A Unique Case of Primary Renal Sarcoidosis

Introduction: Renal sarcoidosis is usually associated with other extra-renal sarcoidosis, it usually involves the lungs and renal involvement is only 0.7%. Initial lab work shows elevated serum creatinine, a bland urine sediment or sterile pyuria and high or high-normal calcium. Kidney biopsy is not diagnostic but is useful in making the diagnosis and ususally shows noncaseating granulomas in the interstitium. Treatment of choice is glucocorticoids and is started at 1mg/kg/day with maximum of 80 mg/day followed by a slow taper. Glucocorticoid doses required for renal sarcoidosis are higher than extra-renal sarcoidosis. Case Description: 44-year-old male patient with past medical history significant for kidney stone, hypertension presents with complaints of high blood pressure and worsening kidney functions, on further investigation it was found that he had a left-sided renal biopsy in Miami about 4 years ago which showed nephrosclerosis with 50% sclerotic glommeruli, focal moderate interstitial fibrosis and mild arteriolosclerosis, chronic inflammatory infiltration with focal tissue calcinosis. At the time of initial diagnosis, his lab work revealed elevatded creatinine, calcium levels with proteinuria. No pulmonary lesions were found. He was started on 50 mg of prednisone daily and gradually taper down to 10 mg every other day and he has been on this dose for about 1.5 year now. He has not had any kidney stones since he started treatment for sarcoidosis and currently he requires supplements for low vitamin D levels. Discussion: Though primary renal sarcoidosis is uncommon it is important to keep it as a differential in a person with no other extrarenal manifestation of sarcoidosis who presents with elevated creatinine and calcium levels. Patients with renal sarcoidosis are well managed with corticosteroids, though most patients require a higher dose of corticosteroids but some of them can be well managed on lower doses like our patient who was started only on 50 mg of prednisone and was gradually tapered down to 10 mg every other day. He continues to have CKD stage 3B even on this lower doses of corticosteroids and he has been stable there for the last few years. Also another noticeable point is that the patient has low vitamin D stores and requires supplementation currently after being treated for sarcoidosis for a 4 years.