Profound Tacrolimus-Induced Catatonic Encephalopathy in a Kidney Transplant Recipient With Mitochondrial Myopathy: A Cautionary Case of Reversible Neurotoxicity.

INTRODUCTION: Maternally inherited diabetes and deafness (MIDD) is a multisystem mitochondrial disorder most commonly caused by the m.3243A>G pathogenic variant in the MT-TL1 gene. Kidney transplantation in affected individuals presents unique perioperative and immunosuppressive management challenges due to underlying metabolic, neurologic, cardiac, and neuromuscular vulnerability.

CASE REPORT: We report a 64-year-old woman with end-stage renal disease secondary to insulin-dependent diabetes and MIDD (m.3243A>G) who underwent unrelated living donor kidney transplantation. The immediate postoperative period was complicated by diabetic ketoacidosis with lactic acidosis, transient slow graft function, and profound encephalopathy with catatonic features. Neuroimaging showed no acute abnormalities, and electroencephalography demonstrated severe diffuse encephalopathy without epileptiform activity. Tacrolimus levels were supratherapeutic in the early postoperative period. Given concern for calcineurin inhibitor neurotoxicity superimposed on mitochondrial dysfunction, tacrolimus was discontinued, and immunosuppression was switched to cyclosporine. Neurologic status gradually improved, and kidney allograft function fully normalized.

DISCUSSION: This case highlights the substantial perioperative metabolic and neurologic risks associated with kidney transplantation in patients with MIDD. Patients with compensated cardiac dysfunction and manageable neuromuscular impairment should not be excluded from transplantation solely on the basis of mitochondrial cytopathy.