TERIPARATIDE USE IN THE TREATMENT OF SEVERE HYPOCALCEMIA AFTER KIDNEY TRANSPLANTATION: A CASE REPORT

Introduction: Teriparatide is a recombinant parathyroid hormone (PTH) analogue and a potent osteoanabolic agent. Intermittent teriparatide therapy increases the number of osteoblasts and subsequent bone formation. Teriparatide, like endogenous PTH, influences calcium and phosphate homeostasis by transiently increasing serum calcium levels and urinary calcium excretion. Methods: We report the use of teriparatide therapy in a patient who had previously undergone parathyroidectomy for severe and prolonged hypocalcemia after kidney transplantation. Results: A 30-year-old lady with end-stage kidney disease secondary to chronic glomerulonephritis on hemodialysis for 14 years underwent a deceased donor kidney transplant in October 2021. She had total parathyroidectomy 9 years prior for tertiary hyperparathyroidism and was on alpha calcidol 3 mcg every other day and calcium carbonate 1.5 g three times daily. Pretransplant calcium and phosphate levels were normal and her iPTH level was <5.5 pg/ml. She received basiliximab induction followed by tacrolimus, mycophenolate mofetil and prednisolone as maintenance immunosuppression with immediate graft function. She developed hypocalcemia in the immediate postoperative period requiring increased doses of oral and intravenous calcium supplements and oral vitamin D for 16 days; despite this, calcium remained low and she was persistently symptomatic. Subcutaneous teriparatide 20 mcg twice daily was started on day 17. Serum calcium normalized two days after teriparatide initiation, allowing cessation of intravenous calcium and reduction of oral calcium and vitamin D. After discharge, teriparatide was reduced to 20 mcg daily for two weeks and then stopped due to hypercalcemia. Calcium levels remained stable thereafter with low doses of oral calcium and vitamin D. Phosphate levels declined and serum creatinine remained stable; no adverse events related to teriparatide occurred. Conclusions: Refractory hypocalcemia after kidney transplantation in patients with low PTH can be successfully treated with teriparatide, enabling faster normalization of calcium, earlier cessation of intravenous calcium therapy, and reduced calcitriol requirements, potentially decreasing pill burden and hospitalization despite higher cost.