Procedure Practice 06/15/98 - Coding Recommendations

Feature Article 06/15/98:

The Liver 

Diseases - Neoplasms - Diagnostic and Therapeutic Procedures
    

Structure and Function

The liver is the largest organ in the body. It weighs about 3 pounds and is roughly the size of a football. Its vascularity is responsible for its dark color. The liver has four sections called lobes. The right lobe is the largest, followed by the left lobe. Two smaller lobes, the caudate and the quadrate, are located on the posterior inferior surface of the right lobe. Located on the right side of the abdominal cavity, just above the duodenum, the liver is attached to the anterior abdominal wall by ligaments. The liver is a highly complex organ that performs hundreds of functions.
  

Circulation

Oxygenated blood from the lungs is pumped to all body tissues and then returned to the heart and lungs for reoxygenation and release of carbon dioxide. This is called systemic circulation. Blood from the bowel and spleen flow to and through the liver before returning to the heart. This is called portal circulation, and the large vein through which blood is brought to the liver is called the portal vein. After passing through the liver, blood flows into the hepatic vein, which leads into the inferior vena cava to the right side of the heart. The liver also receives some blood directly from the heart via the hepatic artery. In the esophagus, stomach, small intestine, and rectum, the portal circulation and veins of the systemic circulation are connected. Under normal conditions, little to no back flow from portal circulation into systemic circulation occurs.
   

Bilirubin Secretion

The liver is the site of bile formation. Bile contains bile salts, fatty acids, cholesterol, bilirubin, and other compounds. The components of bile are synthesized and modified in hepatocytes (the predominant cell type in the liver) and secreted into small bile ducts within the liver itself. These small bile ducts form a branching network of progressively larger ducts that ultimately become the common bile. Bile flows from the common bile duct to the small intestine. Bilirubin is a yellow pigment that derives primarily from old red blood cells. It is taken up by hepatocytes from the blood, modified in the hepatocytes to a water soluble form, and secreted into the bile.
  

Biochemical Functions

The liver performs many biochemical functions. Blood clotting factors are synthesized in the liver. Albumin, the major protein in the blood, is also synthesized in and secreted from the liver. The modification and/or synthesis of bile components also takes place in the liver. Many of the body's metabolic functions occur primarily in the liver including the metabolism of cholesterol and the conversion of proteins and fats into glucose. The liver is also where most drugs and toxins, including alcohol, are metabolized.

Other key functions performed by the liver include: storage of vitamins, minerals, and sugars; regulation of fat stores transport; maintenance of proper levels of many chemicals and drugs in the blood; maintenance of hormone balance; principle production site of blood in the fetus; regeneration of its own damaged tissue; storage of iron; and production of immune factor.

Diseases

Viral Hepatitis

Five viruses are known to cause liver disease: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). However, recent evidence suggests the existence of additional hepatitis viruses. HAV and HEV, which are spread through contaminated food and water, do not cause chronic liver disease. In contrast, the bloodborne hepatitis viruses, HBV, HCV and HDV may lead to persistent infection and chronic hepatitis. These viruses, similar to the AIDS virus, are major public health problems throughout the world. Unlike hepatitis, HIV has received enormous attention in the lay and scientific communities, although hepatitis viruses affect many more individuals both in the U.S. and worldwide. While hepatitis virus infections may not appear as deadly as HIV, they still can have lethal consequences many years after acute infection.

• Hepatitis A virus (HAV) causes the most prevalent type of hepatitis. It is a highly contagious virus transmitted through the fecal-oral route, through close person-to-person contact, or by ingesting contaminated food or water. It is the seventh most commonly reported infectious disease in the United States and accounts for as many as 65 percent of all viral hepatitis cases in the U.S. each year. Common symptoms of HAV are fatigue, nausea and vomiting, fever, chills, jaundice, right upper quadrant pain, light-colored feces, and dark urine. Two vaccines provide long-term protection and eliminate the need for repeated shots. These vaccines typically are administered as a single initial shot followed by a booster shot in about six to 18 months.

