Background Clinically important renal involvement occasionally occurs in sarcoidosis. Renal manifestations include abnormal calcium metabolism, nephrolithiasis and nephrocalcinosis, and acute interstitial nephritis with or without granuloma formation.

Objectives To analyze the pattern of osteoarticular lesions in patients with sarcoidosis hospitalized in internal medicine departments.

Methods We carried out a systematic retrospective analysis of cases with sarcoidosis admitted in the last 38 years, using hospital databases.

Results 50 patients with sarcoidosis were included in the study (75% women) The mean age at the onset of symptoms of sarcoidosis was 42.47 years [18-70]. The average time between onset of symptoms and diagnosis was 17.74 months with a range of [3-84].Renal involvement was observed in 17 patients (34%) and was revealing in 9 patients (18%). There were 9 women and 8 men with a sex ratio of 0.88. The tubulointerstitial nephropathy was the most common manifestation, found in 12 cases. Glomerular nephropathy and renal lithiasis were present respectively in 2 (4%) and 3 cases (6%). The tubulointerstitial nephropathy found in 12 patients (24%) was biologically characterized by low proteinuria and aseptic pyuria. The kidneys were functionning normally in 3 patients. Renal failure was noted in 9 cases. Advanced renal failure (clearance <10 ml/min) was noted in 3 cases.We have not noted hypertension in our patients. The hypercalcemia was associated with renal failure in 7 cases (77%).

Renal biopsy was performed in 7 cases showing interstitial tuberculoid granuloma in 5 cases and an aspect of chronic interstitial nephropathy with interstitial lymphocytic infiltrate and tubular atrophy in 2 cases. Glomerular nephropathy was present in 2 cases. Microscopic hematuria was present in one case. Renal failure and hypertension were absent. We did not notice any disorder of phosphate and calcium assesments. Biopsy was performed in 2 cases showing a tuberculoid granuloma associated with extra-membranous glomerulonephritis in one case and a remote in the other.

- The kidney stones were found in 3 cases. They were bilateral and unobtrusive in all cases. Recurrent kidney stones were noted in one case. Hypercalciuria and hypercalcemia were found respectively in 3 cases and 2 cases.

Conclusions Several small series have suggested that renal involvement (as defined by either histologic changes in the kidney or a decline in renal function in the absence of a biopsy) occurs in approximately 35 to 50 percent of patients, even if, in most cases, the disease may be silent and undetected for many years or forever.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.5756