Liver Cirrhosis - Research Paper Example

?Running head: LIVER CIRRHOSIS Liver Cirrhosis Insert Insert Affiliation Here Liver is the most important organ of the human body, and performs a number of vital functions such as metabolism and detoxification. This paper discusses the anatomy and physiology of the liver, apart from elaborating liver cirrhosis, a serious disorder of the liver that results from formation of scar tissue and damage of hepatocytes. Cirrhosis of the liver leads to failure in the performance of its usual functions, thereby having a cascade effect on the health of other organs. Symptoms range from mild signs such as nausea and swelling, to severe complications such as jaundice and gallstones. A number of direct factors such as chronic alcoholism, viral hepatitis and genetic diseases, and indirect factors such as bile duct obstruction cause cirrhosis. Diagnosis of the disease is based on physical and medical examinations, apart from liver biopsy and CT scans. Treatment mainly aims at delaying disease progression, as the disease is irreversible and impossible to eliminate. Keywords: Liver, cirrhosis, hepatocytes, bile, duct, edema, ascitis Liver Cirrhosis Of all the organs that constitute the human body, perhaps there is none other that compares with the liver in the extent of multitasking and hard work it does. This paper summarizes the anatomy and physiology of the liver, and also attempts at describing liver cirrhosis, a debilitating liver disease. The causes, tests and treatments of liver cirrhosis are also discussed. The Liver Weighing about 1.4 kg, i.e. about 3 lb in adults, the liver is the heaviest organ of the human body. It is also the second largest organ, skin being the first. It is located below the rib cage at the right hand side of the body. To be precise, it occupies part of the epigastric regions in the abdomino-pelvic cavity and part of the hypochondriac region (Tortora and Derrickson, 2008, p. 945). A healthy liver is an extremely important asset for an individual’s health and well-being. As Chopra (2001) writes, the liver is “akin to a master conductor who is orchestrating a number of essential functions”, working as a “central manufacturing factory”, a processing plant for toxic waste and even as a warehouse, all at the same time (p. 4). Anatomy of the Liver The liver has two irregularly sized lobes – the larger right lobe, and the smaller left lobe. The two lobes are separated by a fold of mesentery, forming the smooth falciform ligament (Tortora and Derrickson, 2008, p. 945). The right lobe is five to six times bigger than the left lobe. The liver has a smooth texture and is a vascular organ rich in blood vessels that impart it a reddish brown color. It has an intricate and interconnected network of liver cells called hepatocytes, along with large amounts of ducts and veins (Chopra, 2001, p. 4). The hepatocytes, which are the principal liver cells, constitute almost 70% of the entire mass of the liver and are derived from the embryonic endoderm (Zorn, 2008, para. 3). Although some anatomists believe that the right lobe has an inferior quadrate lobe and a posterior caudate lobe, studies based on internal morphology and the distribution of blood vessels reveal that these two lobes more appropriately belong to the left lobe (Tortora and Derrickson, 2008, p. 945). The smooth falciform ligament that divides the two lobes of the liver extends from below the diaphragm, thereby helping the liver to stay suspended in the abdominal cavity. A round ligament, called the ligamentum teres, which is a remnant of the fetal umbilical vein, is present in the free border of the falciform ligament and extends from the liver to the umbilicus. A pear-shaped sac called the gall bladder is located in a depression that is present on the posterior surface of the liver. It hangs from the anterior-inferior margin of the liver and measures 7-10 cm. An analysis of liver histology reveals that it consists of bile canaliculi and hepatic sinusoids, apart from hepatocytes. The hepatocytes (liver cells) are specialized and functional epithelial cells that perform a variety of secretory and metabolic functions. They are arranged in three dimensional aggregates called hepatic laminae. Bile canaliculi are ducts that collect the bile produced by hepatocytes and transport it to bile ductules. The hepatic sinusoids are permeated blood capillaries that receive oxygenated blood from the hepatic artery. (Tortora and Derrickson, 2008, p. 945). All these together constitute the functional anatomy of the liver. Physiology of the Liver The liver performs essential metabolic, endocrine as well exocrine functions (Zorn, 2008, para. 2). The liver produces albumin, which is a major protein in blood and is involved in regulating the body’s fluid balance (Chopra, 2001, p. 7). The blood’s essential clotting factors are also produced in the liver. The gall bladder, present in the liver, stores and secretes bile produced by the liver. Bile consists of bile salts and bilirubin, and is essential for the emulsification and breakdown