steatosis

Steatosis, Simple Fatty Liver, Nonalcoholic fatty liver disease (NAFLD) & Nonalcoholic Steatohepatitis (NASH)

Introduction

Classification of Non-Alcoholic Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) describes a range of conditions involving the liver that affect people who drink little or no alcohol.

I. Simple Fatty Liver (Steatosis): The mildest type - It consists on an accumulation of fat within your liver that usually causes no liver damage.

The buildup of fat in the cells of the liver is called fatty liver or Steatosis, and in itself is not harmful. Many people have fatty liver.

Early on, the buildup of fat does not affect the function of the liver and you will have no symptoms. As fat continues to build up and inflammation occurs, liver function begins to decline and symptoms develop. This inflammation leads to scarring and severe damage of the liver. There is no clear reason why some people with fatty liver develop NASH and others do not.

II. Non-Alcoholic Steatohepatitis (NASH): A potentially more serious type - It is associated with liver-damaging inflammation and sometimes the formation of fibrous tissue. In some cases, this can progress either to cirrhosis, which can produce progressive, irreversible liver scarring, or to liver cancer.

In NASH, the fat buildup causes inflammation of the liver which can lead to symptoms such as fatigue, weight loss and weakness.

NASH typically appears in people during middle-age, in their 40s and 50s, but it can happen earlier or later in life. It occurs equally in men and women.

NASH progresses to advanced liver disease in about 15% to 20% of cases.

Once the liver has been damaged, there is a much greater chance that the damage will continue and get worse. In some cases, the disease progression can stop and even reverse on its own without treatment. In other cases, however, NASH can slowly get worse and cause scarring (fibrosis) of the liver, which leads to cirrhosis. Cirrhosis means that the liver has become scarred and hardened and is not able to function normally.

Nonalcoholic fatty liver disease affects all age groups, including children. Most often, it's diagnosed in middle-aged people who are overweight or obese, and who may also have diabetes and elevated cholesterol and triglyceride levels.

With the increasing incidence of obesity and diabetes in Western countries, nonalcoholic fatty liver disease has become a growing problem. Although its true prevalence is unknown, some estimates suggest it may affect as many as one-third of American adults.

Because early-stage nonalcoholic fatty liver disease rarely causes any symptoms, it's often detected because of abnormal results of liver tests done for unrelated issues. Treatments for nonalcoholic fatty liver disease include weight loss, exercise, improved diabetes control and the use of cholesterol-lowering medications.

Causes

*Note: PIC - A fatty liver is enlarged and has a greasy, pale yellow look.

It's unclear exactly what causes nonalcoholic fatty liver disease. But many researchers believe that metabolic syndrome - a cluster of disorders that increase the risk of diabetes, heart disease and stroke - likely plays an important role in its development. Signs and symptoms of metabolic syndrome include:

Obesity, particularly around the waist (abdominal obesity)

High blood pressure (Hypertension)

One or more abnormal cholesterol levels - high levels of triglycerides, a type of blood fat, or low levels of high-density lipoprotein (HDL) cholesterol, the "good" cholesterol

Resistance to insulin, a hormone that helps to regulate the amount of sugar in your blood

Of these, insulin resistance may be the most important trigger of simple fatty liver (steatosis) and nonalcoholic steatohepatitis (NASH). Because both conditions can remain stable for many years, causing little harm, researchers have proposed that a "second hit" to the liver may trigger a progression to cirrhosis. Possible triggers include bacterial infections, hormonal abnormalities or an accumulation of excess iron in the liver caused by hemochromatosis.

It's also unclear exactly how a liver becomes fatty. The fat may come from other parts of your body, or your liver may absorb an increased amount of fat from your intestine. Another possible explanation is that your liver loses its ability to change fat into a form that can be eliminated. But one thing's certain: The eating of fatty foods, by itself, doesn't produce a fatty liver.

Researchers suspect that there may be a genetic component to the disorder, and are investigating whether genes play a role in the development of nonalcoholic fatty liver disease or if genes may affect the severity of the disorder.

Risk factors

Although the cause of nonalcoholic fatty liver disease is unclear, the condition is associated with many risk factors. The three most important ones are closely related to metabolic syndrome and insulin resistance:

Overweight and obesity. Your risk increases with every pound of excess weight. More than 70 percent of people with nonalcoholic steatohepatitis (NASH) are obese. Overweight is defined as having a body mass index between 25 and 29.9; obesity is defined as having a body mass index of 30 or higher.

