Progression and stages of hepatitis C

The natural history of hepatitis C looks at the likely outcomes for people infected with the virus if there is no medical intervention. However, the process of trying to predict how hepatitis C will affect the body over time and get a picture of the likely disease progression is complicated by a number of factors:

The laboratory test to identify the virus was only developed in 1989 so this is a relatively short time in which to study a disease. Although a great deal has been learnt about what can take place during the first 20 years of infection with hepatitis C, the prognosis from the third decade on remains largely uncharted.

In order to get a picture of likely progression over time it is necessary to know when people were infected. This is problematic as many people with HCV do not know when or how they were infected.

One of the main conundrums about HCV infection is that people have such different outcomes and experiences. While some people clear the virus in the very early stages, most will develop a long term or chronic infection. The course of the disease then is very variable. One person may have no liver damage after twenty years while another person will develop cirrhosis and sometimes liver failure or liver cancer.

The range and degree of symptoms also varies significantly. Many people remain asymptomatic (without symptoms) for years, while others will experience fatigue, depression, digestive problems and other symptoms among the many varied extra-hepatic (outside of the liver) complications of hepatitis C infection. Confusingly the symptoms people suffer are not necessarily an indication of whether they have liver damage or not. One person may have almost no liver damage and yet their quality of life is severely affected by symptoms, while somebody with extensive scarring of the liver may be symptom free. Existing blood tests for example viral load, liver enzyme levels, or HCV genotype also cannot reliably forecast the outcome of untreated HCV infection.

Despite these variations and difficulties an increasing amount has been learnt about how the disease does generally progress.

Hepatitis C is considered to have four stages:

The Acute Stage
The Chronic Stage
Compensated Cirrhosis
Decompensated Cirrhosis

Overview of the Stages

The period immediately after infection is called the acute phase. This lasts about six months. If the immune system does not manage to clear the virus by then the disease is considered to have moved into a long-term or chronic phase.

Hepatitis C is classified as a liver disease because of the damage it causes to the liver, however the virus affects other body systems and causes symptoms, illnesses and complications outside of the liver.

Doctors have previously tended to focus mainly on the state of your liver as opposed to symptoms you feel or other complications caused by the virus because they have often been seen as unconnected or unrelated. This has meant that they have been given less attention and been studied less.

The effects of Hepatitis C are described in terms of the changes to the liver as scarring develops. This progression moves from the initial inflammation of the liver caused by the virus hijacking, infecting and killing off liver cells through to the gradual scarring (fibrosis)and then hardening of liver tissue (cirrhosis). Throughout this progression the immune system plays a highly influential role both in stemming the disease but also in accelerating scarring of the liver.

Cirrhosis is severe scarring that alters the structure of the liver and over time will seriously undermine the livers ability to function. Cirrhosis is classified as being either compensated or de-compensated. If the liver can continue to carry out most of its functions despite extensive scarring then this is known as compensated cirrhosis (meaning that the liver can compensate for the damage) If the livers functions are seriously affected then this is called decompensated cirrhosis. The most serious symptoms of this stage are:

• Portal Hypertension, (when blood cannot properly flow into the liver and causes bleeding from distended veins (varices) in the oepsphagus and the build up of abdominal fluid (acites)
• and Hepatic Encephalopathy. If blood is forced to bypass the liver it is not filtered for poisons and toxins and there is risk of serious mental confusion leading to coma.
  (see decompensated Cirrhosis for more on all these symptoms)

Cirrhosis also significantly increases the risk of developing liver cancer. This can develop from either compensated or decompensated cirrhosis.

Recent studies suggest that chronic infection with HCV will almost invariably result in cirrhosis. It is the time that this takes that varies. For those people who develop a chronic or long term infection (between 70-80% of those infected with HCV) around 20-30% will develop cirrhosis within 20 years. For some it may be quicker but for others it may take up to sixty years so they may well die of unrelated diseases beforehand.