• Hepatitis B virus (HBV) is transmitted via blood and body fluid contact. IV drug users, individuals with multiple sex partners, and infants of infected women are at high risk for the disease. HBV infection causes acute illness with loss of appetite, fatigue, arthralgias and myalgias, abdominal pain, and jaundice. It can also cause chronic illness that leads to liver damage (cirrhosis), liver cancer, and death. An estimated 1.25 million people in the United States have chronic HBV infection, and 4,000 to 5,000 people die each year from hepatitis B. Factors predisposing to chronic HBV include infection in the neonatal period, a subclinical (sometimes undiagnosed) acute infection, and infection in the presence of immunologic compromise in the host. The most important determinant is age: risk of developing chronic HBV varies inversely with the age of onset of infection. Chronic infection occurs in 90% of infants infected at birth. Among those infected, 5% to 10% become carriers. A strong relationship exists between persistent HBV infection and hepatocellular carcinoma. Chronic infections resulting from maternal- neonatal transmission present the greatest risk of HCC. Routine HBV screening is now performed on all pregnant women with prompt postnatal treatment of infants born to infected mothers.
      
  The hepatitis B vaccine prevents both acute HBV infection and chronic hepatitis B disease. Available since 1982, hepatitis B vaccines currently administered in the United States are made using recombinant DNA technology and contain only a portion of the outer protein of HBV. The vaccine does not contain any live components and is given as a series of three intramuscular doses.

• Hepatitis C virus (HCV) is the most significant cause of chronic liver disease and the number one reason for liver transplantation in the United States. Hepatitis C has traditionally been associated with blood transfusions, but studies show that it is more likely to spread through sexual contact or through occupational exposure among health care workers. Unlike hepatitis A and B infections, which have clearly identifiable active disease states, hepatitis C seldom has an identifiable acute phase of infection. HCV is associated with the majority of instances of chronic hepatitis and liver disease.
     
  Interferons are the only agents thus far proven to be effective in the treatment of chronic hepatitis. Development of an HCV vaccine has been slow for several reasons: 1) the virus was not identified until 1996; 2) stable cultures of the virus are difficult to establish; and 3) the HCV mutates at a very high rate.

• Hepatitis D virus (HDV) is an incomplete virus and cannot thrive on its own. In humans, HDV infection only occurs in the presence of hepatitis B infection. HDV is transmitted by blood and blood products. The risk factors for infection are similar to those for HBV infection. HDV infection can be acquired either as a coinfection with acute HBV or as a superinfection of persons with chronic HBV infection.

• Hepatitis E virus (HEV) is seldom seen in the United States; however, it is a major cause of viral hepatitis in developing countries. This virus, like HAV, is transmitted via the fecal-oral route. There is no vaccine to prevent or treat the disease. Purification of drinking water sources is the primary focus of prevention efforts.
     

Chronic Hepatitis

Chronic hepatitis is ongoing injury to liver cells with inflammation continuing for more than six months. Hepatitis B and C account for more than 75% of chronic hepatitis cases worldwide. In the U.S., approximately 1.2 million people have chronic hepatitis B, and 3.9 million people have chronic hepatitis C. Chronic hepatitis can be mild and limited or extensive with destruction of liver cells. A liver biopsy confirms the diagnosis, aids in establishing etiology, and reveals the severity of inflammation, fibrosis or cirrhosis.

Individuals with chronic hepatitis generally have mild symptoms, but over a period of years cirrhosis may appear. Liver transplantation is an accepted form of therapy when chronic hepatitis becomes life threatening, usually as a result of complications of cirrhosis.
   

Autoimmune Hepatitis

Autoimmune hepatitis is a progressive inflammation of the liver that primarily affects young women. The exact etiology of this disease is unknown, but it is associated with abnormalities of the immune system. Blood tests identify antinuclear antibodies (ANA) or smooth muscle antibodies (SMA) and increased gamma globulin in the blood of most patients. Some patients have other autoimmune disorders such as thyroiditis, ulcerative colitis, diabetes mellitus, vitiligo, or Sjogren's syndrome. Patients may also have complications such as ascites (abdominal fluid) or hepatic encephalopathy (mental confusion). Immunosuppression with prednisone or a combination of prednisone and azathioprine is the standard treatment for autoimmune hepatitis.
   

