A nurse is assessing a client who is receiving treatment with multiple antipsychotic medications and who suddenly became ill. Findings include blood pressure changes, hyperpyrexia, and diaphoresis. The nurse should recognize that which of the following adverse effects may be occurring?

Choice A reason: Pseudoparkinsonism causes symptoms such as tremors, rigidity, bradykinesia, and shuffling gait. It is not associated with fever, blood pressure changes, or diaphoresis. Choice B reason: Tardive dyskinesia develops gradually after prolonged antipsychotic use and presents with involuntary movements like lip smacking, tongue protrusion, or grimacing. It does not cause acute systemic symptoms such as hyperpyrexia or autonomic instability. Choice C reason: Neuroleptic malignant syndrome (NMS) is a life-threatening emergency associated with antipsychotics. It manifests with hyperpyrexia, autonomic instability (blood pressure changes, diaphoresis), severe muscle rigidity, and altered mental status. The client’s presentation matches NMS. Choice D reason: Acute dystonia involves sudden muscle contractions affecting the face, neck, or back (e.g., torticollis, oculogyric crisis). It does not present with systemic symptoms like fever or blood pressure fluctuations.