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Liver Failure

Liver failure is severe deterioration in liver function.

·         Liver failure is caused by a disorder or substance that damages the liver.

·         Most people have jaundice, feel tired and weak, and lose their appetite.

·         Other symptoms include accumulation of fluid within the abdomen (ascites) and a tendency to bruise and bleed easily.

·         Doctors can usually diagnose liver failure based on symptoms and results of a physical examination and blood tests.

·         Treatment usually involves controlling protein consumption, limiting sodium in the diet, completely avoiding alcohol, and treating the cause, but sometimes liver transplantation is required.

Liver failure can result from any type of liver disorder, including viral hepatitis, cirrhosis, and liver damage from alcohol or drugs such as acetaminophen.

A large portion of the liver must be damaged before liver failure occurs. Liver failure may develop rapidly over days or weeks (acute) or gradually over months or years (chronic).

Many effects occur because the liver malfunctions:

·         The liver can no longer adequately process bilirubin (a waste product formed when old red blood cells are broken down) so that it can be eliminated from the body. Bilirubin then builds up in the blood and is deposited in the skin. The result is jaundice.

·         The liver can no longer synthesize enough of the proteins that help blood clot. The result is a tendency to bruise and bleed (coagulopathy).

·         Blood pressure in the veins that bring blood from the intestine to the liver is often abnormally high (called portal hypertension).

·         Fluid may accumulate within the abdomen (ascites).

·         Brain function may deteriorate because the liver cannot remove toxic substances as it normally does. These substances build up in the blood and cause brain function to deteriorate. This disorder is called hepatic encephalopathy.

·         New veins (called collateral vessels) that bypass the liver may form. They often form in the esophagus and the stomach. There, the veins enlarge and become twisted. These veins—called varicose veins of the esophagus (esophageal varices) or stomach (gastric varices)—are fragile and prone to bleeding.

SYMPTOMS

People with liver failure usually have jaundice, ascites, hepatic encephalopathy, and generally failing health. Jaundice makes the skin and whites of the eyes look yellow. Ascites may cause the abdomen to swell. Hepatic encephalopathy may cause confusion or drowsiness. Most people also have general symptoms, such as fatigue, weakness, nausea, and loss of appetite. People may bruise and bleed easily. For example, bleeding that would be slight in other people (for example, bleeding from a small cut or a nosebleed) may not stop on its own and may even be difficult for doctors to control.

In acute liver failure, people may go from being healthy to near death within a few days. In chronic liver failure, the deterioration in health may be very gradual until a dramatic event, such as vomiting blood or having bloody stools, occurs. Blood in vomit or stool is usually caused by bleeding from varicose veins in the esophagus and stomach.

Ultimately, liver failure is fatal if it is not treated or if the liver disorder is progressive. Even after treatment, liver failure may be irreversible. Some people die of kidney failure (hepatorenal syndrome) because liver failure can eventually lead to kidney failure. Some people develop liver cancer.

DIAGNOSIS

Doctors can usually diagnose liver failure based on symptoms and the results of a physical examination. Blood tests are done to evaluate liver function, which is usually severely impaired. To check for possible causes, doctors ask about all substances that people have taken, including prescription and over-the-counter drugs, herbal products, and nutritional supplements. Blood tests are also done to identify possible causes.

TREATMENT

Treatment depends on the cause and the specific symptoms. The urgency of treatment depends on whether liver failure is acute or chronic, but the principles of treatment are the same.

People are usually placed on a restricted diet, limiting the amount of animal protein, particularly in red meat but also in fish, cheese, and eggs. Eating too much animal protein can contribute to brain dysfunction. To make sure people get enough protein, doctors advise them to eat more foods that contain vegetable protein (such as soy). People should also limit their consumption of sodium (in salt and many foods). Doing so can help prevent fluid from accumulating within the abdomen. Alcohol is completely avoided because it can worsen liver damage.

Liver transplantation if done soon enough, can restore liver function, sometimes enabling people to live as long as they would have if they did not have a liver disorder. However, liver transplantation is not suitable for all people with liver failure.

Nutrition and Liver disease

It is vitally important that patients with liver disease maintain a balanced diet, one which ensures adequate calories, carbohydrates, fats and proteins. Such a diet will aid the liver in the regeneration of liver cells. Nutrition that supports this regeneration is a means of treatment of some liver disorders.

Patients with cirrhosis, for example, who are malnourished, require a diet rich in protein and providing 2,000 - 3,000 calories per day to help the liver re-build itself. However, some cirrhotic patients have protein intolerance. Too much protein will result in an increased amount of ammonia in the blood, while too little protein can reduce healing of the liver. Doctors must carefully prescribe a specific amount of protein that will not elevate the blood ammonia. Lactulose and neomycin are two drugs that help keep the ammonia down.

