_ The liver biopsy is an important diagnostic tool because it is considered the most precise procedure we have today for evaluating the health of the liver by measuring the degree of liver inflammation and staging of fibrosis for predicting disease progression and treatment outcome. There are a variety of ways to interpret a liver biopsy. The most common scoring methods include Metavir and the histologic activity index (HAI) also called the Knodell. It is important to remember that the length of the liver specimen and the knowledge of the professional reading the biopsy can influence the interpretation of the report.
Metavir Scoring
_ The Metavirscoring system was specially designed to be used as a grading and a staging system. The grade gives an indication of the activity or amount of inflammation and the stage represents the amount of fibrosis or scarring.
The grade is assigned a number based on the degree of inflammation,
which is usually scored from 0-4 with 0 being no activity and 3 or 4
considered severe activity. The amount of inflammation is important
because inflammation somewhat correlates with the development of
fibrosis. The fibrosis score is also assigned a number from 0-4:
0 = no scarring
1 = minimal scarring
2 = scarring has occurred and extends outside the areas in the liver that contains blood vessels
3=bridging fibrosis is spreading and connecting to other areas that contain fibrosis
4=cirrhosis or advanced scarring of the liver
Knodell Score
_ The
Knodell score or histologic activity index (HAI) is also commonly used
to stage liver disease. It is somewhat of a more complex process, but
some experts believe that it is a better tool for defining the extent of
liver inflammation and damage because it provides more information
about various aspects of inflammation and scarring. It is composed of
four individually assigned numbers that make up a single score. The
first component (periportal and/or bridging necrosis) is scored 0-10.
The next two components (intralobular degeneration and portal
inflammation) are scored 0-4. The combination of these three markers
indicates the amount of inflammation in the liver:
0 = no inflammation
1-4 = minimal inflammation
5-8 = mild inflammation
9-12 = moderate inflammation
13-18 = marked inflammation
The fourth component indicates the amount of scarring in the liver and
is scored from 0 (no scarring) to 4 (extensive scarring or cirrhosis).
Summary:
_ Information about the grade and stage of liver disease is helpful for
the healthcare provider and the patient in guiding medical management.
For example, treatment is usually indicated if the Metavir score is
greater than or equal to 2 or the Ishak/Knodell score is greater than or
equal to 3. It is important to know this information in order to help
guide management and treatment of liver disease. For example, if a
medical provider is able to estimate the approximate time when someone
became infected with liver disease, the results of the biopsy will give
an indication of the rate of disease progression:
For people
with moderate to severe liver damage it is generally recommended that a
more aggressive treatment approach is warranted.
For people with a milder form of liver disease a watch and wait approach is usually recommended.
However, given that people with milder liver disease respond better to
current therapies, some experts believe that even people with milder
forms of liver disease should be treated.
Sound
confusing? Probably the best advice is to work closely with your medical
provider to find out whether treatment is needed or not!