**1.1 Natural history of liver cirrhosis and its complications**

The studies that provide more data on the natural history of cirrhosis are related to the evolution of chronic hepatitis by HBV and HCV. These are based on prospective, retrospective and cross studies, but are conditioned by factors that make difficult to establish absolute evidence on the natural history of the disease. (Serra MA., 2006)

Of those patients with HCV, 50% usually develop chronic liver disease including cirrhosis and liver cancer. It is estimated that 15% of chronically infected persons develop liver cirrhosis within 20 years. (Wiese M, 2005) However, there are individual differences. Currently it is known that 33% of patients develop cirrhosis in less than 20 years, while another 31% will need many more years in order to develop the same damage. (Serra MA 2006)

Usually it is a silent disease. Most patients are asymptomatic or have nonspecific symptoms until decompensation occurs. They can start with symptoms related to complications of liver failure or portal hypertension.

Ascites is the most common complication and of earlier onset. Once patients with cirrhosis develop ascites the prognosis worsens. It is estimated that approximately 50% of them could die within two years if they do not have a transplant. So, this is a major criterion for liver transplant evaluation in the United States and Europe. (Settle 2004, Sagnelli 2005)

Along with ascites, there may be other serious complication such as spontaneous bacterial peritonitis. In these cases, the probability of survival one year after this complication appears is only 40%. This is a strong reason for evaluating these patients as candidates for transplantation. (Corrao 1997) Similarly, other complications may appear such as hepatic encephalopathy and hepatic-renal syndrome. Both also worsen the prognosis. (Mandaya 2004)

Variceal hemorrhage occurs in 30 to 40% of patients with liver cirrhosis. In the past two decades, even with the improvement achieved in the treatment and in the prognosis after bleeding, mortality at six weeks is still high. It is estimated between 15 and 30% in patients with stage C of Child-Pugh. (Hands 2008)

After a first episode of hepatic encephalopathy the survival of cirrhotic patients is 42% in the first year, and 23% in the following three years. (Mendez-Sanchez 2005)

Hepatocellular carcinoma is another major complication and can occur at any stage of cirrhosis. It is recognized as the leading cause of death in the compensated phase, especially in patients with HCV. (Capocaccia R, 2007; Perz, J.F, 2006)