Alcohol-Related Disorders

Alcohol stresses the liver by, among other things, disorganizing cellular lipids and altering the liver cells' ability to deal with other. Three separate liver disorders are related to alcohol: fatty liver (steatosis), alcoholic hepatitis, and alcoholic cirrhosis.

• Fatty liver, the most common alcohol-related liver disorder, is the accumulation of fat in liver cells. Fatty liver causes hepatomegaly and right upper quadrant abdominal discomfort. Severe fatty liver may cause temporary jaundice and abnormalities of liver function. Abstinence from alcohol can completely reverse the condition without leaving residual cirrhosis.

• Alcoholic hepatitis is an acute illness characterized by nausea, vomiting, right upper and middle abdominal pain, fever, jaundice, enlarged and tender liver, and an elevation of the white blood cell count. Sometimes alcoholic hepatitis may be present without symptoms.

• Alcoholic cirrhosis is a degenerative disease in which liver cells are damaged and replaced by scar formation (fibrosis). As fibrosis accumulates, blood flow through the liver is diminished, causing even more liver cells to die. Cirrhosis occurs in 10% to 15% of people who consume large amounts of alcohol over a prolonged period of time.
     

Other Disorders

• Non-Alcoholic Steatohepatitis (NASH) is a condition characterized by inflammation of the liver and increased intrahepatic fat deposits. These patients are often diabetics and/or overweight, but they do not drink alcohol. NASH may progress to cirrhosis. The exact cause of the disease is not known; however, researchers believe that immune factors play a role.

• Primary Biliary Cirrhosis (PBC) is a chronic, non-alcohol related liver disease that causes slow, progressive destruction of bile ducts in the liver. Continued liver inflammation causes scarring and eventually leads to cirrhosis. Women are affected 10 times more frequently than men, with onset of disease between the ages of 30-60. Symptoms include jaundice, cholesterol deposits in the skin, fluid accumulation and darkening of the skin. Arthritis, thyroid problems, and osteomalacia (softening of bone tissue) may also be present. The disease is not inherited, but it is more common among siblings and in families where one member has previously been diagnosed. Treatment consists of a restricted diet, vitamin supplementation, and medical control of symptoms such as itching. When medical treatment is no longer effective, transplantation is indicated.
     

• Primary Sclerosing Cholangitis is a disease in which the bile ducts inside and outside the liver become narrowed due to inflammation and scarring. This causes bile to accumulate in the liver and can result in damage to liver cells. Although the exact cause of primary sclerosing cholangitis is unknown, genetic and immunologic factors appear to play a role. It may occur alone, but approximately 70% of patients have associated inflammatory bowel disease, particularly ulcerative colitis. Treatment focuses on medical management of symptoms and surgical techniques to open major blockages of the common bile duct.
     
• Type-1 Glycogen Storage Disease a deficiency of the enzyme glucose -6- phosphatase which maintains normal blood glucose during fasting. Patients with this particular disorder suffer from growth failure and hepatomegaly. Abnormal blood chemistry reveals low blood sugar concentration and elevated levels of lipids and uric acid. A surgical procedure called a portacaval shunt may be performed to bypass the blood around the liver.

• Hemochromatosis is a common inherited disorder that causes the body to absorb and store too much iron. A bronze discoloration of the skin may be the only clue that hemochromatosis is present. Liver damage can progress to cirrhosis if the illness is not treated. Damage to other organs may cause arthritis, heart problems, impotence, and chronic fatigue. Blood tests for serum iron and either total iron binding capacity (TIBC) or transferrin are good screening devices. Once the diagnosis is confirmed, one to two pints of blood are removed each week until iron stores decrease to a normal level. It may take from several months to several years to remove all excess iron. After the iron stores are reduced to normal, the therapy is generally continued every 2 to 4 months for life to prevent re-accumulation of iron.
     

