Background. Primary Sjogren’s syndrome (pSS) is a chronic progressive autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands, which affects the salivary and lacrimal glands, presenting dryness of the mouth and eyes. Renal involvement is easily ignored by the physicians because the clinical symptoms are often insidious. The most common renal disease in pSS is tubulointerstitial nephritis, responsible for renal tubular acidosis in 20%.
Case report. A 36-year-old woman with polyuria and polydipsia for 10 years ago was admitted to the hospital because asymptomatic hypokalemia, kidney stones, and rashes. This woman presented nephrogenic diabetes insipidus and chronic metabolic acidosis for one year, conditions treated with amiloride and sodium bicarbonate. Anti-Sjögren’s antibody A and B were checked and were both found to be positive. At presentation, she had elevated serum osmolality of 301, with a very low urine osmolality of 61, and serum sodium of 143. A metabolic acidosis with hypokalemia and elevated urine pH are consistent with distal renal tubular acidosis (RTA). A kidney biopsy was obtained, which revealed tubular interstitial fibrosis with infiltration of lymphocytes and plasmacytes who extended into intact cortical parenchyma and was consistent with active chronic interstitial nephritis.
Conclusions. Our presenting patient presented renal manifestations of pSS, including diabetes insipidus, renal tubular acidosis type I, tubulointerstitial nephritis, and nephrolithiasis. None of these findings are common presentations of pSS. The presence of all of these symptoms in one individual makes this patient an atypical way to diagnose a primary Sjogren’s syndrome.
