Pain syndrome induced by calcineurin inhibitor and resolved by conversion to sirolimus in a child after kidney transplantation: a case report.

Pain induced by calcineurin inhibitors is a rare complication of unknown pathogenesis. We have reported herein a 7-year-old child who presented with abdominal pain, vomiting, and weight loss showing no significant findings after an extensive laboratory and imaging workup. After conversion from tacrolimus to sirolimus, there was complete resolution of the gastrointestinal symptoms and pain; the patient displays excellent renal function. Calcineurin inhibitor-induced pain syndrome is diagnosis of exclusion but must be considered because the withdrawal of this immunosuppressive agent is associated with improvement in symptoms and quality of life.