of fats in the intestines. Bilirubin is a pigment that is released by red blood cells when they die. This pigment is broken down by the liver and is released in bile. The liver also breaks down ammonia, a by-product of digestion, into urea which is then excreted. The liver also performs other important metabolic functions like the breakdown of cholesterol and fats into simpler substances. The liver maintains the body’s blood sugar concentrations within a narrow range. Moreover, sugars such as fructose are transformed into glucose by the liver. The liver also stores excess glucose in the form of glycogen. The liver is also a storehouse of iron. Another significant function of the liver is detoxification. Kupffer cells present in the liver filter blood and remove bacteria and foreign bodies. The liver also breaks down alcohol into acetaldehyde. It also eliminates other toxins from the blood. In addition, most drugs are metabolized in the liver. Liver Cirrhosis Liver cirrhosis is a disorder characterized by scarring of the liver and formation of scar tissue, resulting from an injury or a chronic disease (“Cirrhosis”, n.d.). Formation of scar tissue inhibits the liver from performing its routine and vital functions such as detoxification, production of bile for digestion, storage of energy, etc. The formation of scar tissue also interrupts blood flow through the organ and deforms its structure (AGA institute, 2007). About 5% of the people diagnosed with cirrhosis tend to get liver cancer, and about 25,000 people die each year in the US alone, from complications of cirrhosis, half of which are associated with chronic alcoholism (“Cirrhosis”, n.d.; AGA institute, 2007). Hepatitis is another leading cause of cirrhosis. If left untreated, it results in liver failure, ultimately leading to death. Liver cirrhosis is characterized by symptoms such as spider-like blood vessels, abdominal pain, weight loss, and nausea, loss of appetite, severe itching and tiredness. Complications associated with cirrhosis include jaundice, easy bruising, bleeding and nosebleeds, gallstones, edema (painful swelling of the legs due to fluid buildup), ascites (swelling of the abdomen), mental confusion, portal hypertension (high blood pressure in the vein supplying the liver), kidney failure, over-sensitivity to drugs and medications, enlarged veins in stomach and esophagus, menstrual abnormalities, and impotence (American Liver Foundation, 2011; AGA institute, 2007). Gallstones and jaundice are usually observed at the late or advanced stages of liver cirrhosis. Jaundice occurs due to buildup of bile pigment in the body instead of being passed on to the gallbladder. Deposition of bile products in the skin results in its yellowing and also causes intense itching. Gallstones result when there is not enough bile reaching the gall bladder. Due to loss of liver function, there is a buildup of excess ammonia in blood, resulting in toxicity and loss of mental function, along with sleep disturbances and coma. This condition is termed as hepatic encephalopathy. Loss of liver function also affects drug metabolism. As liver cirrhosis renders it incapable of removing drugs and medicines from the blood effectively, they persist in blood longer than required, thereby inducing severe side effects and drug sensitivity. Portal hypertension that results from blockage of normal blood flow to the liver leads to enlargement of the spleen, further complicating the disease condition (AGA institute, 2007). Causes of Liver Cirrhosis? The causes of liver cirrhosis may be direct or indirect. Direct causes include chronic liver diseases such as hepatitis that cause injury to liver cells, and indirect causes include bile duct damage, inflammation, or obstruction. Direct causes: Chronic alcoholism: It is probably the most common cause of cirrhosis and leads to swelling of the liver and loss of liver function. Chronic viral hepatitis and autoimmune hepatitis: Chronic liver diseases such as hepatitis C, and rarely hepatitis B and D, which result from viral attack, are the second major causes of cirrhosis. Nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver disease (NAFLD): This leads to inflammation of the liver, in addition to fat buildup. Obesity, diabetes, coronary artery disease and high blood cholesterol are often associated with this condition. Indirect causes: Genetic diseases: Hereditary diseases, such as Wilson’s disease, which is caused when too much copper is stored in the liver, brain and kidneys, Hemochromatosis, which results when excess iron is stored in the liver and other organs, often result in liver cirrhosis. Other inheritable diseases include Alpha-1 antitrypsin deficiency, glycogen storage diseases, cystic fibrosis and galactosemia. Diseases of the bile duct: These include primary biliary cirrhosis, primary sclerosing cholangitis and biliary atresia. Primary biliary cirrhosis results when the bile ducts are destroyed. Primary sclerosing cholangitis results when the bile ducts inside and outside the liver are inflamed or scarred. Biliary atresia