Cirrhosis is the medical term for extensive tissue loss and scarring in the liver. A variety of injuries or diseases involving the liver cause this scarring, or fibrosis, which is irreversible once it has advanced to its late stages. Measuring liver enzymes in the blood is one part of a battery of tests used in the diagnosis and monitoring of cirrhosis.
Cirrhosis
Widespread long-term inflammation or other damage to the liver, with resulting death of liver cells and scar tissue formation, leads to the development of cirrhosis over time. Common conditions that can eventually lead to cirrhosis include chronic heavy alcohol use, viral hepatitis, genetic disorders such as hemochromatosis, some biliary tract diseases, drugs and toxin exposure. Inflammation and cell injury releases liver enzymes into the blood in amounts roughly proportional to the extent of damage to the liver.
Diagnosis of Cirrhosis
The underlying cause of the liver damage and the severity of scarring in cirrhosis influence the types of symptoms that might occur. Common symptoms of cirrhosis include loss of appetite, fatigue, nausea, yellowing of the skin and eyes, dark urine and abdominal swelling. Measurement of liver enzymes and other blood markers, radiologic studies such as ultrasound or CT scan, and in some cases needle biopsy of the liver are performed in order to reach a diagnosis. A physician performing a needle biopsy inserts a small-diameter hollow needle through the skin and into the liver, removing a thin cylinder of tissue for examination under a microscope.
Liver Function Tests
A wide variety of blood tests are available to assess liver function and progression of liver disease. These tests include the enzymes alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase, according to the book "Clinical Diagnosis and Management by Laboratory Methods." Enzyme levels in the blood are elevated during times of active liver damage, with the degree of elevation depending on the severity of changes at the time the blood is drawn. Other blood tests such as albumin, blood clotting studies and ammonia are usually normal during the early stages of cirrhosis. Bilirubin levels can be normal or elevated.
Late Stage Cirrhosis
The liver's ability to perform its usual functions becomes seriously compromised when scarring from cirrhosis has replaced over 80 percent of the liver tissue. With fewer liver cells remaining to produce and release enzymes, transaminase levels drop to normal or below normal. Protein synthesis similarly decreases, causing albumin and the blood clotting proteins to drop as well. Ammonia levels and bilirubin rise, as the liver loses its ability to efficiently remove them from the system.
Treatment
Once extensive liver injury has occurred and the normal tissue is replaced by scarring, the damage cannot be reversed. The primary goal of treatment for cirrhosis centers on avoiding even further damage and worsening of liver function. Discontinuing the use of alcohol and drugs that can cause liver damage is important, as is good nutrition and following any dietary restrictions recommended. Surgery to treat complications might be necessary, and liver transplant is an option in some cases. Liver function tests should be performed periodically to check for progression of the disease.
References
- MayoClinic.com: Cirrhosis
- FamilyDoctor.org: Cirrhosis and Portal Hypertension
- "Clinical Diagnosis and Management by Laboratory Methods", Nineteenth Edition; John Bernard Henry M.D., Editor; 1996