It is believed that the risk of gallbladder disorders can be reduced by avoiding high fat and cholesterol foods and preventing obesity. The gallbladder is a storage sac for the bile produced by the liver. During digestion, the gallbladder releases bile into the small intestine through the common bile duct. Most gallbladder problems are caused by gallstones and 80-90% of all gallstones are produced from excessive cholesterol which crystallizes and forms stones. By maintaining a well-balanced diet and avoiding high cholesterol intake, the incidence of gallstone formation may be lowered.

When are specific diet restrictions required?

Beyond the maintenance of a good, well-balanced diet, several conditions that develop in the later stages of cirrhosis require specific dietary management.

·         hepatic encephalopathy

Hepatic encephalopathy is a condition of impaired mental function due to altered liver function. It is often seen when scar tissue formation (cirrhosis) in the liver prevents the normal flow of blood through the liver. The blood which contains toxins is “shunted” or redirected, back to the central circulation and into the brain without first going through the liver for detoxification. Cirrhosis with portal hypertension (an elevation of the portal pressure due to the obstruction of blood flow through the liver) may be treated surgically by shunting some of the blood around the liver, connecting the portal system with the systematic circulation. This “shunted” blood contains high concentrations of amino acids and ammonia and probably other, as yet unidentified, toxic substances that may cause altered mental function in some patients.

The treatment for hepatic encephalopathy is aimed at reducing toxins that cause this disorder. Just as patients with cirrhosis who have protein intolerance must restrict protein intake, so must patients with hepatic encephalopathy reduce the amount of protein in their diet. Severe protein restriction (to 20 grams a day or less) is impractical for long term therapy. Most physicians will encourage their patients to take approximately 40 grams of protein a day and will prescribe lactulose and neomycin to decrease the production of ammonia in the intestines. Certain specific amino acids (hepatamine) may be less likely to cause hepatic encephalopathy and have even been suggested as therapy. Certain foods (vegetables, milk) contain protein, rich in these amino acids and are preferred to meat as a source of protein in affected patients. A dietary supplement rich in these amino acids (hepatic-aid) is available and is in use in many liver centres.

·         ascites and edema

Ascites is the accumulation of fluid in the abdominal cavity. Edema is fluid built up in the tissues, usually the feet, legs or back. Both conditions result from abnormal accumulation of sodium associated with portal hypertension and liver disease. Most affected patients will not require strict fluid restriction. Sodium intake is often restricted for patients with cirrhosis to avoid retention of fluids in the body. Such a diet would allow only 2-4 grams of sodium and would exclude canned soups and vegetables, cold cut meats, condiments such as mayonnaise and ketchup, dairy products, cheese and ice cream. Most fresh foods are low in sodium. The best salt substitute is lemon juice (which is salt free).

·         cholestasis

Cholestasis is an inability of the liver to excrete bile. This may result insteatorrhea (fat malabsorption due to inadequate amounts of bile which dissolve fat in the intestines). Steatorrhea may go unnoticed by the patient or can be associated with weight loss due to lost calories. Stools may be foul smelling and float. Fat supplements are available; the most commonly used being medium chain triglycerides (MCT oil) and safflower oil which are absorbable with less dependence upon bile. They may be used as a caloric supplement. MCT oil is used like any other cooking oil, in salad dressings or in cooking. Patients with steatorrhea may also have difficulty absorbing fat soluble vitamins. However, water soluble vitamins are absorbed normally. Supplementing the diet with fat soluble vitamins is possible, though it should only be carried out under the guidance of a physician.

·         Wilson disease

In Wilson disease there is a defect in copper metabolism. Patients affected by this disorder have an abnormal build-up of copper in the body due to the inability of the liver to excrete it. This inability allows the copper to accumulate in several organs: first the liver and then, usually the brain and the cornea of the eye. Treatment involves the use of a de-coppering agent, penicillamine, which removes the excess copper from the body. Dietary therapy for this disease includes the avoidance of copper-containing foods like chocolate, nuts, shellfish and mushrooms.

·         hemochromatosis

Hemochromatosis is a disease in which there is an inappropriate absorption of iron from the intestine. The excessive iron then accumulates in the liver, pancreas and other organs in the body. Patients with this disease should not be given iron supplements. Aside from this precaution, those with hemochromatosis may follow a normal diet. Treatment is achieved by frequent removal of blood from a large vein.

·         fatty liver

Fatty liver is related to alcohol, obesity, starvation, some drugs and other factors. It is not caused by eating fat and it should be treated with a well-balanced diet or the removal of the responsible chemical substance or drug.

Finally, patients with liver disease should be wary of supplements to the diet, particularly fad foods or packaged “nutritional” aids. Such foods can contain a lot of salt, potassium or inappropriate protein mixtures. Those that are safe should be taken only under a physician’s guidance

Nutritional Support in Chronic Liver Disease

Treatment

The goals of nutritional therapy are to improve PCM and correct nutrient deficiencies. This can be accomplished via oral, enteral, or parenteral methods, or a combination of these modalities.

