Chapter 15 The Liver The liver lies in the upper right quadrant of the abdominal cavity and is the largest organ in the body. The functions of the liver are diverse and essential. When the liver is damaged, all body systems are affected. Tests of Liver Function - Measurement of total bilirubin. - Measurement of liver enzymes, including serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), and alkaline phosphatase. Levels increase with liver disease. -

Measurement of plasma protein concentration. Levels decrease with liver disease. - Measurement of prothrombin time (a test of coagulation).It increases with liver disease. - Ultrasound, computed tomography (CT) scan, and magnetic resonance imaging (MRI) can indicate structural defects or stones in the bile duct or gallbladder. - Liver biopsy allows tissues to be observed directly for confirmation of infection, fatty infiltration or fibrosis, and cancer.

Pathophysiologic Concepts 1-Portal Hypertension Portal hypertension is excessively high pressure in the portal vein. Normal portal venous pressure is approximately 3 mmHg. Pressure greater then 9 to 10 mmHg in the portal vein is considered portal hypertension. Portal hypertension develops when the resistance to blood flow through or out of the liver is high. Excessive blood flow going into the liver can also lead to portal hypertension which lead to:

a-Portal-Systemic Venous Shunts: collateral vessels, or shunts, open between the portal vein and the systemic veins that drain the abdominal wall, esophagus, and rectum. The shunts divert blood flow, bypassing the liver. b-Splenomegaly:blood flow is diverted to the spleen via the splenic vein leading to its enlargement

2-Jaundice Jaundice is the yellowish discoloration of the skin and sclera of the eyes seen as a result of excess bilirubin in the blood (greater than 1.2 mg/dL). Bilirubin is a product of red blood cell breakdown. Jaundice is also referred to as icterus. There are three main types of jaundice: hemolytic jaundice, intrahepatic jaundice, and extrahepatic obstructive jaundice. 3-Cirrhosis Diffuse liver scarring and fibrosis characterize cirrhosis. Normal liver architecture and function are disrupted. Causes include infections such as hepatitis and bile duct obstruction. Alcohol is the toxin most often implicated in causing injury and inflammation in the liver

Conditions of Disease or Injury 1- Physiologic Jaundice This condition is especially prevalent in premature infants. It occurs as a result of increased breakdown of fetal hemoglobin in the first few days after birth combined with the immaturity of the liver at birth. 2- Hemolytic Disease of the Newborn This disease may result from either ABO or Rh incompatibility between the infant and the mother.

3-Viral Hepatitis a-Hepatitis A Hepatitis A (HAV) was formerly called infectious hepatitis. It is primarily passed by oral-fecal contamination resulting from poor hygiene or contaminated food. b-Hepatitis B Hepatitis B (HBV) is sometimes called serum hepatitis. It is a serious disease throughout the world, with over 300 million people suffering from chronic infection. c-Hepatitis C Hepatitis C (HCV) was identified in This RNA virus is passed in the same manner as HBV Hepatitis D Hepatitis E

Clinical manifestations can range from asymptomatic to profound illness, hepatic failure, and death. There are three stages of illness for all types of hepatitis: the prodromal stage, the icterus (jaundice) stage, and the convalescent (recovery) period. 1 - The prodromal stage, called the preicterus period characterized by: - General malaise - Fatigue - Symptoms of upper respiratory tract infection - Myalgia (muscle pain) - An aversion to most foods

2- The icterus or jaundice stage is the second stage of viral hepatitis, and it may last 2 to 3 weeks or much longer. It is characterized in most people, as its name suggests, by the development of jaundice. Other manifestations include: - Worsening of all symptoms present during the prodromal stage - Hepatic tenderness and enlargement - Splenomegaly - Possible itchiness (pruritus) of the skin

3-The recovery stage is the third stage of viral hepatitis and usually happens within 4 months for HBV and HCV and within 2 to 3 months for HAV. During this period: - Symptoms subside, including jaundice. - Appetite returns. Diagnostic Tools - Liver enzymes are abnormal. - Antibodies to the virus are elevated.

4- Liver Failure Liver failure is the ultimate outcome of any severe liver disease. Liver failure may follow years of low- grade HCV infection or may occur suddenly with the onset of fulminating HBV. 5- Liver Cancer It is usually seen in individuals who have a history of HBV or HCV infection or who have chronic liver disease, for example, cirrhosis. Clinical Manifestations - Dull abdominal pain. - A feeling of abdominal fullness.

- Nausea and vomiting. - Jaundice. - Anorexia (decreased appetite). - Hepatomegaly - If the tumor obstructs the bile duct, ascites may develop. Diagnostic Tools - Elevated liver enzymes. - Elevated levels of a protein normally not present in adult serum, alpha-fetoprotein. Treatment - Surgery for some tumors is possible. - Chemotherapy.