Tubulointerstitial Nephritis Complicated with Primary Sjögren’s Syndrome under Treatment for Type 2 Diabetes Mellitus

Tubulointerstitial nephritis complicated by primary Sjögren’s syndrome in a patient under treatment for type 2 diabetes mellitus was diagnosed in the early stage of the disease by renal biopsy. The symptoms of primary Sjögren’s syndrome, such as thirst and polydipsia, were masked by the characteristic symptoms of type 2 diabetes mellitus. An association between sicca symptoms and diabetes mellitus (types 1 and 2) has been previously reported. Hence, it is possible that there are common underlying immunological mechanisms between primary Sjögren’s syndrome and diabetes mellitus of both types. Intervention with steroids in a timely manner appears to have prevented or slowed the progression of renal impairment.