results due to injury of the bile ducts that drain bile from the liver. Diseases of the bile ducts obstruct the flow of bile from liver to small intestines, leading to swelling of the liver. This eventually results in cirrhosis. Diagnosis of Liver Cirrhosis Liver cirrhosis is often diagnosed based on laboratory tests, medical history and symptoms, CT scans, ultrasounds, physical examinations and liver biopsies. Very rarely, laparoscopy is also used for diagnosis. Antimitochondrial antibody and antimitochondrial M2 antibody test (AMA), smooth muscle antibodies test (SMA), antinuclear antibodies test (ANA), and bilirubin tests are used for diagnosing primary biliary cirrhosis (American Association for Clinical Chemistry, 2011). Treatment of Liver Cirrhosis The scar tissue formed in liver cirrhosis is difficult to eliminate, but can be prevented from further aggravation. In case of severe and irreparable damage, a liver transplant is often the last resort. Since cirrhosis is irreversible, treatment modalities are focused on delaying or stopping disease progression, rather than reversing the formation of scar tissue. Lifestyle changes such as discontinuation of alcohol consumption, physical activity for reduction of obesity etc. are aimed at delaying further formation of scars. In case of hepatitis, antiviral medications are prescribed for prevention of further liver damage. Good nutrition that includes easily metabolizable proteins such as those in fish, poultry and legumes, and incorporation of a low-sodium diet is vital (AGA institute, 2007). Use of diets rich in branched-chain amino acids in conjunction with lactulose and non-absorptive antibiotics have also been suggested (Okita, Watanabe, and Nagashima, 1985; Masami, Kazumi, and Yoshihide, 1999). Medications are prescribed for controlling symptoms such as itching. Diuretics and low-sodium diets are recommended for easy elimination of fluids for the prevention of symptoms such as edema and ascites. Alternative medications such as the use of Silymarin, which is extracted from seeds of milk thistle and has a protective effect on the liver, are recommended for the treatment of both, cirrhosis and hepatitis (NCCAM, 2011). Several interventional treatments are used for relieving portal hypertension and bile duct obstruction. TIPS (transjugular intrahepatic portosystemic shunt), a procedure used for creating a tunnel in the liver to relieve blockage in blood flow that is the source of portal hypertension, significantly reduces many other symptoms associated with liver cirrhosis (SIR, 2011). A similar procedure is used for relieving bile duct obstruction that is an indirect cause of cirrhosis. Cirrhosis is a seriously debilitating and irreversible disease afflicting liver, the most important organ of the human body. Its prevention by modulation of lifestyle habits and avoidance of risk factors such as chronic alcoholism are thus important for the protection of this vital organ. Future studies on potential treatments that reverse rather than delay the progression of this disease are thus warranted. References AGA Institute. (2007). Understanding the cirrhosis of the liver. The American Gastroenterological Association. Retrieved 2011, September 10, from http://www.gastro.org/patient-center/brochure_cirrhosis.pdf American Association for Clinical Chemistry. (2011). In Lab tests online. Retrieved 2011, September 10, from http://labtestsonline.org/understanding/analytes/ama/tab/test American Liver Foundation. (2011). In liverfoundation.org. Retrieved 2011, September 10, from http://www.liverfoundation.org/abouttheliver/info/cirrhosis/ Chopra, S. (2001). The Liver Book: A Comprehensive Guide to Diagnosis, Treatment, and Recovery. New York, NY: Simon and Schuster. “Cirrhosis”. (n.d.). In MedlinePlus. Retrieved 2011, September 10, from http://www.nlm.nih.gov/medlineplus/cirrhosis.html Masami, I., Kazumi, I. and Yoshihide, F. (1999). Treatment of liver cirrhosis. Medicine and Drug Journal, 35, 1116-1119. Retrieved 2011, September 10, from http://sciencelinks.jp/j-east/article/199914/000019991499A0438058.php NCCAM. (2011). Milk thistle. National Center for Complementary and Alternative Medicine, National Institutes of Health, USA. Retrieved 2011, September 10, from http://nccam.nih.gov/health/milkthistle/ataglance.htm Okita, M., Watanabe, A. and Nagashima, H. (1985). Nutritional treatment of liver cirrhosis by branched-chain amino acid-enriched nutrient mixture. Journal of Nutritional Science and Vitaminology, 31, 291-303. Retrieved 2011, September 10, from http://www.ncbi.nlm.nih.gov/pubmed/4067664/ SIR. (2011). Interventional Treatments for Liver Disease. Society of Interventional Radiology, Virginia, USA. Retrieved 2011, September 10, from http://www.sirweb.org/patients/liver-disease/ Tortora, G.J. and Derrickson, B. (2008). Principles of Anatomy and Physiology. n.a: John Wiley and Sons. Retrieved 2011, September 10, from http://books.google.com/ Zorn, A.M. (2008). Liver Development. In StemBook. Retrieved 2011, September 10, from http://www.stembook.org/node/512 Read More