A patient is experiencing muscle rigidity and altered mental status while taking haloperidol. What complication should the nurse suspect?

Choice A reason: Tardive dyskinesia is a late-onset complication of long-term neuroleptic use characterized by involuntary, repetitive movements of the tongue, face, and extremities, such as lip-smacking. It does not typically present with acute "lead-pipe" muscle rigidity or a rapidly deteriorating mental status seen in emergency situations. Choice B reason: Neuroleptic Malignant Syndrome is a life-threatening idiosyncratic reaction to antipsychotics. It is characterized by the clinical tetrad of mental status changes, generalized muscle rigidity, hyperpyrexia (fever), and autonomic instability. Given the patient is taking haloperidol, a high-potency first-generation antipsychotic, these symptoms constitute a medical emergency requiring immediate attention. Choice C reason: Agranulocytosis is a severe reduction in the white blood cell count, specifically neutrophils, which increases the risk of life-threatening infections. While it is a serious side effect of certain antipsychotics like clozapine, it presents with signs of infection like fever and sore throat, not muscle rigidity. Choice D reason: Akathisia is a common extrapyramidal side effect characterized by a subjective feeling of inner restlessness and an inability to sit still. While distressing, it does not involve the severe muscle rigidity or altered consciousness that defines the more dangerous Neuroleptic Malignant Syndrome seen in this patient.