Page 208 - Medicine and Surgery

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204 Chapter 5: Hepatic, biliary and pancreatic systems

Acute infection is diagnosed by the presence of HCV If hepatitis D occurs in patients carrying hepatitis B,

RNA in the serum, using PCR. A positive PCR in- i.e. a super-infection, it may precipitate an acute hep-
dicates current viraemia whereas a negative test with atitis or convert a mild chronic disease to fulminant
positive anti-HCV antibodies suggests non-viraemic hepatitis. HDV super-infection has a strong tendency
infection, transient absence of viraemia or recovered (10–40%) towards chronic progressive disease, lead-
infection. Quantification of the viral load may be of ing to an increased risk of rapidly developing cirrhosis
use in tailoring treatment. and hepatocellular carcinoma.
Liver biopsy is used for assessing liver inflammation,

potential progression of fibrosis and the presence or
Investigations
absence of cirrhosis. Finding antibodies to HDV (IgM or IgG) is diagnostic.
Alternatively, a cDNA probe can be used to detect HDV
Management in the blood, and HDAg can be detected in liver cells
Counselling regarding transmission is essential. In acute using immunofluoresence.
infection supportive treatment may be necessary. Com-
bination therapy with pegylated interferon α and rib-
Management
avirin is recommended for the treatment of people aged
There is no vaccine for hepatitis D; however, vaccination
18yearsandoverwithmoderatetoseverechronichepati-
against hepatitis B will prevent hepatitis D infection. In-
tis C (histological evidence of significant scarring and/or
terferon α can be used to treat patients with chronic
significant necrotic inflammation). If ribavirin is con-
hepatitis B who also have hepatitis D infection.
traindicated or not tolerated, pegylated interferon α
monotherapy should be used. Patients with severe cir-
Prognosis
rhosis may require liver transplantation. There is no
Recovery from hepatitis B leads to clearance of hepatitis
available vaccine.
D also. However, chronic hepatitis D infection has a poor
prognosis.
Hepatitis D
Definition Hepatitis E
Hepatitis D virus (HDV) or delta agent is a virus that
Definition
only causes hepatitis in conjunction with hepatitis B.
Hepatitis E virus (HEV) is a member of the group of
hepatotrophic viruses, which cause hepatitis.
Aetiology/pathophysiology
Hepatitis D, a single stranded RNA virus, has a genome
which does not encode for its own protein coat. It there- Incidence/prevalence
Epidemics of tens of thousands of cases in developing
fore has to use proteins made by the HBV. It is therefore
world.
not pathogenic in the absence of HBV replication. Un-
like HBV, it has a direct cytopathic effect, which may
contribute to the clinical features. Any patient at risk of Geography
hepatitis B is at risk of hepatitis D, particularly intra- Cause of water-borne epidemics in the Indian subconti-
venous drug users. nent and North Africa.

Clinical features Aetiology/pathophysiology
Two patterns of disease are seen: HEV is an ssRNA virus of the calicivirus group. Hepatitis
WhenhepatitisBandDsimultaneouslyinfectthehost E, like hepatitis A, is transmitted via the faecal–oral route

aco-infectionoccurs.Theresultinghepatitisisofvari- and has an incubation period of 2–9 weeks. It causes a
able severity, but is more likely to cause fulminant self-limiting acute hepatitis, with no chronic or carrier
hepatic failure. The chronic carrier state is rare. state.