Intervention in the early stages of malnutrition can improve outcome. Hirsch et al. studied the effects of nutritional supplementation in patients with alcoholic cirrhosis.[47] They found that patients receiving a daily supplement of 1,000 kcal and 34 g of protein (given as a casein-based enteral nutrition product) had better outcomes compared with those in the control group; the number of hospitalizations was significantly fewer in the treated group, and additional parameters, including midarm circumference, serum albumin concentration, and hand-grip strength, also improved earlier in the treated group than in the control group. Mendenhall et al. studied the effects of oral nutritional support in patients with alcoholic hepatitis. In patients with severe malnutrition, inadequate caloric intake was associated with 51% mortality compared with 19% mortality in patients who received adequate oral nutrition (greater than 2,500 kcal/day).[48] One randomized, controlled trial demonstrated that providing nutritional supplementation to pretransplant candidates did not increase overall dietary energy or protein intake, and did not significantly improve post-transplant outcome. It is thought that the patients who received a nutritional supplement might have compensated for taking the supplement by decreasing their intake of food. This study concluded that regular dietary counseling is as effective in increasing energy intake as providing a nutritional supplement.[49]

As a general guideline, oral intake should be encouraged; if patients are unable to maintain adequate intake orally, a nasogastric tube should be inserted for enteral feeding. Cabre et al. found that, in severely malnourished patients with cirrhosis, enteral feeding improved serum albumin levels and Child-Turcotte-Pugh scores, and decreased in-hospital mortality rates, compared with the standard oral diet.[50] Hasse et al. demonstrated the benefit of early initiation of enteral feeding after transplantation.[51]Patients who received enteral feeds had an improved nitrogen balance and fewer viral infections after transplantation. Kearns et al. showed that aggressive nutritional intervention with enteral feeding accelerated improvement in alcoholic liver disease; patients who received enteral feeds demonstrated a more rapid decrease in bilirubin levels and improvement in hepatic encephalopathy compared with control participants.[52]

Parenteral nutrition is a less desirable option than enteral nutrition and should be reserved for patients in whom enteral feeding cannot be achieved.[53] Wicks et al. showed that enteral feeding is as effective as parenteral feeding for maintaining nutritional status after liver transplantation, and has the benefit of decreasing complications and cost.[54] There is some evidence to suggest that parenteral feeding might be superior to enteral feeding in patients with portosystemic shunting, because enteral feeding might worsen hyperammonemia in this specific patient population.[55]

Guidelines for Meeting Nutritional Goals. In 1997, the European Society for Clinical Nutrition and Metabolism created guidelines for meeting nutritional goals in patients with end-stage liver disease.[53]They recommend initiation of enteral feeding when oral intake is inadequate. In patients with compensated cirrhosis, the guidelines recommend that patients consume 25-35 kcal/kg body weight per day of nonprotein energy and 1-1.2 g/kg body weight per day of protein or amino acids. In patients with complicated cirrhosis associated with malnutrition, nonprotein energy should be increased to 35-40 kcal/kg body weight per day and protein intake should increase to 1.5 g/kg body weight per day. According to the guidelines, protein intake should decrease to 0.5-1.5 g/kg body weight/day if stage I or II encephalopathy is present, and to 0.5 g/kg body weight/day if stage III or IV encephalopathy is present. More recent evidence suggests that protein restriction should not be recommended, even in the setting of episodic hepatic encephalopathy.[56]

The distribution of calorie intake throughout the day has also been studied. It has been proposed that eating a late evening snack could alleviate the shift towards lipid oxidation by reducing the length of time a patient fasts overnight. Indeed, a late evening meal has been shown to improve the nitrogen balance[57] and raise the nonprotein respiratory quotient.[58] A typical recommendation for patients with advanced liver disease is to consume four to five small meals per day, as well as a late evening snack.

Supplementation with branched-chain amino acids.The usefulness of branched-chain amino acid (BCAA) supplementation in patients with cirrhosis has long been debated. It was proposed that depletion of BCAAs, as seen in many patients with advanced liver disease, might promote the development of hepatic encephalopathy by enhancing the passage of aromatic amino acids across the blood-brain barrier, resulting in the synthesis of false neurotransmitters. For this reason, it was hypothesized that BCAA supplementation might improve hepatic encephalopathy. Early investigations, therefore, focused on BCAAs as a potential treatment for hepatic encephalopathy. Although some controlled trials showed no benefit of BCAAs with respect to mental function,[59] several trials showed a significant improvement in hepatic encephalopathy with BCAA treatment.[60, 61] A 2003 review of 11 randomized trials concluded that BCAAs improve hepatic encephalopathy, particularly when administered enterally to patients with chronic encephalopathy.[62]

