Tubulointerstitial nephritis due to sarcoidosis: Clinical, laboratory, and histological features and outcome in a cohort of 24 patients.

We present a retrospective, single-center study of patients followed for sarcoidosis and presenting with TIN related to this systemic disease. Twenty-four patients were assessed (22 females/2 males). The mean age at diagnosis of TIN was 46.3 years. Extrarenal manifestations were dominated by thoracic involvement (95.8%), peripheral lymph nodes (54.2%), and skin lesions (33.3%). The mean proteinuria level was 0.68 g/24 h. Renal failure was diagnosed in 83.3% of cases with a median estimated glomerular filtration rate at 14.3 mL/min/1.73 m2. Nine patients presented with hypercalcemia and 12 patients with hypercalciuria. Renal biopsy was performed in 58.3% of cases. Six of the 14 patients presented with noncaseating granulomatous interstitial nephritis and eight with interstitial nephritis without granuloma. Granulomatous infiltration of renal parenchyma was complicated by vasculitis in two cases. Corticosteroid therapy was used in all patients. On follow-up analysis, four patients progressed to end-stage renal disease (ESRD) after a mean duration at 45.5 months. In the remaining patients, kidney function statistically significantly improved after one month of treatment compared to the time when the diagnosis was initially established (P = 0.031). We found that the predictive factors of progression to ESRD were multiorgan involvement (P = 0.032), advanced fibrosis F3 (P = 0.0006), and extensive interstitial granulomas (P = 0.007) and these were independently correlated with ESRD...
Source: Saudi Journal of Kidney Diseases and Transplantation - Category: Urology & Nephrology Authors: Tags: Saudi J Kidney Dis Transpl Source Type: research