My 87 year old mother has non-alcoholic cirohsis of the liver with portal vein hypertension ans esophageal varicies. She also has an artificial aortic valve. She fell and struck her head causing a hematoma and small bleed to the frontal lobe. There were no physical or mental deficits. Since hospitalization, they have increased her lactalose from 5ml (1 tsp.) bid to 22.5ml tid. in a 10 day period. What has caused such a large increase in the ammonia level in her blood over such a short period of time?