Atypical neuroleptic malignant syndrome in a geriatric palliative care patient: a case report and review of the literature

BACKGROUND: Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening adverse reaction to antipsychotic medications that carries significant diagnostic complexity in its atypical forms, particularly among elderly patients with polypharmacy and multiple comorbidities in whom the classic diagnostic criteria are frequently unmet. Timely recognition of atypical NMS is critical, as diagnostic delays are associated with increased morbidity and mortality even in clinically mild presentation. CASE PRESENTATION: We present a 71-year-old Caucasian male patient with schizophrenia on chronic risperidone and quetiapine therapy who developed atypical NMS following administration of haloperidol 64 drops for insomnia during hospitalization for urinary tract infection in a palliative care unit. The patient presented with low-grade fever (37.9 °C) and mildly elevated creatine kinase (600 U/L) without classic rigidity or autonomic instability. Due to unavailability of dantrolene and bromocriptine at the facility, the patient was successfully managed with intravenous diazepam and aggressive hydration therapy. Complete resolution of fever and normalization of creatine kinase levels were achieved with conservative management. CONCLUSION: This case highlights the importance of recognizing atypical NMS presentations in elderly patients and demonstrates that successful outcomes can be achieved with supportive care when first-line agents are unavailable.