Viral Hepatatitis & Gastroenteritis Flashcards
Viral hepatitis
A systemic disease primarily involving the
liver
Produce a chronic inflammation of the liver,
gastrointestinal symptoms such as nausea,
vomiting & jaundice
Hepa A virus
HAV (prototype of genus Hepatovirus)
aka enterovirus-72
Picornaviridae
Causes hepatitis A (infectious)
Fecal-oral
Findings:
Initial symptoms: N/V, diarrhea, abdominal
discomfort, anorexia, fever, chills
Jaundice, dark urine, tender & enlarged
liver, but anicteric hepatitis is more
common
Anti HAV - antibody to HAV
IgM anti HAV - indicates recent infection,
positive result up to 4-6mos after
infection
Prevention: inactivated vaccines
Recommended for travellers to areas of
endemic disease & for high risk groups
Hepa B virus
HBV
Hepadnaviridae
Causes hepatitis B (serum hepatitis)
Envelope, cintains HBsAg, inner nucleocapsid
contains hepa B core antigen
Parenteral, sexual, vertical (perinatal)
Oncogenic
Has transverse transciptase- replicates
through intermediate RNA, resembling
Retrovirus
Findings:
Acute (<6mos)
Chronic (>6mos):
Liver cirrhosis - irreversible fibrosis
(scarring of the liver)
At high risk of developing
Hepatocellular Carcinoma
Treatment:
Acute HBV- no specific treatment
Chronic HBV- pegylated interferon alfa-2a,
entecavir, tenofovir
Prevention:
Hepa B subunit vaccine (HBsAg) given to all
newborns
Hepa B immunoglobulin (HBIG) given to all
newborns with infected mothers or w/
in 14days after sexual exposure
Contraception
Hepa C Virus
HCV
Flaviviridae but not vector borne
Causes hepatitis C (non-A,non-B hepatitis;
post transfusion hepatitis)
Parenteral
Oncogenic
Findings:
Acute:
Jaundice occurs in <25% of patients
Chronic:
Majority are chronic active hepatitis
Liver cirrhosis
End-stage liver disease due to HCV is the
most common indication for adult liver
transplants
May lead to hepatocellular carcinoma
Treatment: pegylated interferon-alfa +
rivabirin
Prevention: avoid sharing of items such as
razors, toothbrushes, nail
cutters, etc.
Hepa D Virus
HDV
Deltaviridae
A defective virus dependent on coinfection
with HBV
Delta agent - contains delta antigen (HDAg)
surrounded by an HBsAg envelope
Present HBsAg
Parenteral
Causes hepatitis D (delta hepatitis)
Acute: coinfection (with acute hepatitis B)
Chronic: superinfection (w chronic hepa B)
Findings:
Coinfection - severe acute infection,
fulminant hepatitis
Superinfection - progression to cirrhosis
HDV -causes infection only with HBV
HDAg - delta antigen, detectable in early
acute HDV infection
Anti-HD - antibody to delta Ag, indicates past
or present infection with HDV
Hepa E Virus
HEV
Hepeviridae
Fecal-oral
Causes hepatitis E (enterically transmitted)
Occurs in epidemic form
Due to contaminated water or food
Responsible for a mortality rate in excess of
20% in pregnant women
General pathological findings
Acute:
Spotty parenchymal cell degeneration with
necrosis of hepatocytes
Reticuloendothelial (kupffer) cell
hyperplasia
Preservation of reticulum franework that
allows hepatocyte to regenerate (8-12wk)
Fulminant hepatitis:
More extensive damage
Fulminant or massive
10x more common in HVB & HDV
coinfection
Chronic carriers of HBsAg
May or may not have demonstrable
evidence of liver disease
Persistent (unresolved) viral hepatitis:
Mild benign disease
Portal inflammation
Chornic active hepatitis:
Inflammation & necrosis to collapse of the
normal reticulum framework w/
bridging bw the portal triads or
terminal hepatic veins
HBsAg
General marker for infection
Presence indicates CURRENT infection,
either acute or chronic
Absence may indicate LACK of infection,
PAST infection, or IMMUNIZATION
Only antigen present in the vaccine
Anti HAV IgM positive
Acute infection with HAV
Anti-HAV IgG positive
Past infection with HAV
Anti-HCV positive
Current or past infection with HCV
Anti-HDV positive, HBsAg positive
Infection with HDV
Anti-HD positive, anti-HBc IgM positive
Coinfection with HDV & HBV
Anti HD positive, anti HBc IgM negative
Superinfection of chronic HBV
Infection with HDV
Gastroenteritis
Clinical syndrome wc includes not only diarrhea but also other symptoms like abdominal pain, nausea & vomiting
About 90% of causes of acute viral gastroenteritis are caused by either the Rotavirus or Norovirus
