The Aetiology And Consequences Of Liver Diseases
Liver diseases may have a number of causes:
- Infectious agents
- Metabolic or nutritional factors
- Biliary obstruction
The pathologic changes in the liver's parenchymal cells are similar regardless of the aetiology of the disease. Basic changes include their atrophy, fatty infiltration, fibrosis, and necrosis.
Symptoms And Their Origins
- Wasting, loss of subcutaneous tissue, and peripheral muscle wasting indicate that the body's stores of fat and protein are being used to meet requirements for energy. This may be found in patients with advanced hepatocellular and cholestatic diseases.
- The pallor of the skin and conjunctivae may indicate anemia. Deficiencies of iron, vitamin B12, and folic acid are common causes of anemia in liver disease.
- Glossitis and cheilosis may be found in a variety of vitamin-deficient states - in relation to vitamin B12 and folic acid, as mentioned previously as well as riboflavin and nicotinic acid.
- Vitamin A deficiency may lead to poor vision in the dark; this may be made worse by zinc deficiency Both deficiencies may occur in patients with liver diseases.
- The gums may bleed as a result of vitamin C deficiency.
- Diffuse bone pain may reflect metabolic bone disease. Poor absorption of the fat-soluble vitamin D may be exacerbated by the reduced bioavailability of dietary calcium. (Decreased fat absorption leads to an increase of free fatty acids in the lumen of the gut, these fatty acids bind calcium, which is then excreted in the stool.
- Ascites and peripheral edema may result from hypoalbuminemia a condition that arises owing to the decreased synthesis of albumin in the liver and inadequate protein intake.
- Ecchymoses, epistaxis, and other signs of bleeding diathesis may result from hypoprothrombinemia caused by malabsorption of vitamin K or the inadequate dietary intake of the vitamin.
- Asterixis, confusion, somnolence, and coma are all evidence of protein intolerance. Hepatic encephalopathy or coma is a serious complication of advanced liver disease; it is associated with changes in consciousness, behavior, and neurological status. The three proposed general mechanisms that may lead to hepatic coms are:
- An accumulation of toxin due to impaired hepatic function, ammonia being the leading candidate.
- An altered plasma amino-acid composition (a decreased ratio of branched chain to aromatic amino acids).
- An increase in serum and brain neuroinhibitory substances (an increase in gamma-aminobutyric acid).
- Muscle tremors may result from hypomagnesemia Patients with liver disease are at risk of magnesium depletion as a result of poor dietary intake, diuretic therapy, or diarrhea.
- Jaundice is a symptom common to many diseases of the liver and biliary tract and consists of a yellow coloring of the skin and body tissues due to the accumulation of bile pigments in the blood.
- Obstructive jaundice is caused by the interference of the flow of the bile by a stone, tumors, or an inflammation of the ducts' mucosa.
- Hemolytic jaundice is caused by abnormally large destruction of blood cells such as occurs in yellow fever, pernicious anemia, etc.
- Toxic jaundice is caused by poisons, drugs, and various infections.
Laboratory tests and guides for the diagnosis of liver and biliary diseases
Liver function tests are frequently required for the assessment of patients with jaundice, and they are also used in the investigation of suspected liver disease in many other clinical situations. When considering the results of these tests it is important to remember that the results of some of them (e.g. serum albumin. serum alkaline phosphatase, serum glutamic oxaloacetic transaminase) may be abnormal in the absence of liver disease: it is important to interpret the results of these tests of liver functions in the light of other information available concerning the patient.
Nutritional considerations for liver disease
For sufferers of liver disease, a diet is recommended that provides generous amounts (80-90 g daily) of protein of high nutritional value for the repair of tissue and the prevention of any fatty infiltration and degeneration of liver cells. A high carbohydrate intake (250-300 g) is suggested to maintain an adequate reserve of glycogen.
Although there is no evidence that liver disease is influenced by fat, fat and fatty foods are poorly tolerated by the body as their absorption from the intestine is impaired owing to the lack of bile salt. Therefore a low-fat diet (30-50g per day) is recommended.
To compensate for deficiencies of vitamins, a generous amount of vitamin B complex must be provided. If edema and ascites are present a restriction to 2g sodium per day is suggested.
Which food items are classified as containing first-class protein?
- Meat, poultry, fish, egg, milk, and milk products contain first-class protein.
Name some foods which are good sources of the vitamin B complex.
- Fresh green vegetables and fruits are good sources of the vitamin B complex.