SUN-795 Hypercalcemia in a Case of Coccidiomycosis

Abstract Disclosure: A. Risbud: None. A. Miller: None. K. Kirkeby: None. Background: Coccidioidomycosis, also known as Valley Fever, is caused by a dimorphic fungus endemic to arid regions of the western and southwestern United States. Immunocompromised patients are at higher risk of disseminated coccidioidomycosis. Hypercalcemia is an uncommon but known complication of disseminated infection. Clinical case: A 48-year-old woman living in central California presented with fever, shortness of breath, and left-sided pleuritic chest pain. Her past medical history included hypertension; hereditary nonpolyposis colorectal cancer (HNPCC); and chronic kidney disease due to focal segmental glomerulosclerosis (FSGS), for which she had undergone left renal transplantation 12 years prior and was now on chronic immunosuppression (including prednisone). She was found to have respiratory failure secondary to left lobar pneumonia with parapneumonic effusion requiring video-assisted thoracoscopic surgery (VATS) with decortication and lung biopsy. Biopsy showed marked necrosis with acute and chronic inflammation. GMS stain revealed Coccidioides immitis. She was treated with fluconazole for a few days before switching to isavuconazonium sulfate.During her hospitalization, she was also found to have hypercalcemia, with corrected serum calcium up to 14.7 mg/dL. Workup showed a low PTH, normal 25-hydroxyvitamin D, elevated 1,25-dihydroxyvitamin D, and high-normal PTHrP levels. There was a partial response to IV hydration. She was subsequently treated with pamidronate 30 mg IV, calcitonin 150 mg SC every 8 hours for 2 days, and prednisone 20 mg/day. Her serum calcium continued to rise 10-15 days after initiation of antifungal therapy, so prednisone was increased further, eventually up to 60 mg/day. She was then treated with denosumab 120 mg SC, and her calcium improved to 11.7 mg/dL. There was eventual improvement in her serum calcium levels, so her prednisone dose was gradually tapered while antifungal therapy continued. Conclusion: Multiple mechanisms of hypercalcemia in coccidioidomycosis have been proposed, including granuloma formation and increased PTHrP expression. As such, various treatment strategies - including hydration, bisphosphonate therapy, corticosteroids, may be employed, particularly in cases of refractory hypercalcemia despite antifungal therapy. References: Miranda, N., & Hoyer, K.K. (2023). Coccidioidomycosis Granulomas Informed by Other Diseases: Advancements, Gaps, and Challenges. Journal of Fungi, 9(6), 650.Yu, T., Bruce, S., Nguyen, D., Patel, A., & MacElwee, M. (2024). The Use of Steroids to Treat Hypercalcemia Due to Granulomatous Disease From Disseminated Coccidioidomycosis. Cureus, 16(7). Presentation: Sunday, July 13, 2025