Pediatric Disorders

• Alagille syndrome is an inherited disorder of infants and young children, the disease is characterized by a progressive loss of bile ducts within the liver over the first year of life and narrowing of bile ducts outside the liver. Bile builds up in the liver causing damage to liver cells. Treatment focuses on efforts to increase the flow of bile from the liver, maintain normal growth and development, and prevent or correct any of the specific nutritional deficiencies that often develop.

• Primary Biliary Atresia afflicts approximately 1:12,000 infants. It is a bile duct disorder of uncertain etiology in which rapid and progressive scarring leads to obstruction of the flow of bile between the liver and the intestine (the extrahepatic bile duct system). Eventually, even the ducts within the liver become obliterated. Surgical creation of an opening between the liver and intestine (Kasai procedure) improves bile flow somewhat; however, in most children the ducts within the liver continue to deteriorate. More infants and children require liver transplantation for biliary atresia than for any other single liver disease.

• Chronic Active Hepatitis slowly destroys and replaces the normal liver cells with scar tissue through a process which resembles an allergy to the child's own liver tissue. Treatment centers around effort to maintain liver functions until transplant is available.

• Galactosemia is an inherited disease in which lactase, the enzyme needed to digest lactose (milk sugar) is missing, causing lactose to build up in the liver and other organs. This condition causes cirrhosis, cataracts, and brain damage. In order to survive, infants must be fed an artificial formula without lactose.

• Reye's Syndrome is an acute disorder in which fat accumulates in the liver. Reye's syndrome is a rare complication of common childhood respiratory infections, flu, and chickenpox. Children who are not diagnosed early may lapse into a coma and die. Early signs of Reye's syndrome are persistent vomiting, listlessness, staring, and drowsiness. Because aspirin may contribute to the problem of Reye's syndrome, doctors advise against the use of aspirin-containing medications in chickenpox and during outbreaks of influenza-like disease.

• Wilson's Disease is a rare inherited disorder in which excessive amounts of copper accumulate in the body. The copper then builds up in the liver, brain and other organs. Treatment for Wilson's disease is long-term therapy with a chelating agent (zinc, D-penicillamine, or trientine) to rid the body of the excess copper.

Neoplasms

Cavernous Hemangiomas

These are the most common benign liver tumors and are often found by chance on an X-ray imaging study of the liver. Unless they are extremely large, a specific therapy is usually not required. Because this tumor may enlarge in women taking hormone pills, physicians often recommend discontinuing birth control pills or hormone drug therapy after menopause.
  

Hepatocellular Adenoma and Focal Nodular Hyperplasia

These are the other common benign tumors of the liver. Both of these tumors are also usually found by chance although hepatocellular adenoma has a substantial risk of bleeding within the tumor and into the peritoneal (abdominal) cavity. The use of X-ray imaging tests, hepatic arteriography, or biopsy may be required to make the diagnosis of this tumor. Hepatocellular adenomas are quite sensitive to hormonal therapy and may become smaller when birth control pills or hormones are stopped.
   

Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma frequently arises in people already ill with advanced liver disease. This malignant disease is often multifocal and incurable at presentation. Among cirrhotic patients, 20 percent will develop HCC over five years. Hepatic resection is generally only offered to patients with solitary tumors less than five cm in diameter. For patients with single small tumors that are nonresectable (for instance, located near the portal vein) liver transplantation is the only surgical option.

Diagnostic and Therapeutic Procedures

The ABC of LFTs

Liver function tests (LFTs) are blood tests that assess the general state of the liver and biliary system. Routine blood tests can be divided into those tests that are true LFTs, such as serum albumin or prothrombin time, and those tests that are simply markers of liver or biliary tract disease, such as the various liver enzymes. In addition to the usual liver tests obtained on routine automated chemistry panels, physicians may order more specific liver tests such as viral serologic tests or autoimmune tests that can determine the specific cause of a liver disease.

