Neuroleptic Malignant Syndrome in an Institutionalized Geriatric Patient Following Antipsychotic Switch to Quetiapine: A Fatal Outcome

Neuroleptic malignant syndrome (NMS) is a rare but potentially fatal condition characterized by hyperthermia, severe muscle rigidity, altered mental status, and autonomic dysfunction, associated with dopamine D₂-receptor antagonists. We present the case of a 76-year-old institutionalized male with multiple comorbidities who developed NMS four days after initiating quetiapine, following recent discontinuation of risperidone. The clinical picture included hyperthermia, generalized rigidity, trismus, disorientation, autonomic instability, leukocytosis, hypernatremia, and markedly elevated creatine kinase. Although serotonin syndrome was considered due to concurrent duloxetine use, it was clinically excluded. Despite early treatment with dantrolene and bromocriptine, the patient's condition deteriorated rapidly, culminating in renal failure, cardiovascular collapse, and death. This case underscores the diagnostic complexity and high mortality risk of NMS in elderly patients with polypharmacy, emphasizing the need for early recognition and prompt management to improve clinical outcomes.