Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 67

Liver size and blood flow are reduced with age. The mechanism underlying these changes is yet to be discovered, but increased fibrosis and inflammation may play a role. Enzymatic activity, necessary for oxidation and glucuronidation in hepatocytes, decreases with age, resulting in susceptibility to drug overdose. Drug clearance from the blood decreases with age; this is very important in managing pharmacotherapy for the elderly, as is the risk of polypharmacy.⁵⁵ Bile acid production is managed by hepatocytes and has a balanced amount of cholesterol and bile acids. Increased cholesterol level in the bile and decreased muscle tone of the gallbladder contribute to an increased risk of stone formation.⁵⁶

Pancreatic enzyme secretion decreases, but no significant effects were shown in fat, carbohydrate, and protein digestion in the elderly.⁵⁷

The prevalence of carcinogenesis increases along the entire GI tract with age. Mucosal irritation, inflammation, impaired antioxidant mechanisms, and genetically damaged epithelium in the GI tract play a role in excess carcinogenesis. GI tract–related cancers may cause symptoms such as constipation, early satiety, and bleeding in the early stages. If caught and treated early, they may be cured. Blood analysis of the stool is a rapid and easy screening test for colorectal cancers, and the sensitivity of this test is 82%. If positive, additional diagnostic testing is recommended regardless of age. Endoscopic screening of the colon is recommended every decade over the age of 50 by American Cancer Society guidelines. Most of the guidelines also add that screening can be stopped after the age of 80.⁵⁸