Renal Involvement in Sarcoidosis

Abstract

Introduction: Sarcoidosis is a granulomatous systemic disease. Renal damage is rare but it can evolve to chronic renal failure (CRF). The aim of our work is to describe the clinical, paraclinical, histological and evolutionary profile of renal involvement during sarcoidosis and to identify the progression factors leading to CRF. Materials and Methods: This is a retrospective descriptive study from January 2009 to December 2022. We collected the medical records of patients with sarcoidosis and renal involvement. To study the progression factors leading to CRF we identified two groups of patients: the group with normal renal function and the group that developed CRF. Results: We included in our study 17 patients with renal sarcoidosis. Their mean age was 45 ± 14.7 years and the sex ratio was 0.4. Renal involvement is revealing of sarcoidosis in 76% of cases. Renal failure was diagnosed in 88% of patients. Proteinuria was positive in 76.5% of cases, leukocyturia in 59% of patients and hematuria in 41% of patients. Renal biopsy was performed in 15 patients showing tubulointerstitial nephropathy in all biopsies. Epithelioid and gigan-to-cellular granuloma without caseous necrosis was found in 46% of cases. Associated glomerular involvement such as segmental and focal hyalinosis was found in 2 patients. Corticosteroid therapy was initiated in 88% of patients for a median duration of 15 months. Normalization of renal function was achieved in 41% of patients, while 59%, i.e. 10 patients, retained a CRF, including 2 who were on dialysis. We showed a statistically significant relationship between the evolution towards CRF and the presence of interstitial fibrosis > 25%. Conclusion: Despite its rarity, renal involvement can be revealing of sarcoidosis, which can condition the prognosis and lead to CRF. Its detection allows an early diagnosis and treatment.