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Overview of Hepatitis
An Emerging Public Health Threat
Over 4 million Americans are infected with hepatitis C. Most are unaware
of their infection. The National Institutes of Health (NIH) estimates that an additional
30,000 people are newly infected each year. Called "an emerging public health
threat," hepatitis C is a leading cause of cirrhosis and liver cancer. It is
also now the leading reason for liver transplantation in the United States.
Hepatitis A, B, and C
Of six known hepatitis viruses – A, B, C, D, E, and G – the most common are
hepatitis A, B, and C. Hepatitis A (HAV), the least serious form, does not progress
to chronic disease. A small proportion of individuals with hepatitis B – 5 to 10
percent – develops chronic disease.
Chronic hepatitis B (HBV) and C (HCV) are the most common causes of chronic viral
hepatitis in the United States, posing serious risks for long-term medical complications,
especially if left untreated. The American Liver Foundation estimates that HCV will
cause approximately 10,000 deaths annually, and HBV will cause 5,000 deaths. And
unlike other life-threatening illnesses, hepatitis usually claims individuals in
their most productive years; almost 50 percent of deaths occur before the age of
60.
About 85 percent of individuals who contract acute hepatitis C progress to chronic
disease. About 20 percent of those patients develop cirrhosis within 2 decades. Each
year after cirrhosis develops, the risk of developing cancer is 1 to 4 percent.
Although hepatitis A, B, and C remain diseases that warrant better preventive measures,
some progress has been made in the areas of better diagnostic techniques and more
effective treatments.
About 40 percent of patients with hepatitis C have a history of IV drug use. Forty
percent do not know the source of infection. The remaining 20 percent of hepatitis
C infections may be attributed to household contact with a known case of hepatitis,
sexual contact with multiple partners, transfusion-associated disease, or occupational
exposure.
Hepatitis C
Hepatitis C is a slow, progressive virus that can cause liver injury over
years, even decades, often without specific symptoms. Symptoms may include loss of
appetite, fatigue, decreased exercise tolerance, arthralgia, vomiting, stomach pain,
depression and – in rare cases – jaundice. Chronic fatigue is the most salient symptom.
The average incubation period for hepatitis C is usually 6 to 7 weeks, with a range
extending from 2 weeks to 26 weeks. Symptomatic illness develops in about 30 to 40
percent of individuals with acute infection; 20 to 30 percent will have jaundice.
Diagnosing Chronic Hepatitis C
Acute and chronic forms of hepatitis are diagnosed using a variety of tests
and assays. Persistent elevation in blood levels of the liver enzyme, alanine aminotransferase
(ALT), is the key biochemical marker of the disease. Also, HCV RNA, or genetic material
from the hepatitis virus, is detectable in the blood of most patients.
A systematic evaluation of a patient with abnormal ALT levels may proceed as shown:
Suggested Approach
to the Patient With Raised Serum Aminotransferase (>Two Times the Upper Limit
of Normal)
- Take a detailed history with
particular attention to potential hepatic insults
- Review list of therapeutic drugs
used
- Do a careful physical exam (liver,
spleen, etc.)
- Obtain serologic tests for viral
hepatitis (HBsAg, anti-HCV)
- Recheck ALT and AST at 3 and
6 months
- Review other conventional lab
tests
- Is serum albumin normal?
- Are serum globulins increased > 3 to 5 gms?
- Is serum cholesterol normal?
- Is CBC normal (hct, hgb, WBC, platelets)?
- Alcohol history
- Recent weight gain
Routine blood and serum tests for hepatic disease include:
Routine Blood/Serum Tests for Hepatic Disease
| Test |
Normal
Range |
| Alanine aminotransferase
(ALT) |
5 IU/L to
35 IU/L |
| Aspartate
aminotransferase (AST) |
5 IU/L to
40 IU/L |
| Alkaline phosphatase |
35 IU/L to
130 IU/L |
| Gamma glutamyl
transpeptidase (GGTP) |
10 IU/L to
48 IU/L |
| Gammaglobulin |
5 g/L to 15
g/L |
| Total bilirubin |
5 mmol to
17 mmol |
| Direct
bilirubin |
<5
mmol |
Regarding testing and the interpretation of results, it is useful
for healthcare providers to know the sequence of events following
infection with HCV. Within 2 to 4 weeks following infection, HCV RNA
can be found in the liver. This marker will precede the elevation
of ALT, which is not usually measurable until approximately 8 weeks
after infection. Second-generation and third-generation HCV antibody
tests may be positive after 8 weeks. Consequently, if a patient suspected
of being at risk does not demonstrate markers for hepatitis, the tests
should be repeated.
Liver biopsy is essential in chronic hepatitis patients because progressive stages
of chronic hepatitis are apparent in the erosive state of liver architecture. In
mild disease, the biopsy may show inflammation of the portal zones. Moderate disease
is shown by spotty areas of necrosis. In severe disease, necrosis of the limiting
edge of the portal zone is evident.
Major Risk Factors for Hepatitis B and C
HEPATITIS B
- Hemodialysis
- Patients of custodial institutions
for developmentally disabled
- Exposure to blood/blood clot
products
- Needle-stick injury
- Sexual activity with multiple
(heterosexual or homosexual) partners
- IV drug use
- Infants of HBV-positive mothers
- Tattooing
- Body piercing
HEPATITIS C
- Hemophilia patients who received
clotting agents prior to 1987
- Hemodialysis
- Organ transplant
- IV drug use
- Blood transfusion prior to 1992
- Needle-stick injury
- Tattooing
- Body piercing
- Sexual activity with multiple
partners
See "Available Treatment"
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