Diabetes. When your body becomes resistant to the effects of insulin or your pancreas doesn't produce enough insulin to maintain a normal blood sugar (glucose) level, this can damage many organs in your body, including your liver . As many as three in four people with NASH also have diabetes.

Hyperlipidemia. High cholesterol levels and elevated triglycerides are common in people who develop NASH. It's estimated that up to 80 percent of people with NASH have hyperlipidemia.

Other risk factors include:

Abdominal surgery. Operations to remove large sections of the small intestine (small bowel resection), treat obesity (gastric bypass) or bypass parts of the small intestine (jejunal bypass) often lead to rapid weight loss, which may increase your risk of nonalcoholic fatty liver disease.

Medications. These include oral corticosteroids (prednisone, hydrocortisone, others), synthetic estrogens (Premarin, Ortho-Est, others) for menopause, amiodarone (Cordarone, Pacerone) for heart arrhythmias, tamoxifen for breast cancer and methotrexate Rheumatrex, Trexall), an immune-suppressing medication for rheumatoid arthritis.

Other conditions. These include Wilson's disease, a hereditary condition that affects copper levels; Weber-Christian disease, which affects nutrient absorption; and abetalipoproteinemia, a rare congenital disorder that affects the ability to digest fat. Inherited metabolic disorders that increase the risk of cirrhosis include galactosemia, a rare disorder that affects the way the body metabolizes milk sugar (lactose), and glycogen storage diseases, which prevent glycogen, the stored form of glucose, from being formed or released when your body requires it.

Prevention

Your best defense against nonalcoholic fatty liver disease is to maintain a healthy weight and normal cholesterol and blood sugar levels. This strategy, along with avoiding excess alcohol and other substances that could be harmful to your liver, can help reduce your risk of liver disease.

Signs and symptoms

You may not have signs and symptoms of simple fatty liver (steatosis) or nonalcoholic steatohepatitis (NASH). When symptoms do occur, they are usually vague and nonspecific and may include:

Fatigue

Malaise

A dull ache in your upper right abdomen, a possible sign of an enlarged liver

At a more advanced stage, such as cirrhosis, non-alcoholic fatty liver disease may cause:

Lack of appetite

Weight loss

Nausea

Small, red spider veins under your skin or easy bruising

Weakness

Fatigue

Jaundice: Yellowing of your skin and eyes and dark, cola-colored urine

Bleeding from engorged veins in your esophagus or intestines

Loss of interest in sex

Fluid in your abdominal cavity (Ascites)

Itching on your hands and feet and eventually on your entire body

Swelling of your legs and feet from retained fluid (Edema)

Mental confusion, such as forgetfulness or trouble concentrating (Encephalopathy)

Liver failure

When to seek medical advice

If you're experiencing any of the symptoms of nonalcoholic fatty liver disease - fatigue, malaise and a dull ache in your upper right abdomen - see your doctor. Make an appointment for a screening if you have risk factors for nonalcoholic fatty liver disease such as obesity, diabetes and hyperlipidemia.

Screening and diagnosis

*PIC - The slide on the left shows fat accumulation in liver cells. The slide on the right shows healthy liver cells.

Because early-stage nonalcoholic fatty liver disease seldom causes signs and symptoms, your doctor may discover it during a routine medical examination. Many cases are detected after doctors order liver tests to monitor people taking cholesterol-lowering drugs.

Before diagnosing nonalcoholic fatty liver disease, your doctor may order blood tests for other conditions that cause liver damage, such as hepatitis B and C. He or she will also inquire about your current and past alcohol consumption. Excess alcohol consumption - three or more drinks a day for men and two or more drinks a day for women - can also cause fatty liver and steatohepatitis.

If your doctor suspects nonalcoholic fatty liver disease, you're likely to have certain tests, including:

Liver Function Test: A damaged liver releases certain enzymes. If this blood test shows that these enzymes are mildly elevated, it may be a sign that you have liver damage.

