الفهرس 
PHYSIOLOGY OF LIVER METABOLISMيوجد فقط 14 صفحة متاحة للعرض العام
 |  | from | 114 |  |  |
| | | from | 114 | | |
المستخلص
Malnutrition is one of the most common problems seen in patients with hepatic encephalopathy. For morbidity, it is mandatory to be reduced and survival to be maximized. It is essential to assess nutritional status and maintain optimal nutrition in patients with liver diseases. Those with hepatic failure may gain weight due to fluid retention; this makes body weight measurement unreliable. Nevertheless, anthropometric measurements are still a useful way to assess subcutaneous fat and muscle mass. The most common methods for assessing nutritional status of these patients are: triceps skinfold thickness, mid-arm muscle circumference and 24-hour urinary creatinine execretion. In addition, there are several indirect methods used to assess body composition in clinical practice such as bioelectrical impedance analysis, total body potassium, dual-energy X-ray absorptiometry and isotopic dilution.
Although, use of indirect calorimetry is highly recommended to measure the resting energy expenditure, precisely, calculating it using the prediction equations such as Harris-Benedict equation can be used when the indirect calorimeter is not available.
Patients should eat 6 to 7 small meals per day with one late evening snack rich in carbohydrates and/or oral supplement with branched-chain amino acids (BCAAs); A practice which is shown to improve nitrogen retention and decrease undue catabolism.
Enteral nutrition (EN) is well-tolerated in patients with liver failure and not even contraindicated in malnourished patients and the delay of its initiation is associated with increased morbidity. Parenteral nutrition should be instituted whenever EN is inadequate, contraindicated or not tolerated. It could be also used with hepatic encephalopathy (HE).
Protein restriction continues in clinical practice despite evidence showing that patients with hepatic failure tend to be hypermetabolic, and a higher-than-normal supply of dietary proteins is needed to achieve nitrogen balance. In fact, most patients tolerate a normal or even increased dietary protein intake without risk of HE and, in malnourished patients, standard amino acid supplements should be considered to provide the necessary amount of proteins. In patients intolerant to the required protein intake due to HE, BCAAs supplements are considered to provide the recommended daily protein intake (1.0-1.5 gm/kg/day) without detrimental effects on the preferential use of vegetables rather than animal proteins.
Preliminary evidence supports the use of several nutriceuticals as diet supplements in liver failure for which conventional therapies are limited. They include: vitamins A,K,E,D,C,B12, folate, thiamine and carotenes, zinc, BCAAs, branched-chain ketoacids, ammonia-lowering agents such as arginine and glutamine and silymarin.
Protein-energy malnutrition is very common in chronic liver disease and negative nutrient balance due to inadequate intake is frequent. Thus, instead of imposing restrictive diets, which may be harmful, the goal of nutritional therapy is to ensure adequate provision of energy, nitrogen and micronutrients to improve nutritional status.