ODP094 Hypercalcemia caused by Mycobacterium Avium Complex, with Excellent Response to Intravenous Pamidronate.

Abstract

Abstract Background Hypercalcemia caused by granulomatous diseases such as sarcoidosis and tuberculosis, is a well-recognized entity. The pathophysiology of hypercalcemia associated with granulomatous diseases is related to increase conversion of 25 hydroxyvitamin D to its active form, 1,25 dihydroxyvitamin D, via extra-renal 1 -α hydroxylase activity. We present a patient with moderately sever hypercalcemia caused byMycobacterium Avium complex (MAC) infection in association with Human Immunodeficiency Virus (HIV) infection. Case Presentation The patient is 53-year-old male with longstanding HIV infection since 2003. He was referred to the endocrine clinic after an acute presentation to a local hospital in August 2021 with pancytopenia, lymphadenopathy, and hypercalcemia (corrected total calcium 13.8 mg/dl) with acute kidney injury. He was treated with intravenous fluids and subcutaneous Calcitonin injection. Endocrine work up showed low parathyroid hormone (PTH) at 3 pg/ml (14-95 pg/ml) and Parathyroid related peptide (PTHrP) level was <0.4 pmol/l. His 1,25 dihydroxy-vitamin D was elevated at 172 pg/ml (18-64 pg/ml) . Computed Tomography (CT) study for neck, chest and abdomen showed hepatosplenomegaly, generalized lymphadenopathy involving the left cervical area, left supraclavicular area, mediastinal, retroperitoneal, mesenteric and inguinal lymphadenopathy. Bone marrow study from August 2021 showed no evidence of leukemia, lymphoma, tuberculosis or other bone marrow inflammatory or infiltrative processes. Left sided neck lymph node biopsy showed diffuse granulomatous disease and numerous acid-fast organism consistent with Mycobacterium Avium complex (MAC) He was treated with azithromycin 250 mg daily, ethambutol 1200 mg daily, and rifabutin 300 mg daily in addition to anti-retroviral therapy (bictegravir/emtricitabine/tenofovir). Hypercalcemia was treated with one dose of pamidronate 90 mg which normalized serum calcium within one week. Glucocorticoids was not considered due to concerns over sever immunosuppression due to HIV/ AIDS and pancytopenia. Denosumab, ketoconazole and hydroxychloroquine were also not considered due to concerns over side effects. His 1,25 dihydroxy-vitamin D level normalized after four months from starting treatment with anti MAC therapy. Most recent calcium level 9.1 mg/dl, with 1,25 dihydroxy-vitamin D level of 31 pg/ml. Conclusion Mycobacterium Avium Complex infection is a possible cause of hypercalcemia, especially in immunocompromised individuals. Glucocorticoids, usually the first line treatment for acute hypercalcemia induced by 1,25 dihydroxyvitamin D overproduction, might not be appropriate in all patients. Alternatives include hydroxychloroquine, ketoconazole and parenteral bone anti- resorptive agents. Our patient had an excellent response to one dose of pamidronate. Ultimately his1,25 dihydroxy-vitamin D normalized with effective anti MAC therapy. Presentation: No date and time listed