Liver enzymes are grouped into two general categories. The first group includes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). These enzymes are indicators of liver cell damage. The other frequently used liver enzymes are alkaline phosphatase and gamma-glutamyltranspeptidase (GGT and GGTP) that indicate obstruction in the biliary system either within the liver or in the larger bile ducts outside the liver. ALT and AST are enzymes produced in the liver cells. These enzymes leak out into general circulation when liver cells are injured. ALT is a more specific indicator of liver inflammation since the AST may also be elevated in the presence of heart or other muscle damage. In acute liver injury such as acute viral hepatitis, the ALT and AST may be elevated to the high 100s or over 1,000 U/L. In chronic hepatitis or cirrhosis, the elevation of these enzymes may be minimal (less than 2-3 times normal) or moderate (100-300 U/L). Mild or moderate elevations of ALT or AST are nonspecific and may be caused by a wide range of liver diseases. ALT and AST are often used to monitor the course of chronic hepatitis and the response to treatments while alkaline phosphatase and GGT are elevated in a large number of disorders that affect the drainage of bile.

Bilirubin is the main bile pigment in humans which, when elevated, causes the yellow discoloration of the skin and eyes called jaundice. Bilirubin is formed primarily from the breakdown of a substance in red blood cells called heme. It is taken up from blood, processed through the liver, and then secreted into the bile by the liver. Normal individuals have only a small amount of bilirubin circulating in blood (less than 1.2 mg/dL). Conditions that cause increased formation of bilirubin or decreased removal from the blood stream may result in elevated serum bilirubin.

Other commonly used indicators of liver function are the serum albumin and prothrombin time. Albumin is a major protein formed by the liver. Chronic liver disease causes a decrease in the amount of albumin produced and lower levels of serum albumin. The prothrombin time, which is also called protime or PT, is a test to assess blood clotting. Blood clotting proteins are made by the liver. If the liver is significantly injured these proteins are not normally produced. Prothrombin time is usually expressed in seconds and compared to a normal control patient's blood.

In addition, special tests may be used to make a precise diagnosis of the cause of liver disease. Elevations in serum iron, the percent of iron saturated in blood, or the storage protein ferritin may indicate the presence of hemochromatosis. Low serum ceruloplasmin and the presence of copper in urine indicate Wilson's disease. A positive antimitochondrial antibody indicates the underlying condition of primary biliary cirrhosis. Striking elevations of serum globulin, another protein in the blood, and the presence of antinuclear antibodies (ANA) or antismooth muscle antibodies are clues to the diagnosis of autoimmune chronic hepatitis. Finally, specific blood tests that allow the precise diagnosis of hepatitis A, hepatitis B, hepatitis C, and hepatitis D.

In summary, blood tests are used to diagnose or monitor liver disease. They may be simply markers of disease (e.g., ALT, AST, alkaline phosphatase, and GGT), more true indicators of overall liver function (serum bilirubin, serum albumin, and prothrombin time), or specific tests that allow the diagnosis of an underlying cause of liver disease.
   

Transhepatic Venous Sampling

In this diagnostic procedure, a catheter is inserted through the jugular vein into the subclavian, then through the superior and inferior vena and finally into the hepatic vein. From this site, blood is sampled for a variety of substances. Levels of gastrin, insulin, and glucagon can be assessed to diagnose gastric and pancreatic tumors. The presence of hepatic markers aids assessment of liver metastases from other primary tumor sites. Venous wedge pressures can be taken at this site to monitor portal blood pressures.
  

Biopsies

Liver tissue for disease diagnosis can be obtained in several ways. The most common liver biopsy method is percutaneous needle insertion into the liver. A variation of this technique uses radiographic imaging to guide the needle into the liver. This approach is used when localized tumors are identified by ultrasound or computed tomography (CT).

