Cirrhosis : Basics and laboratory diagnosis

Dr David Howdijam *

Abdominal computed tomography of a 3 year old child showing liver cirrhosis in transverse section :: Pix - Wikipedia/Christaras A

Cirrhosis is severe scarring of the liver caused by chronic liver disease. As healthy liver tissue is damaged over a long period of time, it is replaced by scar tissue, affecting the structure of the liver and decreasing its ability to function. Cirrhosis is seen with a variety of chronic liver diseases and may take years to develop.

The liver is a vital organ located in the upper right-side of the abdomen. Among other functions, it helps convert nutrients from food into essential blood components, produces many of the factors necessary for normal blood clotting, metabolises and detoxifies substances that would otherwise be harmful to the body, and produces bile – a fluid necessary for digestion of fats.

With cirrhosis, the structure of the liver changes, forming nodules of cells surrounded by fibrous tissue. This tissue does not function like healthy liver tissue and can interfere with the flow of blood and bile through the liver. As cirrhosis progresses, it can begin to affect other organs and tissues throughout the body.

Causes of cirrhosis : When injury to the liver is acute or liver damage is limited, the liver can usually repair itself. It is usually not short-term damage that causes cirrhosis, but repeated injury or damage occurring over many years that can lead to the development of cirrhosis.

Causes are wide-ranging but generally fall into one of several categories:
1) Alcoholism – excessive alcohol use over time can lead to alcoholic liver disease and cirrhosis.
2) Associated with hepatitis, such as viral hepatitis, autoimmune hepatitis and non-alcoholic fatty liver disease (NAFLD).
3) Biliary – obstruction and/or damage to bile ducts.
4) Cardiac – congestive heart failure over time can cause liver damage and cirrhosis.
5) Metabolic or inherited – these include diseases such as cystic fibrosis, haemochromatosis, Wilson disease, Fanconi syndrome.
6) Drug related (other than alcohol).
7) Unknown – in about 10% of cases of cirrhosis, the cause is not known.

Tests for cirrhosis : It is important to detect cirrhosis as soon as possible since significant damage may occur with few or no symptoms. If the cause of liver damage can be eliminated or controlled, further scarring will stop and some existing scars may actually resolve. While blood tests can detect liver injury, there is no single test that can be used to diagnose cirrhosis. A liver biopsy is considered the “gold standard” for diagnosing cirrhosis, but the procedure is invasive and will not detect every case.

Routine laboratory tests may be done to detect liver damage and/or scarring and to evaluate its severity, particularly, if the individual has some risk factors or developing cirrhosis. Additional tests may be performed to help diagnose the underlying cause and to monitor the affected individual’s health over time. This can include monitoring for possible development of hepatocellular carcinoma (liver cancer).

(1) Routine tests : Liver injury may be first detected in those who do not have symptoms during general health check-up.

A liver panel (liver function tests) may be performed when someone has symptoms that may be due to liver injury.

The panel includes several tests: Alanine aminotransferase (ALT), an enzyme found mainly in the liver; may be moderately elevated with liver injury, including cirrhosis. Aspartate aminotransferase (AST), an enzyme found in the liver and other places; may be moderately elevated with liver injury, including cirrhosis.

Alkaline phosphatase (ALP), an enzyme related to the bile ducts; often normal. Gamma-glutamyl transferase (GGT), an enzyme found mainly in the liver; often normal. Total bilirubin measures all the bilirubin in the blood; increased with many liver diseases but may be normal in cirrhosis until it is far advanced. Albumin, a protein made by the liver, may be decreased.

If any of these tests are abnormal, then they will be further investigated. Typically, the pattern of results is more significant than the result from one or few of these tests. Complete Blood Count (CBC) may be done to evaluate a person’s red and white blood cells and platelets; anaemia may be present if bleeding has occurred and platelets are often decreased with cirrhosis.

Prothrombin Time (PT/INR) most clotting factors are produced by the liver; this test evaluates clotting function and results may be prolonged with cirrhosis. Many of the tests mentioned above may be used to monitor the progression of cirrhosis. As condition worsens, results may become increasingly abnormal.

Follow up testing : Hepatitis B and Hepatitis C testing may be ordered to help diagnose the underlying cause of chronic liver disease. If ascites is present, peritoneal fluid analysis may be performed. Liver biopsy is also done to evaluate the cells of the liver for detecting cirrhosis.

(2) Radiological investigations

Other procedures and imaging tests may be useful:
Ultrasound – done to help evaluate non-alcoholic fatty liver disease (NAFLD), and if diagnosed with cirrhosis, to monitor for development of liver cancer. FibroScan (transient elastography) – to evaluate the degree of liver fibrosis by measuring liver stiffness; the investigation is rapid, non-invasive and reproducible. FibroScan is usually beneficial for diagnosis of cirrhosis during very early stage.