SAT-751 Hypocalcemia And Hypoparathyroidism In A Patient With Sarcoidosis: A Case Report

Abstract Disclosure: S. Thambuluru: None. Background: Sarcoidosis is a multisystem disease characterized by non-caseating granulomas, with mostly frequent involvement in the lungs (1). Hypercalcemia is a well recognized phenomena in patients with sarcoidosis due to unregulated synthesis of 1 ,25-dihydroxyvitamin D3 by macrophages within the granulomas (2). Here we present a lesser known phenomena of hypocalcemia with hypoparathyroidism in a patient with sarcoidosis. Clinical Case: 55yr old african american male with pulmonary sarcoidosis presented to endocrine clinic for evaluation of hypocalcemia. Pt denied history of neck surgery, radiation, autoimmune diseases, symptoms of adrenal insufficiency, yeast infections or thyroid dysfunction. No history of developmental issues. Not on any supplements. Patients reported symptoms of muscle cramps since starting steroids for treatment of sarcoidosis 3 weeks prior. Physical exam had positive chvostek sign. Initial testing noted calcium level of 6.5 mg/dl (8.6-10.3 mg/dl) with low PTH of 10 pg/ml (16-77 pg/ml), elevated phosphorus of 4.8 mg/dl (2.5-4.5 mg/dl), mildly low vitamin D25OH 29 ng/ml (30-100), 1,25 vitamin D 41 pg/ml (18-72). Labs consistent with hypocalcemia from hypoparathyroidism. Work up for etiology of hypoparathyroidism with PTH antibody, TPO ab, CASR mutation, 21 hydroxylase antibody testing was all negative. Calcium 600 mg twice a day, calcitriol 0.25mcg daily, vitamin D3 2000 IU daily were started with improvement in calcium levels and symptoms. Possible diagnosis: idiopathic hypoparathyroidism vs hypoparathyroidism secondary to sarcoidosis infiltration of parathyroid glands. Discussion: Typically we associate hypercalcemia with sarcoidosis, but this case is rare in that there is a coexistence of sarcoidosis and hypocalcemia. This patient's calcium levels was >7.5 mg/dl prior to starting prednisone. A few weeks after starting treatment patient calcium dropped further to 6.5 mg/dl with development of hypocalcemic symptoms. Possible explanation could be the steroids inhibited the granulomatous production of 1,25-dihydroxy vitamin D and therefore unmasking underlying hypoparathyroidism (1). Case brings to light a rare association of hypocalcemia and sarcoidosis, and to be aware of possible shifts in calcium regulation with treatment of sarcoidosis. References: 1.Dodos, K., Kalamara, V. T., Georgakopoulou, V. E., & Kavoura, P. (2024). Primary Ηypoparathyroidism in a Patient With Sarcoidosis: A Case Report. Cureus, 16(9), e69504. https://doi.org/10.7759/cureus.69504 2. Ackermann D. Die Hyperkalzämie im Verlauf der Sarkoidose--Fallbeispiel, Prävalenz, Pathophysiologie und Therapiemöglichkeiten [Hypercalcemia in sarcoidosis--case report, prevalence, pathophysiology and therapeutic options]. Ther Umsch. 2007 May;64(5):281-6. German. doi: 10.1024/0040-5930.64.5.281. PMID: 17685088. Presentation: Saturday, July 12, 2025