4.8 months. About 18 patients had hypokalemia associated with paralysis, and 4 patients had hypokalemia without paralysis. Female: male ratio was 12.5:1. Number episodes of hypokalemic paralysis range from 1 to 4. The mean time of recovery was 20.4 ± 4 h, and mean potassium requirement was 190 ± 45 mEq intravenously. The mean serum potassium was 2.51 ± 0.55, mean urinary potassium 32 ± 2.3 mEq/day, mean serum bicarbonate 15.03 ± 1.05 mEq/l, and mean blood pH 7.28 ± 0.9. About twenty had distal RTA, and two had proximal RTA. The clinical symptoms were myalgia in 24 (88%), ocular symptoms in 20 (74%), muscular paralysis (66%), oral in 18 (66%), and dental caries in 12 (44%). Five patients underwent renal biopsy of which two showed acute interstitial nephritis, one showed chronic interstitial nephritis, one showed membranoproliferative glomerulonephritis, and one acute tubular injury. Conclusion: The clinical implication of our study is that distal RTA is a common feature of Sjogren's syndrome presenting predominantly as hypokalemic paralysis.