Although there are conflicting data, there is more evidence of the beneficial effects of BCAAs to support their use in the treatment of malnutrition in patients with advanced cirrhosis. Marchesini et al. performed a multicenter, randomized trial examining the role of oral BCAA supplementation in patients with advanced liver disease.[63] The trial consisted of 174 patients with advanced cirrhosis who received 1 year of nutritional supplementation with BCAAs, lactoalbumin, or maltodextrins. BCAA administration was advantageous with regard to rates of mortality, progression of liver failure, and hospital admission. The most significant limitation that the investigators found was poor compliance with the BCAA-enriched diet; in the BCAA group, 15% of patients did not complete the treatment course. Poor compliance was attributed to poor palatability of the BCAA supplement. A recent multicenter, randomized, nutrient-intake-controlled trial demonstrated that oral supplementation with BCAAs for 2 years improved survival, serum albumin concentration, and quality of life in patients with decompensated cirrhosis.[64]

Recent studies advocate the use of nocturnal BCAA administration.[65] It is believed that BCAAs that are consumed during the day are primarily used as a source of energy for physical exercise, whereas when administered at night, BCAAs might be preferentially used for protein synthesis.

Correcting Nutrient Deficiencies. Nutritional therapy in patients with chronic liver disease should not only focus on treatment of PCM, but should also aim to correct specific nutrient deficiencies. Patients with advanced liver disease commonly develop micronutrient deficiencies. For example, patients with alcoholic liver disease who continue to consume alcohol are particularly at risk for deficiency of thiamine, folate, and magnesium.[66] Most patients with advanced liver disease, but particularly those with cholestatic liver disease, develop a deficiency of fat-soluble vitamins.[67]

Decreased serum vitamin A levels result from fat malabsorption, as well as defective mobilization of vitamin A from the liver.[68] One of the common complications of vitamin A deficiency is night blindness, which has been shown to improve with vitamin A supplementation, generally at a dose of 25,000 units/day for 4-12 weeks.[69] Persistent problems with dark adaptation, despite adequate supplementation, might result from concomitant zinc deficiency.[70] Vitamin A deficiency typically resolves within 2 weeks of liver transplantation.[69] Vitamin A toxicity is a potential risk of vitamin A supplementation. Vitamin A toxicity typically causes elevated transaminase levels and can eventually lead to cirrhosis, chronic hepatitis, or portal hypertension.[70] Although it was traditionally thought that the development of vitamin A toxicity requires doses well in excess of the recommended range, data now suggest that cirrhosis can develop at therapeutic doses of vitamin A (e.g. 25,000 IU/day for 6 years).[71] Liver disease resulting from vitamin A toxicity can persist for up to 1 year after discontinuation of the supplement.

Vitamin D deficiency is another complication of chronic liver disease, resulting primarily from malabsorption; decreased UV light exposure and inadequate dietary intake might also be contributing factors to vitamin D deficiency. Impaired hepatic 25-hydroxylation of vitamin D is also seen in patients with alcoholic cirrhosis.[72] Calcium deficiency, and eventually osteomalacia or osteoporosis, results from decreased intestinal calcium absorption. Up to 43% of patients undergoing transplant evaluation have osteoporosis.[73] There are conflicting data on whether vitamin D supplementation improves osteoporosis in patients with advanced liver disease. It has been suggested that osteoporosis does not respond to vitamin D supplementation in patients with primary biliary cirrhosis,[62] but it can improve in patients with alcoholic liver disease when 25-hydroxyvitamin D supplementation (25-50 mg/day) is taken.[74] A proposed guideline is to supplement all patients who have chronic liver disease with calcium (1 g/day) and vitamin D3 (800 IU/day).[75, 76]

Zinc deficiency commonly occurs in patients with cirrhosis and has been implicated in the pathogenesis of hepatic encephalopathy.[77] Zinc supplementation at doses of 600 mg/day for 3 months has been shown to improve mental functioning in patients with hepatic encephalopathy,[78] although other studies show conflicting findings, and the role of zinc in treating hepatic encephalopathy remains controversial.

Conclusion

Malnutrition is a well-known complication of advanced liver disease and is associated with detrimental consequences if left untreated. It is, therefore, of critical importance to assess the nutritional status of all patients with chronic liver disease and to optimize nutritional support in these patients. Treatment should focus on maintaining adequate protein and caloric intake and correcting nutrient deficiencies. Strategies include the consumption of frequent small meals and a late evening snack to reduce protein breakdown. When oral intake is insufficient, early implementation of enteral feeding should be considered. The use of BCAAs remains controversial, but the most recent data promote their therapeutic potential. Malnutrition is a potentially reversible condition that, when identified and treated appropriately, can lead to improved outcomes.