The natural history of infection with hepatitis C
Recreated from: http://www.who.int/csr/disease/hepatitis/whocdscsrlyo2003/en/index.html

 The period immediately after infection with the hepatitis C virus is the so-called ‘acute phase’. Acute hepatitis C often has no symptoms, but people who do show symptoms usually experience fatigue (extreme tiredness), jaundice (yellowish eyes and skin) and/or dark urine (bile in the urine).

In 10–30% of acute hepatitis C infections, the virus is spontaneously cleared without treatment, meaning that it is no longer detectable in the blood.¹ In these cases, people often make a full recovery and are sometimes not even aware that they have been exposed to the virus. However, they can still test positive for antibodies to the hepatitis C virus. Overall, 70–90% of people who are infected with the hepatitis C virus go on to develop chronic hepatitis C.¹

In chronic hepatitis C, the virus continues to cause liver damage over long periods of time. As many people with chronic hepatitis C remain asymptomatic (symptom-free) for 20-30 years, the infection often continues undiagnosed. Because patients may not realise they have hepatitis C, they do not receive the appropriate management or advice to help reduce or prevent further liver injury. In a chronic infection, some people may develop specific syndromes (groups of symptoms) due to hepatitis C that are not related to the liver (for example, joint problems or skin complaints).

The risk of significant liver damage increases the longer hepatitis C goes untreated. Liver damage occurs in the form of fibrosis, where the liver becomes scarred, and then more severely in the form of cirrhosis, which is largely irreversible scarring that replaces normal liver tissue and directly affects how the liver works. Cirrhosis occurs in up to 20% of people with chronic hepatitis C.¹

Generally, fatigue is one of the most common symptoms of chronic hepatitis C. Symptoms that occur at advanced stages of liver cirrhosis, where the liver stops working properly (decompensated cirrhosis), include one or more of the following:

• Ascites
  • swelling of the abdomen due to liquid in the cavity surrounding the digestive organs
• Confusion/encephalopathy (disorder or disease of the brain affecting function)
  • resulting from failure of the liver to clear toxins from the gut
• Variceal haemorrhage
  •  potentially severe bleeding from the throat or stomach
• Bruising/bleeding
  • due to impaired production of blood clotting factors by the liver
• Oedema
  • swelling – often due to low protein levels in the blood.

In addition, 1–5% of people with chronic hepatitis C go on to develop a form of liver cancer (hepatocellular carcinoma).¹

It has been estimated that 5–7% of people infected with hepatitis C virus may die as a consequence of their infection.¹ One estimate concluded that the annual worldwide mortality rate due to infection with hepatitis C was 366,000 deaths, with 58% due to cirrhosis and 42% due to hepatocellular carcinoma.²

Hepatitis C is a leading cause of liver transplantation in developed countries and the most common chronic blood-borne infection in the United States.