PEDBASE.org - The Pediatric Database - Detailed information of HEPATITIS D

HEPATITIS D

DEFINITION:

An infectious disease of the liver caused by the hepatitis D virus (HDV) resulting in an acute and chronic hepatitis.

EPIDEMIOLOGY:

incidence: ?
age of onset:
- ?

risk factors:
- IV drug users, hemophiliacs, institutionalized mentally retarded patients (but not homosexuals)
- epidemics of superinfection have been reported in South America

PATHOGENESIS:

1. Etiology

1. Hepatitis D Virus

a single-stranded circular RNA satellite virus 35 nm in diameter
a double-shelled particle with an external coat composed of Hepatitis B surface antigen (HBsAg) provided by the helper Hepatitis B virus (HBV) genome and an internal coat composed of delta antigen provided by the HDV genome - thought of as a defective RNA virus that can replicate only in the presence of an acute or chronic HBV infection - routes of infection:
- usually parenteral
- occasionally through intimate sexual contact
- perinatal infection is rare

2. Hepatitis D

occurs with two types of HBV infection:

1. Coinfection

simultaneous onset of acute HBV & HDV infection

2. Superinfection

a chronic HBV carrier is infected with HDV

2. Pathogenesis

infection -> 21-90 day incubation period -> hepatocellular damage (elevated ALT) -> hepatitis -> HBsAg is cleared and HDV replication ceases -> acute liver disease resolves

CLINICAL FEATURES:

1. Prodrome

arthritis and rash may be present

2. Hepatitis

acute onset with duration of illness ranging from several weeks to months
while the preicteric phase can last up to 5 days, the icteric phase lasts from days to months with a mean of 8-11 days in children

1. Preicteric Phase

1. Fever

may be absent in children but last up to 5 days in adolescents
ranges from 37.8-40 C

2. Accompanying Signs/Symptoms

abdominal pain
anorexia
headache
lethargy
nausea/vomiting
hepatomegaly (tender)
lymphadenopathy
splenomegaly

2. Icteric Phase

1. Jaundice

is a component of coinfection but not superinfection
transition to the icteric phase is marked by the disappearance of preicteric signs/symptoms in young children but the exacerbation of these signs/symptoms in older children and adolescents
accompanied by dark urine (biliuria) +/- clay-coloured stools
may be anicteric in infants and children less than 3 years of age

3. Hepatic Complications

1. Chronic Persistent Hepatitis

a pathological diagnosis based on finding an inflammatory process on liver biopsy involving only the portal areas - anicteric and asymptomatic except for mild hepatomegaly
moderate elevation of ALT
lasts longer than 6 months and may resolve after years or progress to chronic active hepatitis

2. Chronic Active Hepatitis

chronic and recurrent episodes of jaundice and elevated
ALT and AST
may progress to cirrhosis +/- portal hypertension with ascites

3. Liver Failure

1. Fulminant Hepatitis

liver failure occurring within days to 4 weeks after onset of acute hepatitis
associated with mental confusion, emotional instability, restlessness, bleeding, and coma
those patients with superinfection are at greatest risk for development of fulminant hepatitis

2. Subacute Hepatitis

liver failure occurring 1-3 months after the onset of acute hepatitis

INVESTIGATIONS:

1. Coinfection

1. Serum

1. Alanine Aminotransferase (ALT)

striking rise in level after the incubation period, is biphasic, and can last up to 3 months

2. Bilirubin

transient elevation associated with the peak in ALT levels lasting for about 1 month

3. Serology

anti-HDV is detected at the onset of signs/symptoms and is initially predominantly IgM but then later is exclusively IgG (after 12 months)
the high levels of IgG do not persist but are transient
anti-HBs begins to rise after 6 months

4. Viremia

HBsAg appears during the latter part of the incubation period followed by HDV RNA and last 3.5 and 2 months, respectively

2. Superinfection

1. Serum

1. Alanine Aminotransferase (ALT)

striking rise in level after the incubation period and persists

2. Bilirubin

there does not appear to be an elevation in bilirubin levels

3. Serology

anti-HDV responds the same way as with the coinfection except that high levels of the IgG persist
there is no rise in anti-HBs

4. Viremia

HBsAg is present before superinfection and persists
HDV RNA appears during the signs/symptoms and persists

MANAGEMENT:

1. Supportive

symptomatic

2. Prognosis

can result in chronic hepatitis, liver disease, and/or a carrier state (yet there is a very low risk of perinatal infection)
mortality from a fulminant hepatitis is:
- 2-20% with coinfection
- up to 30% with superinfection

Pediatric Database - HEPATITIS D

Pediatric Organization - Pedbase [at] Gmail.com