A nurse is caring for a patient who recently began treatment with haloperidol. The patient suddenly develops a high fever, muscle rigidity, altered mental status, and sweating. Which of the following should the nurse suspect?

Rationale: A. Serotonin syndrome presents with similar symptoms (e.g., hyperthermia, agitation, neuromuscular abnormalities), but it is usually associated with serotonergic medications (e.g., SSRIs, SNRIs), not antipsychotics like haloperidol. B. Tardive dyskinesia involves involuntary, repetitive movements (e.g., lip smacking, tongue protrusion), but not fever or altered mental status. C. Neuroleptic Malignant Syndrome (NMS) is a rare but life-threatening reaction to antipsychotics like haloperidol. Key features include high fever, "lead pipe" muscle rigidity, altered mental status, and autonomic instability (e.g., diaphoresis, fluctuating blood pressure). D. Extrapyramidal side effects (EPS) include akathisia, dystonia, and parkinsonism—these do not typically involve fever or altered consciousness.