Scintigraphy: A diagnostic test in which a two-dimensional picture of a body radiation source is obtained through the use of radioisotopes. For example, scintigraphy of the biliary is done to diagnose obstruction of the bile ducts by a gallstone, a tumor, or another problem; disease of the gallbladder; and bile leaks. For cholescintigraphy, a radioactive chemical is injected intravenously into the patient. The chemical is removed from the blood by the liver and secreted into the bile that the liver makes. The chemical then goes everywhere that the bile goes: into the bile ducts, the gallbladder, and the intestine. By placing over the abdomen a camera that senses radioactivity, a picture of the gallbladder; and bile leaks. For cholescintigraphy, a radioactive chemical is injected intravenously into the patient. The chemical is removed from the blood by the livercan be obtained that corresponds to where the radioactivity is within the bile-filled liver, ducts, and gallbladder. Other scintigraphic tests are done similarly.

Ultrasound (Ultrasonography): This noninvasive test uses sound waves to produce a picture of internal organs, including your liver. Abdominal ultrasound is painless and usually takes less than 30 minutes. While you lie on a bed or examining table, a technician applies a conductive gel to your abdomen and places a hand-held device (transducer) on the area, moving the transducer along your skin to locate your liver and adjacent organs. The transducer emits sound waves that are reflected from your liver and transformed into a computer-generated image.

Computerized Tomography (CT): This test uses X-rays to produce cross-sectional images of your body.

Magnetic Resonance Imaging (MRI): Instead of X-rays, MRI creates images using a magnetic field and radio waves. Sometimes a contrast dye may be used. The test can take from 15 minutes to an hour. You may find an MRI scan to be more uncomfortable than a CT scan. That's because you'll likely be reclining on a stretcher enclosed in a tube with very little space above you or beside you. The thumping noise the machine generates also is disturbing to some people.

Liver Biopsy: Although other tests can provide a great deal of information about the extent and type of liver damage, a biopsy is the only way to definitively diagnose nonalcoholic fatty liver disease. Your doctor may perform this procedure if you are over age 45 and you are obese or have diabetes. Additionally, your doctor is more likely to order this test if your liver function tests don't go back to normal after treatment. In this procedure, a small sample of tissue is removed from your liver and examined under a microscope. Your doctor is likely to use a thin cutting needle to obtain the sample. Needle biopsies are relatively simple procedures requiring only local anesthesia, but your doctor may choose not to do one if you have bleeding problems or severe abdominal swelling (ascites). Risks include bruising, bleeding and infection.

Treatment

The best treatment for you depends on the underlying cause of your nonalcoholic fatty liver disease. Preferred treatments include:

Weight loss and exercise. If your body mass index is above 25, a diet and exercise program may reduce the amount of accumulated fat in your liver. The most effective diet is rich in fiber and low in calories and saturated fat, with total fat accounting for no more than 30 percent of total calories. But go slowly. Aim to lose 10 percent of your body weight over six months, because rapid weight loss may lead to a worsening of liver disease. Even if you aren't overweight or obese, a healthy diet and daily physical activity may reduce inflammation, lower elevated levels of liver enzymes and decrease insulin resistance.

Diabetes control. Strict management of diabetes with diet, medications or insulin lowers blood sugar, which may prevent further liver damage. It may also reduce the amount of accumulated fat in your liver.

Cholesterol control. Controlling elevated levels of cholesterol and triglycerides with diet, exercise and cholesterol-lowering medications may help stabilize or reverse nonalcoholic fatty liver disease.

Avoidance of toxic substances. If you have nonalcoholic fatty liver disease - especially nonalcoholic steatohepatitis (NASH) - don't drink alcohol. Also avoid medications and other substances that can cause liver damage. Talk to your doctor about which drugs to avoid.

Under investigation
There's no standard medical treatment specifically for nonalcoholic fatty liver disease. Several possible treatments are under investigation, but so far none has proved effective. These approaches include:

Vitamins E and C. Since both vitamins are antioxidants, it's thought that they may reduce liver damage caused by oxidants, unstable oxygen molecules that damage cell membranes.

Ursodiol (Actigall). Most commonly used to treat gallstones, this drug decreases production of bile acids, which may in theory help lower elevated levels of liver enzymes in people with liver disease.

Other medications. Researchers are studying the effects of several medications on insulin resistance and nonalcoholic fatty liver disease in people with and without diabetes. These include metformin (Glucophage, Glucophage XR), pioglitazone (Actos), rosiglitazone (Avandia) and betaine (Cystadane). Another drug being investigated is orlistat (Xenical), a medication that blocks the absorption of some of the fat from your food. Early results indicate that orlistat may reduce the amount of fat in the liver.

