A nurse is assessing a client who recently began taking fluphenazine. Which of the following findings should the nurse identify as a manifestation of neuroleptic malignant syndrome?

Choice A reason: Decreased temperature is not a manifestation of neuroleptic malignant syndrome (NMS). In fact, NMS is characterized by hyperthermia due to severe muscle rigidity and autonomic dysfunction. A low temperature would not align with the pathophysiology of this condition. Choice B reason: Bradycardia is not typical of NMS. Instead, clients often present with tachycardia due to autonomic instability. Bradycardia would suggest another underlying condition rather than NMS. Choice C reason: Muscle rigidity is a hallmark symptom of NMS. It results from dopamine blockade in the central nervous system caused by antipsychotic medications such as fluphenazine. Severe rigidity contributes to hyperthermia and can lead to rhabdomyolysis, making this the most critical finding to identify. Choice D reason: Hyperthermia is indeed a classic feature of NMS, but in this question, the most defining and diagnostic manifestation is muscle rigidity. Hyperthermia occurs as a consequence of rigidity and autonomic dysfunction, but rigidity is the primary sign that distinguishes NMS from other conditions.