A client with schizophrenia returns to the clinic two weeks after receiving a prescription for haloperidol. To assess for neuroleptic malignant syndrome (NMS), which information is most important for the nurse to obtain during this visit?

Neuroleptic Malignant Syndrome (NMS) is a life-threatening reaction to antipsychotics like haloperidol. Its hallmark signs are autonomic instability, including hyperthermia (high fever), tachycardia, tachypnea, and labile blood pressure. Obtaining current vital signs is the most critical and immediate assessment to detect these key indicators. While an elevated white blood cell count (C) can occur with NMS, it is a secondary laboratory finding, not the primary clinical assessment. Blood sugar (A) and 24-hour urinary output (D) are not characteristic assessments for NMS.