Hepatitis C Information Central

Volume 1 issue 4

Hep C: Progression, Pathology

Natural History:

Hepatitis C is still a recently diagnosed disease recognized only nine years ago. For this reason, patients have not been able to be followed long enough prospectively to truly know the natural history. Statistics are gained from retrospective analysis and some small short-term prospective studies but the statitstics are still somewhat uncertain.

The course may fluctuate in activity. Specialists in the field of Hep C recognize that enzyme levels fluctuate and the degree of hepatic inflammation may well fluctuate (similar to other chronic viral illnesses such as Herpes Simplex).

The host and environmental factors that influence the course and progression are:
Factor: Duration of infection
Influence on Outcome: Longer duration may increase rate of progression

Factor: Age of infection
Influence on Outcome: Persons infected over age 50 may have more active disease

Factor: Gender
Influence on Outcome: Women may have less active course than men

Factor: Route of infection
Influence on Outcome: Transfused-related Hep C acquired may have more active course than IVDU acquired

Factor: Hemophilia
Influence on Outcome: Some limited studies suggest less fibrosis in hemophiliacs

Factor: Diabetes
Influence on Outcome: Increased risk of acquiring Hep C

Factor: Iron overload
Influence on Outcome: Increased rate of progression of Hep C

Factor: Alcohol use/abuse
Influence on Outcome: Increased rate of progression

Factor: HBV co-infection
Influence on Outcome: No increased progression to cirrhosis but increase in hepatocellular carcinoma (HCC)

Factor: HIV co-infection
Influence on Outcome: Faster progression to cirrhosis and higher rate of cirrhosis

Factor: Smoking
Influence on Outcome: Possible increased risk of HCC

Factor: Immunosuppression
Influence on Outcome: Steroids do not seem to make Hep C more active

According to present knowledge, the rate of progression is as follows:

- number of acute cases becoming chronic: 80 - 85%

- number of chronic cases developing cirrhosis:
- at 10 years post infection = 5 - 6%
- at 20 years post infection = 12 - 15%
- at 30 years post infection = 18 - 25%

- number of cirrhotics (from Hep C) developing decompensation:
- at 10 years post infection = 0.7%
- at 20 years post infection = 3 - 4%
- at 30 years post infection = 5 - 7%

- number developing Hep C related HCC:
- usually only occurs in patients after development of cirrhosis

- occurrence rate after development of cirrhosis is approximately:
* 3 years: 4% developing HCC
* 5 years: 7% developing HCC
* 10 years: 14% developing HCC
- average time to development is 28 years after infection

What about a liver biopsy?

A liver biopsy is currently the most accurate way of determining activity of disease, extent of fibrosis and assessing prognosis. The CASL (Canadian Association for the Study of the LIver) consensus statement is that "A liver biopsy is not mandatory but is strongly recommended". Because of imperfect treatment, a liver biopsy can assist greatly in making the decision about treatment. If the time of infection is known, the progression from that point to the time of the biopsy will give valuable information about previous and probably future progression. A liver biopsy is relatively safe, particularly the ultrasound guided biopsy.

Statistics relative to biopsy are:
risk of pain: 1/30
risk of serious bleeding: 1/1,000 - 1/3,000
risk of death: 1/10,000 - 1/17,000

Risk of death in the past tended to occur in patients with cirrhosis and with the use of a larger biopsy needle. With ultrasound guidance, pre-biopsy group and screen and smaller needles, death from bleeding should not occur.

Pathology:
The important features in the liver biopsy are the amount of inflammation and the degree of fibrosis. While a number of classifications are used, a practical one is the Ludwig Classification. Note: what was formerly called piecemeal necrosis or limiting plate necrosis is now usually called "interface hepatitis".

Inflammation

Lobular:
Grade 0 no inflammation
Grade 1 minimal, no necrosis (inflammatory cells within the lobule)
Grade 2 moderate inflammatory cells with occasional liver cell necrosis
Grade 3 marked inflammation with severe focal liver cell necrosis
Grade 4 extensive inflammation with bridging necrosis

Fibrosis:
Stage 1 none or mild peri-portal fibrosis
Stage 2 peri-portal fibrosis with/without extension and portal-portal bridging
Stage 3 portal-central bridges but no nodular formation
Stage 4 probable or definite cirrhosis

Other Features:
- lymphoid nodules - fairly specific to Hep C
- damage to small bile ducts
- fatty deposition - fairly frequent

The Hepatitis Knowledge Newsletter is edited by F.H. Anderson, MD., FRCP(C), Natalie Rock, BSN, RN, Susan Campbell, RN. Room B-206, Dept. of Medicine, Van. Gen. Hosp. 855 W 12th. Vancouver V5Z 1M9. Phone:(604)209-9976 Fax: (604)875-4429.

The Newsletter is supported by an educational grant from Schering Canada Inc. and GlaxoWellcome Canada.