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Abstract Disclosure: M. Vahidi Rad: None. S. Ahmed: None. A. Kumar: None. Introduction: Granulomatous disease can cause hypercalcemia due to increased production of 1,25 dihydroxyvitamin-D. Mycobacterium avium complex (MAC) infection is an AIDS (acquired immunodeficiency syndrome)-defining illness and a granulomatous disease that can lead to hypercalcemia. We report a case of severe hypercalcemia from Immune Reconstitution Inflammatory Syndrome (IRIS) in a patient with AIDS and disseminated MAC which developed several months after initiation of appropriate antibiotic and antiviral therapy. Clinical Case: A 30-year-old female with HIV on anti-retroviral therapy and disseminated MAC infection on antibiotics developed PTH independent mild hypercalcemia in the 10.9-11.5 mg/dL range about 4 months after initiation of antiviral and antibiotic therapy. 1,25 dihydroxyvitamin D level was normal at 50 pg/mL (reference range 18-78 pg/mL). The hypercalcemia worsened and about 8 months after initiation of antimicrobial therapy, she had a hospitalization for severe hypercalcemia with corrected calcium of 15.2 mg/dL and acute kidney injury. PTH was suppressed at 6.9 pg/mL and repeat 1,25 dihydroxyvitamin D level was elevated at 129 pg/mL (reference range 18-78 pg/mL). Other testing for PTH independent hypercalcemia including PTH- Related Peptide, serum protein electrophoresis (SPEP) and TSH were normal. She was diagnosed with hypercalcemia from increased calcitriol production in the setting of IRIS secondary to disseminated MAC. Hypercalcemia secondary to increased production of calcitriol in patients with MAC and HIV infection might happen or worsen months after starting the antimicrobial treatments and has been reported as a potential manifestation of immune reconstitution. MAC-associated IRIS has been reported to be associated with a T-helper cell response with increased number of interferon-gamma-producing T-cells and Th1-cytokines that can potentially cause a granulomatous reaction. These granulomas will have increased macrophage 1-alpha-hydroxylase activity that can further result in more production of 1,25 dihydroxyvitamin D3 and cause more hypercalcemia. Prednisone was started with resultant improvement in hypercalcemia. Conclusion: Severe hypercalcemia due to worsening of subclinical granulomatous infections such as MAC can be a manifestation of IRIS in patients with HIV infection or AIDS who are on antiretroviral treatments. This responds to glucocorticoids. Presentation: 6/2/2024
Rad et al. (Tue,) studied this question.