Chronic hepatitis is defined
as inflammation of the liver persisting for more than 6 months.
Chronic hepatitis it is not
a single disease but a syndrome with many causes.
It is clinically defined as
persistent abnormal liver function tests of hepatitic type of 6 months'
There are three main types
of chronic hepatitis, each of which carries a different risk of developing into
In chronic active hepatitis
(CAH), which is also known as 'chronic aggressive hepatitis', inflammatory
changes are associated with continued necrosis of liver cells.
The main complication of this pattern of chronic hepatitis is the development of
In some cases, necrosis extends from one portal area to another (bridging
necrosis) early in the course of disease and is an index of likely rapid
progression to cirrhosis.
In chronic persistent
hepatitis (CPH), inflammation is confined to the portal tracts, and necrosis of
liver cells is not seen.
Generally this type of chronic hepatitis is not associated with development of
progressive fibrosis or cirrhosis. However, some patients who exhibit this
pattern of inflammation and are HBeAg-positive (indicating active viral
replication) progress to
chronic active hepatitis, with seroconversion to anti-HBeAg positivity and
development of cirrhosis.
Patients with CPH due to HCV infection may also develop progressive disease with
In chronic lobular hepatitis
(CLH) there is inflammation of portal tracts, with spotty parenchymal
inflammation but no piece-meal necrosis.
This pattern of chronic hepatitis is
usually associated with a viral aetiology.
Cases that are associated with
hepatitis B infection and are positive for HBeAg may later develop chronic
Other cases generally do not progress to cirrhosis.
Histologically there is
lymphocytic inflammatory infiltration in portal tracts, which spills over into
the adjacent parenchyma.
Piecemeal necrosis of liver cells is seen at the
interface with the connective tissue of the portal tract. With time,
this necrosis extends, star-like, from portal areas and, in late stages,
progresses to bridging fibrosis
between adjacent portal tracts.
In chronic persistent hepatitis, lymphoid infiltration is seen in portal tracts.
However, in contrast to chronic active hepatitis, there is no necrosis of liver
cells in the limiting plate.
Chronic hepatitis following
viral infection may progress to cirrhosis
Following infection by
hepatitis B or hepatitis C viruses, a proportion of patients develop persistent
viral infection and chronic hepatitis.
In hepatitis B infection
liver cells have a characteristic 'ground glass' appearance.
In these cases, evaluation of HBeAg and anti-HBeAg can be used to predict likely
progress to cirrhosis.
Patients who have chronic active hepatitis are at risk of developing cirrhosis.
An important complication of chronic infection by hepatitis B and C is the
development of hepatocellular carcinoma.
Some patients present with advanced chronic liver disease and no clinical
history of acute hepatitis, yet can be shown to have viral infection by serology
and liver biopsy. In these cases it is assumed that there has been sub-clinical
In chronic hepatitis due to
hepatitis B infection, liver cells accumulate HBsAg in the cytoplasm, which
appears homogeneous, pale and glassy. These so-called 'ground glass' hepatocytes
may be immunostained by antibodies to HBsAg, where they are stained brown.