Calcitriol-Mediated Hypercalcemia from Hepatic Granulomatosis Following Percutaneous Cholecystostomy Tube

Abstract

Granulomatous conditions can present with calcitriol-mediated hypercalcemia via increased 1-hydroxylase activity—activity that is not inhibited by calcium or calcitriol—indicating a lack of feedback inhibition. Differential diagnosis of granulomatosis is quite broad and can require extensive workup as highlighted by this case. Our patient is a 69-year-old white female admitted to the hospital with altered mental status and hypotension. Initial evaluation was concerning for infection, due to leukopenia and thrombocytopenia. CT abdomen revealed cholecystitis, percutaneous cholecystostomy tube was placed, and the patient’s mental status improved. One month after discharge, the patient presented to the hospital with a corrected calcium of 15.2 mg/dl. PTH was 22 pg/mL with normal renal function and phosphorus. The patient was treated with intravenous fluids, calcitonin, and zoledronic acid. Calcitriol was 69 pg/ml (18–75 pg/ml) and corrected calcium responded by time of discharge. During outpatient follow up, she was found to have corrected calcium 11.2 mg/dl and calcitriol 166 pg/ml with appropriately low PTH. Additional workup of apparent calcitriol-mediated hypercalcemia with whole-body CT imaging, tuberculosis screening, and flow cytometry only notable for possible right cervical lymphadenopathy on CT. Subsequent lymph node biopsy was benign. The patient completed a 30-day course of prednisone 20 mg daily followed by prednisone taper and her corrected calcium and calcitriol levels normalized. However, after discontinuation of prednisone, lab work demonstrated increase in calcium and liver enzymes. Repeat CT scan showed multiple hypoechoic areas with subsequent biopsy consistent with necrotizing hepatic granulomatosis. PAS-A, Fite, and AFB stains were negative for fungi and mycobacteria. Removal of cholecystostomy tube resulted in complete resolution of hypercalcemia and elevated calcitriol levels. Foreign body-induced granulomatosis is associated with PTH-independent hypercalcemia. Silicone has been implicated in foreign body granuloma. Hepatic granulomatosis is associated with percutaneous tube, especially with prolonged placement (approximately 11 months in this case). Removal of the foreign body is associated with improvement in hypercalcemia. Follow-up liver ultrasound demonstrated complete resolution of hepatic granulomas at three months following removal of the cholecystostomy tube.