Abstract: SA-PO0543
A Challenging Case of Renal Sarcoidosis Presenting with Hypercalcemia and Normal 1,25-Dihydroxyvitamin D Levels: Diagnostic and Therapeutic Considerations
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Clinical - 3
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Authors
- Sharma, Harsh, Kasturba Medical College Manipal, Manipal, KA, India
- Allam, Krishna C, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States
- Karam, Sabine, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States
Introduction
Renal sarcoidosis is a rare manifestation of systemic sarcoidosis and presents with kidney dysfunction secondary to hypercalcemia, interstitial nephritis with or without granuloma formation and nephrocalcinosis. Elevated 1,25 dihydroxy vitamin D (1,25 OH vit D) levels are usually supportive of the diagnosis due to increased production of (1,25 OH vit D) by activated mononuclear cells in granulomas.
Case Description
A 53-year-old male with a past medical history significant for obesity, mild intermittent asthma, poorly controlled hypertension, and type 2 diabetes presented for evaluation of worsening kidney function. His creatinine (Cr) level was 2.73 mg/dL as compared to 1.96 mg/dL a year prior. His serum calcium (Ca) was elevated at 11.2 mg/dL. Hypercalcemia workup revealed a parathyroid hormone (PTH) level at 14 pmol/mL (15-65) , a non-significantly elevated PTH-related protein level at 4.4 pmol/L (0-2.3), a normal 1,25 OH vit D level at 49.6 pg/mL (19.9 - 79.3) and a low 25 hydroxy-vitamin D (25-OH vit D) at 19 ng/mL (20-50). A workup for plasma cell disorders including a serum protein electrophoresis with immunofixation and a serum free light chain assay was negative. His CRP level was elevated at 37 mg/L (< 5 mg/l). A PET scan showed bilateral hilar, mediastinal and abdominal lymphadenopathy. Endobronchial ultrasound-guided biopsy of a lymph node revealed non-caseating granulomas. He refused a kidney biopsy and was initiated on 40 mg of prednisone daily for empiric treatment of renal sarcoidosis. His Ca and CRP levels normalized, and his Cr level improved to 1.98 mg/dL. He was thereafter switched to mycophenolate mofetil 1 g twice daily with stabilization of his kidney function and Ca levels.
Discussion
Despite normal 1,25 OH vit D levels, our patient had tissue biopsy proven sarcoidosis with hypercalcemia. Postulated mechanisms include increased bone resorption driven by pro-inflammatory cytokines such as tumor necrosis factor- α, tissue expression of PTHrp with circulating serum level hardly ever exceeding normal limits and intestinal hyper-responsiveness to 1,25 OH vit D. In addition, decreased renal calcium excretion due to nephrocalcinosis can entertain the hypercalcemia. A normal 1,25 OH vit D level should not exclude this diagnosis.