Bariatric surgery. While abdominal weight-loss surgery coupled with rapid weight loss has been implicated as contributing to the development of NASH, some research suggests that bariatric surgery combined with modest weight loss may reduce the inflammation and scarring associated with NASH.

Complementary and Alternative medicine

A number of complementary and alternative therapies - many of them herbs and nutritional supplements - purport to improve liver heath. Among these are milk thistle, alpha-lipoic acid (thioctic acid), vitamin E, N-acetyl cysteine (an amino acid byproduct) and omega-3 fatty acids.

Because many vitamins and dietary supplements, such as vitamin A, iron, valerian and comfrey, have the potential to worsen liver problems, be sure to check with your doctor before taking any vitamin, herb or dietary supplement.

Complications

It's difficult to predict the course of nonalcoholic fatty liver disease in any one person. Most people with simple fatty liver (steatosis) or nonalcoholic steatohepatitis (NASH) don't develop serious liver problems. Without treatment, however, these conditions can lead to cirrhosis and liver failure in some people. This risk is highest in people older than 45 who are affected by obesity, diabetes or both. Some estimates suggest that as many as one in four people with nonalcoholic fatty liver disease may develop serious liver disease within 10 years. In some cases, a liver transplant may be the only option.

LIVER BLOOD ENZIMES - LIVER FUNCTION TEST

Introduction

An initial step in detecting liver damage is a simple blood test to determine the presence of certain liver enzymes in the blood. Under normal circumstances, these enzymes reside within the cells of the liver. But when the liver is injured, these enzymes are spilled into the blood stream.

Among the most sensitive and widely used of these liver enzymes are the aminotransferases. They include aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). These enzymes are normally contained within liver cells. If the liver is injured, the liver cells spill the enzymes into blood, raising the enzyme levels in the blood and signaling the liver damage.

What are the aminotransferases?

The aminotransferases catalyze chemical reactions in the cells in which an amino group is transferred from a donor molecule to a recipient molecule. Hence, the names "aminotransferases".

Medical terms can sometimes be confusing, as is the case with these enzymes. Another name for aminotransferase is transaminase. The enzyme aspartate aminotransferase (AST) is also known as serum glutamic oxaloacetic transaminase (SGOT); and alanine aminotransferase (ALT) is also known as serum glutamic pyruvic transaminase (SGPT). To put matters briefly, AST = SGOT and ALT = SGPT.

Normally, where are the aminotransferases?

AST (SGOT) is normally found in a diversity of tissues including liver, heart, muscle, kidney, and brain. It is released into serum when any one of these tissues is damaged. For example, its level in serum rises with heart attacks and with muscle disorders. It is therefore not a highly specific indicator of liver injury.

ALT (SGPT) is, by contrast, normally found largely in the liver. This is not to say that it is exclusively located in liver but that is where it is most concentrated. It is released into the bloodstream as the result of liver injury. It therefore serves as a fairly specific indicator of liver status.

What are normal levels of AST and ALT?

The normal range of values for AST (SGOT) is from 5 to 40 units per liter of serum (the liquid part of the blood).

The normal range of values for ALT (SGPT) is from 7 to 56 units per liter of serum.

What do elevated AST and ALT mean?

AST (SGOT) and ALT (SGPT) are sensitive indicators of liver damage from different types of disease. But it must be emphasized that higher-than-normal levels of these liver enzymes should not be automatically equated with liver disease. They may mean liver problems or they may not. The interpretation of elevated AST and ALT levels depends upon the whole clinical picture and so it is best done by doctors experienced in evaluating liver disease.

The precise levels of these enzymes do not correlate well with the extent of liver damage or the prognosis (outlook). Thus, the exact levels of AST (SGOT) and ALT (SGPT) cannot be used to determine the degree of liver disease or predict the future. For example, patients with acute viral hepatitis A may develop very high AST and ALT levels (sometimes in the thousands of units/liter range). But most patients with acute viral hepatitis A recover fully without residual liver disease. For a contrasting example, patients with chronic hepatitis C infection typically have only a little elevation in their AST and ALT levels. Some of these patients may have quietly developed chronic liver disease such as chronic hepatitis and cirrhosis (advanced scarring of the liver).

What liver diseases cause abnormal aminotransferase levels?

