A 7-year-old boy is brought to the emergency department with confusion, vomiting, and lethargy. His symptoms started a few days after recovering from a viral illness, during which he was given aspirin for fever. On examination, he is drowsy but arousable. Laboratory tests reveal markedly elevated ammonia levels, hypoglycemia, and mild elevations in liver enzymes. There is no significant leukocytosis, and bilirubin levels are normal. Which of the following is the most likely diagnosis?
