Week 7 - Hepatitis Flashcards
what are 4 types of disorders of the liver
- viral hepatitis
- toxic & drug induced hepatitis
- nonalcoholic fatty liver disease
- nonalcoholic steatohepatitis
what is viral hepatitis
- inflammation of the liver due to viral infection
what are the 3 most common viral agents that cause hepatitis
- hepatitis A virus
- hepatitis B virus
- hepatitis C virus
what are 6 other causes of viral hepatitis
- hepatitis D virus
- epstein-barr virus
- cytomegalovirus
- herpes simplex
- rubella
- yellow fever
what do the viruses that cause hepatitis have the ability to cause (2)
- cause chronic infections
- be carried by a host in the absence of symptoms (= carrier)
how do viral infections cause liver cell damage (2)
- direct toxic affect on hepatocytes
- immune-mediated cell death
how is hep A transmitted
- oral-fecal route
can hep A be carried by a host in the absence of symptoms?
- no
what is the incubation period of hep A
- 2-6 weeks
how is hep B transmitted
- blood & body fluids
what is in the incubation period of hep B
- 2-3 months
can hep B cause chronic infections & carriers?
- yes
how is hep C transmitted
- blood & body fluids
what is in the incubation period of hep C
- 6-9 weeks
can hep C cause chronic infections & carriers
- yes
what are the 3 phases of hepatitis
- preicterus (prodrome) phase
- icterus (acute) phase
- posticterus (convalescent) phase
what symptoms are present during the preicterus phase of hepatitis (3)
- nonspecific signs of infection
- general GI S+S
- RUQ abdominal discomfort
what are some nonspecific signs of infection (4)
- malaise
- fatigue
- myalgia
- mild fever
what are some general GI S+S (3)
- anorexia
- NV
what symptoms are present during the icterus phase of hepatitis (4)
- enlarged liver & RUQ pain continues
- hepatic jaundice (& its S+S, pale stool, dark urine, etc.)
- coagulopathy
- encephalopathy
why do we get coagulopathy during the icterus phase of hepatitis
- due to hepatic jaundice –> impaired coagulation factor synthesis
- impaired vitamin K absorption (cholestasis)
why does encephalopathy occur during the icterus phase of hepatitis
- may or may not occur if the hepatitis is severe & causes the liver to start to fail
- when the liver can no longer produce urea = toxic levels of ammonia rise
how is the extent of liver necrosis measured?
- by testing the blood for elevation of liver-specific enzymes
what are 2 types of liver specific enzymes
- aspartate aminotransferase (AST)
- alanine aminotransferase (ALT)
what symptoms are present during the posticterus phase of hepatitis
- improvement of general signs & symptoms
- persistent abnormalities in liver function tests
see table 46-2 in joes notes for long list acute symptoms of hepatits
…
what symptoms are present in chronic hepatitis (5)
- malaise
- easy fatigability
- myalgia
- arthralgia
- hepatomegaly
who does hep A commonly effect (4)
- children
- young adults
- care givers
- travellers
where does hep A commonly occur
- daycares
- schools
how does HAV effect the liver
- multiples within & kills hepatocytes = directly toxic
how harmful in hep A
- benign & self-limiting process
- fatalities can occur
is vaccination availble for hep A
- yes
describe immunity to hep A after infection
- following recovery, IgGs persist in the blood indefinitely = immunity
what antibody is always first during infection
IgM
- list different ways hep B is transmitted (5)
- contaminated blood
- semen
- birth
- maternallu
- salivia
describe how harmful hep B is
- most people survive the intial acute hepatitis
- 1% develop fulminant liver failure = death
- 10% adults, 80% infants develop lifelong chronic hepatitis and ultimately cirrhosis
what does hep B increase the risk of
liver cancer
how is hep B treated
- interferon
- nucleosides & nucleotide analogues
what do interferons do
- interfere with viral replication (antiviral)
- and activate other cells involved in the immune system (immunomodulatory)
what are nucleoside & nucleotide analogues
- inhibit viral DNA synthesis
how is hep B prevented
- vaccination & passive immunity
how does passive immunity work
- take hep B surface antigen and give to B lymph in culture
- this tricks the lymphocytes into making antibodies for the Hep B antigen
- these antibodies are purified & infected into people
what is passive immunity good for
- people who are accutely exposed to hep B
- gives an immediate rxn where it neutralized the virus before infection
describe how hep C is transmitted
- similar to HBV but less virulent
describe how harmful hep C is
- only half of those infected develop acute hep
- but 50% of the acute phases progress to chronic hepatitis
is there a vaccination available for hep C
- no
what is treatment for hep C
- interferon (but is only useful for some)
know the charts for hep???
….
what are 4 other types of hepatitis
- D
- E
- F
- G
what is hepatitis D
- considered an incomplete virus
what is meant by “incomplete virus”
- unable to make its own surface protein
= borrows this capsule protein from HBV
describe how infection with hep D occurs
- can only occur if a person is infected with HBV
- HBV and HDV can occur simultaneously, or in a chronic hep B case
what does HDV infection frequently result in
- fulminant hepatic failure
how is HDV prevented?
- no vaccine available
- but vaccination against HBV prevents HDV in unexposed people
how do viral infections cause inflammation of the liver
- the infection triggers the immune system
- the immune cells then trigger cytotoxic killing of the infected hepatocytes = cell apoptosis = inflammation
what can hepatitis lead to
- liver damage & cirrhosis
