Infectious hepatitis is a syndrome characterized by injury (inflammation
or death) to hepatocytes. The process may be self-limiting or may
lead to fibrosis, cirrhosis, and neoplastic changes. Clinically,
the hepatocellular insult is manifested by elevation of serum aminotransferases
(alanine aminotransferase (ALT) and aspartate transaminase (AST)).
Typically, the alphabetically designated hepatitis viruses (A–G)
and, in particular, hepatitis viruses A, B, and C are those generally considered
by the clinician when evaluating a child with hepatitis (Table 24–1).
However, many other viral agents such as Epstein–Barr virus
(EBV), cytomegalovirus (CMV), coxsackieviruses, echoviruses, West
Nile virus, etc., have the potential to infect the liver and cause
clinical or subclinical hepatitis (Table 24–1). This chapter
will focus on the hepatitis A, B, and C viruses, the major causes
of viral hepatitis in children.
Table 24–1. Viruses Associated with Hepatitis |Favorite Table|Download (.pdf)
Table 24–1. Viruses Associated with Hepatitis
|Human immunodeficiency virus||Retroviridae||RNA|
|Herpes simplex viruses types 1 and 2||Herpesviridae||DNA|
|• Coxsackieviruses A and B|
|• Numbered enteroviruses|
|West Nile virus||Flaviviridae||RNA|
Hepatitis A virus (HAV) is a small nonenveloped RNA virus in
the genus Hepatovirus within the Picornaviridae family.1 Transmission
of HAV occurs predominantly via a fecal–oral route. Because
the majority of HAV infections in children result in subclinical
disease, children play a major role in the transmission of the virus
within communities. Outbreaks of hepatitis A occurring in child
care centers are well known to occur. Common-source outbreaks through
the ingestion of contaminated food or water have also been well
documented. Transmission of HAV via transfusion of blood or blood
products occurs occasionally when donors are sampled during the
viremic phase of the infection. High-risk groups for the acquisition
of HAV infection include travelers to developing countries, men
who have sex with men, users of injection and noninjection drugs,
and individuals working with nonhuman primates.
With the advent of recommendations for vaccination of high-risk
individuals and children residing in states with a high prevalence
of HAV infection, followed by the more recent recommendation of
routine vaccination of all children 1 year of age, the incidence
of hepatitis A infections in the United States has decreased significantly.2 In
2007, the reported incidence of hepatitis A infection was 1 case
per 100,000 persons in the United States. During that year, the
lowest rates of infection occurred among children <5
years of age. Taking into account asymptomatic infections and underreporting,
it was estimated that 25,000 new cases of hepatitis A occurred that
year.3 This represented the lowest incidence ever recorded.
Hepatitis B virus (HBV) is a DNA virus in the Hepadnaviridae family.4 Replication
of HBV occurs in an asymmetric ...