The highest levels of AST and ALT are found with disorders that cause the death of numerous liver cells (extensive hepatic necrosis). This occurs in such conditions as acute viral hepatitis A or B, pronounced liver damage inflicted by toxins as from an overdose of acetaminophen (brand-name Tylenol), and prolonged collapse of the circulatory system (shock) when the liver is deprived of fresh blood bringing oxygen and nutrients. AST and ALT serum levels in these situations can range anywhere from ten times the upper limits of normal to thousands of units/liter.

Mild to moderate elevations of the liver enzymes are commonplace. They are often unexpectedly encountered on routine blood screening tests in otherwise healthy individuals. The AST and ALT levels in such cases are usually between twice the upper limits of normal and several hundred units/liter.

The most common cause of mild to moderate elevations of these liver enzymes is fatty liver. In the United States, the most frequent cause of fatty liver is alcohol abuse. Other causes of fatty liver include diabetes mellitus and obesity. Chronic hepatitis C is also becoming an important cause of mild to moderate liver enzyme elevations.

What medications cause abnormal aminotransferase levels?

A host of medications can cause abnormal liver enzymes levels. Examples include:

Pain relief medications such as aspirin, acetaminophen (Tylenol), ibuprofen (Advil, Motrin), neproxen (Narosyn), diclofenac (Voltaren) and phenybutazone (Butazolidine)

Anti-seizure medications such as phenytoin (Dilantin), valproic acid, carbamazepine (Tegretol), and phenobarbital

Antibiotics such as the tetracyclines, sulfonamides, isoniazid (INH), sulfamethoxazole, trimethoprim, nitrofurantoin, etc.

Cholesterol lowering drugs such as the "statins" (Mevacor, Pravachol, Lipitor, etc.) and niacin

Cardiovascular drugs such as amiodarone (Cordarone), hydralazine, quinidine, etc.

Anti-depressant drugs of the tricyclic type

With drug-induced liver enzyme abnormalities, the enzymes usually normalize weeks to months after stopping the medications.

What are less common causes of abnormal aminotransferase levels?

Less common causes of abnormal liver enzymes in the United States include chronic hepatitis B, hemachromatosis, Wilson's disease, alpha-1-antitrypsin deficiency, celiac sprue, Crohn's disease, ulcerative colitis, and autoimmune hepatitis. Though not as common as hepatitis C, hepatitis B can cause chronic liver disease with persistently abnormal liver enzymes.

Hemachromatosis is a genetic (inherited) disorder in which there is excessive absorption of dietary iron leading to accumulation of iron in the liver with resultant inflammation and scarring of the liver.

Wilson's disease is an inherited disorder with excessive accumulation of copper in diverse tissues including the liver and the brain. Copper in liver can lead to chronic liver inflammation, while copper in brain can cause psychiatric and motor disturbances.

Alpha-1-antitrypsin deficiency is an inherited disorder in which the lack of a glycoprotein (carbohydrate-protein complex) called alpha-1-antitrypsin lead to chronic lung disease (emphysema) and to liver disease.

Autoimmune hepatitis results from liver injury brought about by the body's own antibodies and defense systems attacking the liver.

Celiac sprue is a small intestinal illness where a patient has allergy to gluten and develops gas, bloating, diarrhea, and in advanced cases malnutrition. Patietns with celiac sprue can also develop mildly abnormal ALT and AST levels.

Crohn's disease and ulcerative colitis are diseases with chronic inflammation of the intestines. In these patients inflammation of the liver (hepatitis) or bile ducts (primary sclerosing cholangitis) also can occur, causing abnormal liver tests.

Rarely, abnormal liver enzymes can be a sign of cancer in the liver. Cancer arising from liver cells is called hepatocellularcarcinoma or hepatoma. Cancers spreading to the liver from other organs (such as colon, pancreas, stomach, etc) are called metastatic malignancies.

What medications cause abnormal aminotransferase levels?

A host of medications can cause abnormal liver enzymes levels. Examples include:

Pain relief medications such as aspirin, acetaminophen (Tylenol), ibuprofen (Advil, Motrin), neproxen (Narosyn), diclofenac (Voltaren), and phenybutazone (Butazolidine)

Anti-seizure medications such as phenytoin (Dilantin), valproic acid, carbamazepine (Tegretol), and phenobarbital

Antibiotics such as the tetracyclines, sulfonamides, isoniazid (INH), sulfamethoxazole , trimethoprim, nitrofurantoin, etc.

