HEP C
DEFINITION
Hep C
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INCIDENCE
Accounts for 15-20% of acute hepatitis.
Accounts for 50% of all previously unexplained cirrhosis; may be
leading cause of chronic liver failure.
Risk Factors
Personal: IV drug abuse. Blood contacts. Sex =
less so; monogamous partners of infected people = rarely affected.
Comorbidities: Any organ / blood transfusion prior to 1992,
esp
if history of haemophilia before 1987.
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AETIOLOGY
Single strand RNA virus.
6 different genotypes.
Type Ib appears to be the most virulent.
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BIOLOGICAL BEHAVIOUR
Natural History
Parenteral transmission is common.
Sexual or vertical transmission is rare.
1-4 months incubation (mean 6-12 weeks)
No protective immunity, so can get reinfected.
Pathophysiology
Acute infection
95% don't go yellow.
5% experience a viral hepatitis similar to HAV.
Virtually no risk of acute liver failure.
Chronic Infection
High overall (65%-90%) risk of chronic liver disease.
This leads to chronic hepatitis, cirrhosis (usually 10-20 years
later,
and only in 25% of chronic patients), and possibly hepatoma (5%).
Some 5% may undergo spontaneous remission (uncertain).
Virology
Small enveloped RNA virus, encodes a single polyprotein.
Inherently unstable: rapid mutation of envelope proteins give many
different quasi-strains.
Pathology
See HBV card
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MANIFESTATIONS
Symptoms
Local
Acute infection
A few get an acute episode similar to HAV (see card).
- acute course are often less severe than HBV
Chronic infection
Chronic features of hepatitis.
Grumbles away.
Features of cirrhosis if relevant.
Features of hepatocellular carcinoma if relevant.
Signs
As for the above.
Observe
Icteric - sclera.
Palpate
Tenderness over liver area.
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INVESTIGATIONS
Biochem
Characteristically episodic serum transaminase elevations, with
intervening normal or near-normal periods.
Otherwise may be persistently elevated or remain normal.
Immunology
Diagnosis is confirmed with antibody in the serum, using ELISA or
PCA, as follows:
(labtestsonline.org)
1. Anti-HCV test.
- do this first.
- detects antibodies to the virus
- cannot distinguish past vs current infection
- if weakly positive, may be a false-positive
--> confirm with a RIBA test if weakly positive.
2. RIBA Test (Anti-HCV) via recombinant immunoblot assay
- confirms infection
--> if confirmed, proceed to:
3. HCV RNA Tests (Qualitative and Quantitative)
- qualitative says whether present or not. Seldom used.
- quantitative says the viral load, hence if current, active or not.
4. Viral genotyping
- for discerning the specific virus type.
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MANAGEMENT
Alpha interferon is being increasingly used.
Refer to a gastroenterologist.
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