A case of bone pain following kidney transplant: Differentiating between tertiary hyperparathyroidism and calcineurin-induced pain syndrome in post renal transplant patients

Metabolic derangements affecting bone health are undeniably common among patients who have undergone renal transplants. Due to long-standing chronic kidney disease (CKD), secondary hyperparathyroidism (SHPT) and tertiary hyperparathyroidism (THPT) are frequently observed in renal transplant patients and account for the bone disorders associated with this patient population, termed chronic kidney disease-mineral and bone disorders (CKD-MBD). As calcineurin inhibitors become increasingly commonplace in the long-term management of graft rejection, another process must be considered when working up a patient's bone pain. Calcineurin inhibitor-induced pain syndrome (CIPS) is a condition of episodic bone and articular pain that can present similarly to THPT with the presence of hypercalcemia, hyperphosphatemia and elevated alkaline phosphatase. However, CIPS can be distinguished from these other processes through its distinct imaging findings, with bone marrow and soft tissue edema on MRI and increased radiotracer uptake on bone scans. Here, we present a case of bone pain in a patient following renal transplant and the subsequent workup performed to identify the underlying process. As more and more patients undergo renal transplant and begin immunosuppression with calcineurin inhibitors, there is an increasing need for a thorough workup of bone pain and high clinical suspicion of CIPS. Furthermore, the debilitating pain associated with CIPS can be improved with reduction in immunosuppressive dosing; thus, having a high clinical suspicion for this condition can make a significant impact on patient quality of life as well as medical management of graft rejection immunosuppression.