Kidney Week

Abstract: PUB028

Renal Sarcoidosis Presenting as an Isolated Manifestation: A Rare Clinical Entity

Session Information

• Publication Only

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Zghayer, Aseel, Loyola University Chicago Stritch School of Medicine, Chicago, Illinois, United States

Aseel Zghayer, MD

• Picken, Maria M., Loyola University Chicago Stritch School of Medicine, Chicago, Illinois, United States

Maria M. Picken, MD, PhD, FASN

• Leehey, David J., Loyola University Chicago Stritch School of Medicine, Chicago, Illinois, United States

David J. Leehey, MD

Introduction

Sarcoidosis is a multisystem disorder with accumulation of non-necrotizing granulomas in the lungs and other organs. Renal involvement in sarcoidosis is rare, and its exact incidence remains uncertain. When present, it may manifest as interstitial nephritis, with or without granulomas, nephrocalcinosis, or hypercalciuria. Here, we describe a rare presentation of sarcoidosis with renal involvement as the only manifestation.

Case Description

A 65-year-old man with a history of chronic lymphocytic leukemia (CLL) in remission presented with lethargy, weight loss and anorexia. He was found to have acute kidney injury (AKI) on chronic kidney disease (CKD) of unclear etiology and hypercalcemia (total calcium 14.2 mg/dL). Urinalysis revealed +1 protein without hematuria or pyuria. 24-h urine protein was 1.2 g. Further workup showed low parathyroid hormone (PTH), normal PTH-related peptide (PTHrP), low 25-hydoxy vitamin D₃ (7 ng/mL) and normal 1,25-dihydroxy vitamin D₃ (43 pg/mL), and high angiotensin-converting enzyme (ACE) levels. Bone marrow biopsy showed no evidence of plasma cell neoplasm or a lymphoproliferative disorder and CT chest abdomen pelvis showed no acute abnormality. Kidney biopsy revealed interstitial nephritis with noncaseating granulomas consistent with sarcoidosis (Figure 1). He was treated with prednisone with improvement of hypercalcemia and renal function.

Discussion

The diagnosis of renal sarcoidosis is challenging in the absence of involvement of other organs with sarcoidosis. In our case, the normal level of 1,25-dihydroxy vitamin D₃ (1,25(OH)₂D₃) despite low 25-hydroxy vitamin D₃ (25(OH)D₃) levels with an elevated 1,25(OH)₂D₃/25(OH)D₃ ratio suggested calcitriol production due to granulomatous processes (Rohmer et al., Ocul Immunol Inflamm 2020;28:341-7). In such instances, renal sarcoidosis should be considered in the differential diagnosis, particularly when encountering cases of acute or chronic renal failure with uncertain causes. Early identification and treatment can facilitate renal function recovery and reduce the risk of interstitial fibrosis.

Figure 1.