Síndrome doloroso por inhibidores de la calcineurina: reporte de 4 casos en pacientes con retrasplante renal

Introduction: Kidney transplant is the first-line therapy for chronic kidney disease. Immunosuppressants such as calcineurin-inhibitors may be associated with side effects. Calcineurin-inhibitor induced pain syndrome (CIPS) is characterized by symmetrical, severe and disabling bone pain in the lower limbs and can be easily identified by magnetic resonance imaging due to its typical patterns. Four CIPS cases after kidney retransplantation are presented, confirmed by MRI and with immunosuppressive therapy consisting of tacrolimus. Methods: Four patients (3 females and 1 male) with cadaveric kidney retransplantation, performed between March 2014 and September 2015 showed intense pains in their lower limbs. Tacrolimus was the main immunosuppressive agent. MRI scans of the lower limbs were performed; tacrolimus treatment and dosage adjustment were indicated. Results: CIPS started 2 months after transplantation and 2 weeks after detection of tacrolimus toxic levels. Pain lasted around 2 weeks and it gradually became less severe. Symptoms were exclusively located in the lower limbs (knees, ankles and feet). Patients described the pain as sharp, throbbing, disabling, and becoming worse when standing. MRI confirmed the diagnosis, revealing a pattern of bone marrow edema in tibial plateau and tali. All cases were reversible with the indicated treatment. Conclusions: This study registers 4 cases of CIPS in patients who had undergone kidney retransplantation and had taken tacrolimus with good response. Diagnosis was reached by clinical suspicion, form and location of pain, and characteristic patterns in the MRI scans.