Neuroleptic Malignant Syndrome in Patients With Dementia: Experiences of A Single Memory Clinic

Abstract

Objectives Neuroleptic malignant syndrome (NMS) is a life-threatening condition that occurs as an adverse reaction to antipsychotic and antiemetic agents or sudden withdrawal of dopaminergic medications. Given the metabolic and functional reserves and the comorbidities in older adults, NMS may show an atypical course. Methods The medical records of patients with neurodegenerative diseases leading to dementia between 2013 and 2020 were reviewed for the diagnosis of NMS. Demographic and clinical characteristics of the patients were obtained from the records of laboratory parameters, management, and length of stay. Results Fifteen older adults (19 episodes) diagnosed with NMS were included. The median age was 76 years, and 5 were female. Ten of 15 NMS patients were atypical. Most of them had an infection accompanying NMS. Neuroleptic malignant syndrome was caused by antidopaminergic agents (5 antipsychotics, 1 metoclopramide) in 6 episodes and discontinuation of a dopaminergic agent, l-DOPA, in 12 episodes. In 1 patient, it was associated with simultaneous use of domperidone and amantadine withdrawal. Rigidity in NMS due to l-DOPA discontinuation was higher than in those due to antipsychotic use (P = 0.027). Two of our patients needed intensive care, and 1 died. Conclusions This study highlights the high frequency of atypical NMS and the importance of early recognition of this potentially fatal syndrome, which can accompany neurodegenerative diseases and infections in older adults.