Atypical Neuroleptic Malignant Syndrome: Pitfalls and Challenges in the Delirious Substance Abuser

Introduction: A rare and atypical form of Neuroleptic Malignant Syndrome (NMS) can be a deceptive and life threatening condition if not diagnosed properly in acute and critical care settings. Methods: The management of a patient presenting with atypical NMS without prominent rigidity, but with extensive rhabdomyolysis after the administration of haloperidol and ziprasidone is described in this report. Results: Prompt recognition of atypical features of NMS was managed by intensive care unit admission, supportive care and pharmacotherapy, leading to a complete resolution of the syndrome and a favorable outcome verified by laboratory findings. Conclusion: Early stages and atypical features of NMS may be variable in presentation and clinical course. The absence of muscle rigidity may not rule out NMS. A strong clinical suspicion based on clinical history is crucial for early diagnosis and treatment. Termination of dantrolene therapy may not be necessary during rhabdomyolysis and elevated aminotransferase levels.