Which lab result would best explain hepatic encephalopathy signs such as disorientation and asterixis?

• A. Decreased magnesium level
• B. Increased calcium level
• C. Increased ammonia level
• D. Increased creatinine level

Answer: (C)

Elevated ammonia level best explains hepatic encephalopathy signs. When the liver is damaged, it can’t effectively convert ammonia into urea, so ammonia builds up in the bloodstream. Ammonia crosses into the brain and disrupts neurotransmission, leading to confusion, disorientation, and motor findings like asterixis. The other options don’t directly drive the neuropsychiatric symptoms seen with hepatic encephalopathy—low magnesium can cause neuromuscular issues but not the characteristic cognitive changes; high calcium isn’t the typical driver; and increased creatinine points to kidney dysfunction, which can worsen overall illness but isn’t the primary cause of hepatic encephalopathy.