[Case report: Neuroleptic malignant syndrome and diagnostic difficulties]

Area of Science:

• Neuroscience
• Pharmacology
• Psychiatry

Background:

• Neuroleptic malignant syndrome (NMS) is a rare, potentially fatal adverse drug reaction associated with neuroleptic medications.
• Characterized by hyperthermia, muscular rigidity, autonomic dysfunction, and altered mental status; onset typically within the first week of treatment or dose escalation.
• Pathophysiology is linked to dopamine receptor blockade, though not fully understood.

Observation:

• A 55-year-old female with a history of psychosis experienced worsening psychiatric symptoms, treated with long-acting risperidone, escitalopram, and oxazepam.
• Initial symptoms of fever and altered mental status were initially attributed to infection, despite neuroleptic discontinuation.
• Pulmonary embolism diagnosis led to loxapine initiation and risperidone re-administration, preceding NMS suspicion due to hyperthermia, tremor, and rigidity.

Findings:

• Diagnosis of NMS was complicated by atypical presentation (minor rigidity), slow resolution, and initial treatment failure with dantrolene.
• The use of long-acting risperidone prolonged drug release, contributing to diagnostic uncertainty.
• Recurrence of NMS symptoms upon clozapine reintroduction confirmed the diagnosis, despite clozapine not being a primary NMS risk factor.

Implications:

• This case underscores the diagnostic challenges of NMS, particularly with atypical presentations and long-acting antipsychotics.
• Highlights the importance of considering NMS in patients on neuroleptics, even with variable symptoms or initial treatment resistance.
• Emphasizes the need for careful reintroduction of antipsychotics and prolonged monitoring due to potential delayed drug effects.