A client is receiving an inhaled anesthetic for anesthesia during surgery. The client's body temperature starts to rise, followed by sweating. The nurse recognizes these as early symptoms of which potentially fatal reaction to inhaled anesthetics?

A. Malignant hyperthermia: Malignant hyperthermia is a rare, life-threatening hypermetabolic reaction triggered by certain inhaled anesthetics and depolarizing neuromuscular blockers such as succinylcholine. Early signs include a rapid rise in body temperature, tachycardia, muscle rigidity, and diaphoresis. Prompt recognition and intervention with dantrolene and supportive measures are critical to prevent severe complications. B. Red man syndrome: Red man syndrome is an infusion-related reaction to rapid vancomycin administration, characterized by flushing, erythema, and pruritus, primarily affecting the upper body. It is not associated with hyperthermia or muscle rigidity, nor is it related to inhaled anesthetic agents. C. Local Anesthetic Systemic Toxicity (LAST): LAST results from excessive plasma concentrations of local anesthetics, leading to central nervous system and cardiovascular effects such as seizures, arrhythmias, and hypotension. While potentially serious, it does not present with generalized hyperthermia or sweating as early signs. D. Stevens-Johnson Syndrome: Stevens-Johnson Syndrome is a severe mucocutaneous reaction, often drug-induced, characterized by widespread epidermal necrosis, blistering, and mucous membrane involvement. It develops over days rather than minutes and is unrelated to anesthetic exposure or acute hyperthermia.