Delayed and Atypical Neuroleptic Malignant Syndrome Following Extended-Release Injectable Aripiprazole Use

Aim: Neuroleptic malignant syndrome (NMS) is an uncommon but life-threatening condition associated with antipsychotic medications that interfere with central dopaminergic pathways. While typically linked to highpotency antipsychotics like haloperidol, atypical antipsychotics such as aripiprazole can also induce NMS. The syndrome is characterized by hyperthermia, autonomic instability, altered mental status, and muscle rigidity, though atypical cases may lack some of these hallmark features. We aim to present an NMS case presented with delayed atypical symptoms following extended-release injectable (ERI) aripiprazole. Case Presentation: A 40-year-old female patient with bipolar disorder and major depression arrived at the emergency department complaining of decreased mental clarity, difficulty with swallowing solid food, and impairments in communication and mobility who received ERI aripiprazole 40 days prior to admission. Despite lacking rigidity, she exhibited motor jerks, autonomic instability, and a delayed elevation in creatine kinase levels. NMS was diagnosed after excluding other causes, but the patient deteriorated rapidly, developing acute renal failure, cardiovascular instability, and malignant arrhythmia, which led to death. Conclusion: This case highlights the potential for delayed and atypical presentations of NMS with ERI aripiprazole, emphasizing the need for clinicians to maintain a high index of suspicion for NMS, even when typical symptoms like rigidity are absent.