Hepatic encephalopathy

A 54-year-old woman is brought to the emergency department by her partner due to altered mental status for the last 2 days. According to her husband, the patient has become increasingly lethargic, disoriented, and agitated. The patient has a history of chronic hepatitis C infection that was diagnosed 14 years ago. She refused all treatment at that time. Temperature is 37.0°C (98.6°F), pulse is 98/min, and blood pressure is 104/74 mmHg. On examination, the patient is lethargic and oriented only to self. When her hands are outstretched in front of her and extended at the wrist, they exhibit a flapping tremor. The abdomen is nontender and mildly distended; shifting dullness to percussion is present. There is no nuchal rigidity. Stool occult blood is positive. Laboratory testing reveals the following findings:



The patient is started on emergent therapy for her symptoms. Which of the following best explains the pathophysiology of this patient’s current condition?