New-onset Psychosis in an Immunosuppressed Patient With Kidney Transplantation: An Educational Case Report

RATIONALE: New-onset psychosis in an immunosuppressed patient post-kidney transplantation (KT) is a diagnostic challenge. A broad differential diagnosis merits consideration; however, an approach to this differential diagnosis remains to be outlined in the literature. Also, when and how to modify the maintenance immunosuppressive regimen remains a significant area of controversy. PRESENTING CONCERNS: A 23-year-old male, known for X-linked Alport syndrome for which he had undergone KT 1 year prior, presented with a 1-week history of disorganized speech, bizarre behavior, religious delusions, and visual hallucinations. DIAGNOSES: After ruling out infectious, metabolic, autoimmune, and structural causes, immunosuppressant medications were changed from tacrolimus to cyclosporine. The patient did not improve after this change, and a second opinion consultation with a transplant psychiatrist led to a diagnosis of primary first-episode psychosis, later refined to bipolar disorder type I. INTERVENTIONS: The patient was started on risperidone, which led to a significant improvement in his symptoms. OUTCOMES: Twelve months after discharge, his mood and behavior had returned to baseline on aripiprazole, bupropion, and citalopram. However, he developed acute allograft rejection, prompting a change from cyclosporine back to tacrolimus, with stability of his mental state and graft function. TEACHING POINTS: This report offers learners an extensive and organized differential diagnosis to the work up of psychosis post kidney transplantation. A complete history, with input from collateral sources, and a systematic approach to the differential diagnosis, are crucial and should not be overshadowed by the risk of immunosuppressant-related neurotoxicity. We underscore the importance of multi-disciplinary management and comprehensive psychosocial assessment and re-assessment to refine the diagnosis. We also report the successful re-introduction of tacrolimus once the diagnosis of a primary psychiatric disorder is confirmed. Finally, we offer a simplified approach that can aid in distinguishing between a primary psychiatric diagnosis versus tacrolimus-associated psychosis.