Delirium Mistaken for Bipolar Disorder in a Paediatric Oncology Patient: A Case Report.

Delirium is a clinically significant complication in paediatric oncology that often leads to diagnostic delays. This case describes a 12-year-old boy with high-risk B-cell acute lymphoblastic leukaemia who developed acute neuropsychiatric symptoms, including agitation, hallucinations, seizures, and fluctuating mood states. Initially misdiagnosed with paediatric bipolar disorder, the patient was treated with antipsychotics and sedatives with limited effects. Notably, the hyperactive symptoms transitioned to a hypoactive state following the discontinuation of meropenem. This case illustrates the diagnostic challenges in distinguishing delirium from psychiatric disorders in paediatric settings, especially in the context of complex medical treatments. The case highlights the need for greater clinical awareness, routine delirium screening using validated tools, and careful evaluation of the neurotoxic potential of multiple medications in paediatric oncology patients.