Pain syndrome with stress fractures in transplanted patients treated with calcineurin inhibitors.

Bone disease remains a major cause of morbidity after renal transplantation. Post-transplant osseous complications include osteoporosis and osteonecrosis, both historically associated with glucocorticoids, and a newer syndrome of bone pain associated with calcineurin inhibitors. Calcineurin inhibitor-induced pain syndrome (CIPS) is a reversible etiology of lower extremity bone pain and bone marrow edema reported in patients receiving cyclosporine or tacrolimus after solid organ or bone marrow transplantation. While the syndrome's pathophysiology is unclear, bone insufficiency and epiphyseal impaction may play a role. We review the literature on this increasingly important post-transplant entity and describe a case illustrating the syndrome's key features.