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

Teriparatide, a recombinant PTH analogue, is an osteoanabolic therapy that transiently raises serum calcium and affects calcium-phosphate homeostasis. Severe, prolonged hypocalcemia can occur after kidney transplantation, particularly in patients with low PTH levels following prior parathyroidectomy. The report explores whether teriparatide can correct refractory post-transplant hypocalcemia in this context and reduce reliance on intravenous calcium and high-dose vitamin D.

Single-patient case report. A 30-year-old woman with ESKD due to chronic glomerulonephritis, on hemodialysis for 14 years, received a deceased-donor kidney transplant (October 2021). Past history included total parathyroidectomy 9 years earlier for tertiary hyperparathyroidism; home medications included alfacalcidol 3 mcg every other day and calcium carbonate 1.5 g three times daily. Pre-transplant calcium and phosphate were normal; iPTH <5.5 pg/ml. Induction immunosuppression: basiliximab; maintenance: tacrolimus, mycophenolate mofetil, prednisolone; graft function was immediate. Post-operatively she developed symptomatic hypocalcemia requiring escalating oral and intravenous calcium and vitamin D for 16 days without normalization. On postoperative day 17, teriparatide 20 mcg subcutaneously twice daily was initiated. Two days after initiation, intravenous calcium was stopped and oral calcium/vitamin D were reduced. After discharge, teriparatide was reduced to 20 mcg daily for two weeks and then discontinued due to hypercalcemia; ongoing management with low-dose oral calcium and vitamin D followed. Serial monitoring included serum calcium, phosphate, and creatinine.

- Persistent postoperative hypocalcemia despite 16 days of high-dose oral and intravenous calcium and vitamin D in a kidney transplant recipient with prior parathyroidectomy and very low iPTH (<5.5 pg/ml). - Initiation of teriparatide 20 mcg SC twice daily on postoperative day 17 normalized calcium within 2 days, allowing cessation of IV calcium and reduction of oral calcium and vitamin D. - After discharge, teriparatide was reduced to 20 mcg daily, continued for 2 weeks, then stopped due to hypercalcemia; thereafter calcium remained stable on low-dose oral supplements. - Phosphate levels declined and serum creatinine remained stable throughout. - No teriparatide-related adverse events were reported during treatment.

This case demonstrates that teriparatide can rapidly correct refractory hypocalcemia in post–kidney transplant patients with low PTH, such as those with prior parathyroidectomy. By mimicking endogenous PTH effects, teriparatide facilitated normalization of calcium within 48 hours, enabling discontinuation of intravenous calcium and reduction of calcitriol and calcium supplement burden. These outcomes suggest potential benefits in shortening hospitalization and improving patient convenience, even considering the higher drug cost. The transient hypercalcemia observed necessitated discontinuation after two weeks, highlighting the need for close monitoring and dose adjustments. Overall, teriparatide appears to be a viable rescue therapy in selected post-transplant patients with recalcitrant hypocalcemia.

Teriparatide is an effective and safe option to treat recalcitrant hypocalcemia following kidney transplantation in a patient with prior parathyroidectomy, enabling rapid normalization of calcium, reduction in intravenous calcium use, and decreased calcitriol requirements.

Findings derive from a single-patient case report. Teriparatide induced hypercalcemia after two weeks, necessitating discontinuation. Cost implications were noted but not systematically evaluated.