A nurse is reviewing a patient's medication list and notes the patient is taking haloperidol. The nurse should assess the patient for which serious adverse effect associated with this typical antipsychotic?

Introduction: Haloperidol is a high-potency first-generation antipsychotic that acts as a dopamine D2 receptor antagonist. While effective for schizophrenia and acute psychosis, it carries a high risk for Extrapyramidal Symptoms (EPS) and the rare, life-threatening idiosyncratic reaction involving severe dysregulation of the autonomic nervous system and skeletal muscle. A. Malignant hyperthermia is a pharmacogenetic disorder of skeletal muscle triggered by volatile inhalational anesthetics or succinylcholine. While it shares some symptoms with NMS (like fever and rigidity), it is a distinct condition related to ryanodine receptor mutations rather than dopamine blockade in the central nervous system. B. Akathisia is a common extrapyramidal side effect characterized by subjective feelings of inner restlessness and the urge to move. While distressing and a known side effect of haloperidol, it is not typically life-threatening. The nurse must differentiate between common EPS like akathisia and the more systemic, lethal complication of NMS. C. NEUROLEPTIC MALIGNANT SYNDROME (NMS) is a medical emergency associated with haloperidol. It is characterized by the "lead-pipe" MUSCLE RIGIDITY, HYPERTHERMIA, autonomic instability (tachycardia, diaphoresis), and altered mental status. It requires immediate discontinuation of the antipsychotic and intensive supportive care to prevent cardiovascular collapse or renal failure. D. Serotonin syndrome is a toxic state caused by an excess of serotonergic activity, usually from combining SSRIs, SNRIs, or MAOIs. While it also presents with fever and altered mental status, haloperidol is a dopamine antagonist, not a serotonin enhancer, making NMS the more relevant and expected serious complication for this medication