Other commonly used biopsy techniques are laparoscopy, transvenous or transjugular liver biopsy, and surgical liver biopsy. With laparoscopy, a lighted laparoscope is inserted through a small incision in the abdominal wall. The internal organs are moved away from the abdominal wall by carbon dioxide gas insufflated into the abdomen. Instruments are then passed through the scope or through separate puncture sites to obtain tissue samples from several different areas of the liver. Transvenous or transjugular liver biopsy may be performed by a radiologist in special circumstances, e.g., on patients with coagulopathy or ascites. In this procedure, a catheter is inserted into the internal jugular vein in the neck and radiologically guided into the hepatic vein that drains the liver. A small biopsy needle is then inserted through the catheter into the liver to obtain a tissue sample. Finally, a liver biopsy may be done during an open abdominal operation, enabling the surgeon to inspect the liver and take one or more biopsy samples as needed.
  

Peritoneo-Venous Shunt

This device returns ascitic fluid from the peritoneal cavity to systemic circulation. Two commonly used devices are the LeVeen and Denver shunts. A perforated tube is placed in the peritoneal cavity and connected to the internal jugular vein in the neck by a tube passed through the subcutaneous tissues. This way, the ascitic fluid is drained from the abdominal cavity back into systemic circulation. An implanted valve prevents fluid from flowing back into the peritoneal cavity.
  

Transjugular Intrahepatic Portosystemic Shunt (TIPPS)

This procedure involves the creation of a tissue tract from the low pressure venous system that drains the liver to the high pressure venous system that feeds the liver. The tract is made by inserting a catheter through the jugular vein and guiding to the hepatic vein. Under radiologic guidance, the surgeon makes an artificial tract to directly drain the portal vein into the general circulation. This is done via the use of several inflatable balloons followed by insertion of an expandable wire mesh stent. TIPSS procedures are performed on patients with serious complications of cirrhosis, i.e., hemorrhagic gastroesophageal varices or abdominal ascites.
  

Portacaval Shunt

This procedure is another method to reroute blood around a hypertensive portal circulatory system. The surgeon performs a side-to-side connection between the portal vein and the inferior vena cava.
  

Percutaneous Ultrasound-guided Ethanol Injection (PEI)

In this procedure, a hepatic neoplasm is injected with ethanol via passage of a needle through the abdominal skin and subcutaneous tissue directly into the tumor mass. Ultrasound imaging guides the needle and targets the tumor. This procedure is an inexpensive and effective treatment for small tumors in patients who are not healthy enough for more invasive surgery.
  

Transcatheter Oily Chemoembolization; Transcatheter Arterial Chemoembolization (TOCE/TACE)

In this procedure, lipiodol (a form of poppy seed oil that concentrates in malignant cells) is coupled with a chemotherapeutic agent such as adriamycin. Under local anesthesia, a catheter is advanced from the groin into the hepatic artery branches that flow through the liver. A mixture containing collagen particles and chemotherapy is injected through the catheter. The procedure combines the selective delivery of a chemotherapeutic drug directly into the tumor mass with collagen blockage of the blood supply. In enables the interventional radiologist to deliver much higher, more effective concentrations of the drug than can be done with standard intravenous chemotherapy, while leaving healthy liver tissue intact.
  

Kasai Procedure

This procedure is an open abdominal surgery in which the small intestine, usually the jejunum, is connected to an intrahepatic biliary duct. A healthy (patent) intrahepatic duct is divided and sutured in end-to-side fashion to an opening made in the small intestine. The procedure enables the flow of bile into the digestive tract. It is performed on patients with severely dysfunctional or fibrotic extrahepatic bile ducts, for example, infants with primary biliary atresia.
  

Liver Transplants

The most common type of liver transplant is an orthoptic liver transplant. This procedure involves harvesting the new liver from a cadaver, removal of the recipient's liver, and implantation of the donor liver into the recipient. Newer transplantation techniques include reduced size or cutdown transplants and split liver transplants in which only a portion of a liver is transplanted. Out of these techniques evolved the living-related liver transplantation program. Participants in this transplant program are primarily children who receive the left lateral lobe of a sibling or parent.

Practice Makes Perfect!

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Read the operative reports on our procedure practice page. Then assign ICD-9-CM diagnosis and ICD-9-CM and CPT-4 procedure codes. Compare your answers with our coding recommendations. Good luck!

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Structure and Function - Diseases - Neoplasms - Diagnostic and Therapeutic Procedures
     

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