Liver The largest glandular organ in the body Weight: 1.5 kg Reddish brown and has four unequal lobes Supplying vessels: 1. hepatic and portal vein Location: right upper quadrant, below the diaphragm the only internal human organ capable of natural regeneration of lost tissue
Functions: Gluconeogenesis the synthesis of glucose from certain amino acids, lactate or glycerol Glycogenolysis the breakdown of glycogen into glucose Glycogenesis the formation of glycogen from glucose Protein metabolism Lipid metabolism: Cholesterol synthesis Lipogenesis, the production of triglycerides (fats).
The liver produces coagulation factors . The liver produces and excretes bile The liver also produces insulin-like growth factor 1 (IGF-1), a polypeptide protein hormone that plays an important role in childhood growth and continues to have anabolic effects in adults. The liver is a major site of thrombopoietinproduction,a glycoprotein hormone that regulates the production of platelets by the bone marrow.
The breakdown of insulin and other hormones The liver breaks down hemoglobin, creating metabolites that are added to bile as pigment (bilirubin and biliverdin). The liver breaks down or modifies toxic substances , methylation and most medicinal products in a process called drug metabolism. This sometimes results in toxication, when the metabolite is more toxic than its precursor. The liver converts ammonia to urea.
The liver stores a multitude of substances, including glucose The liver is responsible for immunological effects- the reticuloendothelial system of the liver contains many immunologically active cells, acting as a 'sieve' for antigens carried to it via the portal system. The liver produces albumin, the major osmolar component of blood serum The liver synthesizes angiotensinogen a hormone that is responsible for raising the blood pressure when activated by renin, an enzyme that is released when the kidney senses low blood pressure.
Liver functions include liver enzymes, are groups of clinical biochemistry laboratory blood assays designed to give information about the state of a patient's liver.
Albumin is a protein made specifically by the liver, and can be measured cheaply and easily. It is the main constituent of total protein; the remaining fraction is called globulin . The half-life of albumin is approximately 20 days. Albumin is not considered to be an especially useful marker of liver synthetic function; coagulation factors
Alaninetransaminase (ALT), also called Serum GlutamicPyruvateTransaminase (SGPT) or Alanineaminotransferase (ALT) is an enzyme present in hepatocytes (liver cells). Aspartatetransaminase (AST) Aspartatetransaminase (AST) also called Serum GlutamicOxaloaceticTransaminase (SGOT) or aspartateaminotransferase (ASAT) is similar to ALT in that it is another enzyme associated with liver parenchymal cells.
Alkaline phosphatase (ALP) Alkaline phosphatase (ALP) is an enzyme in the cells lining the biliary ducts of the liver. ALP levels in plasma will rise with large bile duct obstruction, intrahepaticcholestasis or infiltrative diseases of the liver.
Bilirubin is a breakdown product of heme, a part of hemoglobin in red blood cells. The liver is responsible for clearing the blood of bilirubin. Bilirubin is taken up into hepatocytes conjugated to make it water-soluble, and secreted into the bile, which is excreted into the intestine.
Coagulation test The liver is responsible for the production of coagulation factors. The international normalized ratio (INR) measures the speed of a particular pathway of coagulation, comparing it to normal. If the INR is increased, it means it is taking longer than usual for blood to clot. The INR will only be increased if the liver is so damaged that synthesis of vitamin K-dependent coagulation factors has been impaired: it is not a sensitive measure of liver function.
Hepatitis inflammation of the liver characterized by the presence of inflammatory cells in the tissue of the organ can be self-limiting, healing on its own, or can progress to scarring of the liver. is is acute when it lasts less than six months and chronic when it persists longer.
Causes of acute hepatitis Viral hepatitis: Hepatitis A through E (more than 95% of viral cause), Herpes simplex, Cytomegalovirus, Epstein-Barr, yellow fever virus adenoviruses. Non viral infection: toxoplasma, Leptospira, Q fever,rocky mountain spotted fever Alcohol Toxins: Amaniia toxin in mushrooms, carbon tetrachloride, asafetida Drugs: Paracetamol, amoxycillin, antituberculosis medicines, minocycline and many others Ischemic hepatitis (circulatory insufficiency) Pregnancy Auto immune conditions, e.g., Systemic Lupus Erythematosus (SLE) Metabolic diseases, e.g., Wilson's disease
symptoms flu-like symptoms, common to almost all acute viral infections and may include malaise, muscle and joint aches, fever, nausea or vomiting, diarrhea, and headache. More specific symptoms, which can be present in acute hepatitis from any cause, are: profound loss of appetite, aversion to smoking among smokers, dark urine, yellowing of the eyes and skin and abdominal discomfort.
Jaundice can be a late feature and may indicate extensive damage. Other features include abdominal fullness from enlarged liver or spleen, low grade fever and fluid retention Extensive damage and scarring of liver leads to weight loss, easy bruising and bleeding tendencies. Acne, abnormal menstruation, lung scarring, inflammation of the thyroid gland and kidneys may be present in women with autoimmune hepatitis
Causes of chronic hepatitis Viral hepatitis: Hepatitis B with or without hepatitis D, hepatitis C causes chronic hepatitis Autoimmune: Autoimmune hepatitis Alcohol Drugs: methyldopa, nitrofurantoin, isoniazid, ketoconazole Non-alcoholic steatohepatitis Heredity: Wilson's disease, alpha 1-antitrypsin deficiency Primary biliary cirrhosis and primary sclerosingcholangitis occasionally mimic chronic hepatitis
Stages of Chronic hepatitis Pre-icteric stage- with early symptoms that are non-specific, flu-like symptoms, that include malaise, fatigue, headache, myalgia, anorexia, nausea and vomiting and diarrhea Icteric- occurs a few days to weeks after the icteric stage and include jaundice, dark colored urine, light colored stools and steatorrhea Post-icteric stage- a convalescent stage lasting a few weeks jaundice resolves and appetite returns
Hepatitis A Accounts for 20-25% of cases of clinical hepatitis in the world Formerly called infectious hepatitis Caused by an RNA virus Mode of transmission: oral-fecal, sexually Incubation period:15-50 days, average of 30 days Confers immunity against itself
Symptoms Asymptomatic, mostly Flu-like upper respiratory symptom Low grade fever Anorexia, indigestion Jaundice and dark urine
Diagnosis Large liver and spleen HAV antibodies in the serum Hepatitis A antigen in the stool
Prevention Proper hygiene Vaccine (Havrix and Vagta) Administration of globulin
Management Bed rest Small frequent feedings
Hepatitis B Can be found in blood, saliva, semen and vaginal secretions Can be transmitted by blood, through mucous membranes and breaks in the skin and the placenta Develops into a more chronic type or within 6 months
Symptoms Resembles hepatitis A but has a longer incubation period Symptoms are insidious and variable Loss of appetite, dyspepsia Generalized aching, malaise, weakness Enlarged liver and spleen Jaundice Diagnosis: prsence of HBsAg and antibodies
Treatment and Prevention Interrupt chain of transmission Active and passive immunization Antiviral agents Bed rest Adequate nutrition
Hepatitis C Formerly referred to as non-A, non-B hepatitis Mode of transmission: blood and body fluids Incubation period: 15-160 days Symptoms appear milder than HBV
Hepatitis D Occurs in some cases of hepatitis B because the virus requires the hepatitis B surface antigen for its replication Mode of transmission: blood and body fluids Symptoms and treatment are almost the same with hepatitis B