Cholesterol lowering drugs such as the "statins" (Mevacor, Pravachol, Lipitor, etc.) and niacin

Cardiovascular drugs such as amiodarone (Cordarone), hydralazine, quinidine, etc.

Anti-depressant drugs of the tricyclic type

With drug-induced liver enzyme abnormalities, the enzymes usually normalize weeks to months after stopping the medications.

Autoimmune hepatitis results from liver injury brought about by the body's own antibodies and defense systems attacking the liver.

Rarely, abnormal liver enzymes can be a sign of cancer in the liver. Cancer arising from liver cells is called hepatocellular carcinoma or hepatoma. Cancers spreading to the liver from other organs (such as colon, pancreas, stomach, etc) are called metastatic malignancies.

How are healthy people evaluated for mild to moderate rises in aminotransferase levels?

Evaluation of healthy patients with abnormal liver enzymes needs to be individualized. A doctor may ask for blood test data from old records for comparison. If no old records are available, the doctor may repeat blood tests in weeks to months to see whether these abnormalities persist. The doctor will search for risk factors for hepatitis B and C including sexual exposures, history of blood transfusions, injectable drug use, and occupational exposure to blood products. A family history of liver disease may raise the possibility of inherited diseases such as hemachromatosis, Wilson's disease, or alpha-1- antitrypsin deficiency.

The pattern of liver enzyme abnormalities can provide useful clues to the cause of the liver disease. For example, the majority of patients with alcoholic liver disease have enzyme levels that are not as high as the levels reached with acute viral hepatitis and the AST tends to be above the ALT. Thus, in alcoholic liver disease, AST is usually under 300 units/liter while the ALT is usually under 100 units/ liter.

If alcohol or medication is responsible for the abnormal liver enzyme levels, stopping alcohol or the medication (under a doctor's supervision only) should bring the enzyme levels to normal or near normal levels in weeks to months. If obesity is suspected as the cause of fatty liver, weight reduction of 5% to 10% should also bring the liver enzyme levels to normal or near normal levels.

If abnormal liver enzymes persist despite abstinence from alcohol, weight reduction and stopping certain suspected drugs, blood tests can be performed to help diagnose treatable liver diseases. The blood can be tested for the presence of hepatitis B and C virus and their related antibodies. Blood levels of iron, iron saturation, and ferritin (another measure of the amount of iron stored in the body) are usually elevated in patients with hemachromatosis. Blood levels of a substance called ceruloplasmin are usually decreased inpatients with Wilson's disease. Blood levels of certain antibodies (anti- nuclear antibody or ANA, anti-smooth muscle antibody, and anti-liver and kidney microsome antibody) are elevated in patients with autoimmune hepatitis.

Ultrasound of the abdomen are sometimes used to exclude tumors in the liver or other conditions such as gallstones or tumors obstructing the ducts that drain the liver.

Liver biopsy is a procedure where a needle is inserted through the skin over the right upper abdomen to obtain a thin strand of liver tissue to be examined under a microscope. The procedure is oftentimes performed after ultrasound study has located the liver. Not everybody with abnormal liver enzymes needs a liver biopsy. The doctor will usually recommend this procedure if 1) the information obtained from the liver biopsy will likely be helpful in planning treatment, 2) the doctor needs to know the extent and severity of liver inflammation/damage, or 3) to evaluate the effectiveness of treatment.

Liver biopsy is most useful in confirming a diagnosis of a potentially treatable condition. These potentially treatable liver diseases include chronic hepatitis B and C, hemachromatosis, Wilson's disease, autoimmune hepatitis, and alpha-1-antitrypsin deficiency.

How about monitoring aminotransferase levels?

What is usually most helpful is serial testing of AST (SGOT) and ALT (SGPT) over time to determine whether the levels are going up, staying stable, or going down. For example, patients undergoing treatment for chronic hepatitis C should be monitored with serial liver enzyme tests. Those responding to treatment will experience lowering of liver enzyme levels to normal or near normal levels. Those who develop relapse of hepatitis C after completion of treatment will usually develop abnormal liver enzyme levels again.

What about other liver enzymes?

Aside from AST and ALT, there are other enzymes including alkaline phosphatase, 5'-nucleotidase and gamma-glutamyltranspeptidase (GGT) that are often tested for liver disease.

We have restricted this consideration of liver enzymes to AST and ALT because they are biochemically related to each other and, more importantly, they are the two most useful liver enzymes.

Courtesy of Mayo Clinic & WebMD