Mind Map Gallery Hepatitis
- 518
- 2
Hepatitis
A mind map about hepatitis.
Edited at 2020-09-08 01:18:24
- Recommended to you
- Outline
Hepatitis
General
acute
systemic symptoms
fatigue, fever, aches, cough, runny nose, sore throat
jaundice
high AST & ALT, GGT & alkaline phosphatase
painful, enlarged liver
chronic
often asymptomatic
may have enlarged liver, mildly elevated liver function enzymes
Hep A
clinical features
~30 day incubation
usually causes jaundice, especially in adolescents & adults
not chronic
highest death rate in 50+
epidemiology
cases occur in community-wide outbreaks
highest in S. America, Africa, Asia
transmission
fecal-oral
close personal contact
contaminated food or water
natural history
1-2 months: symptoms & high TA
first IgM anti-HAV
then long-term total anti-HAV
Subtopic 4
vaccine
all children starting at age 1
also used to control community outbreaks
prevaccination testing
consider cost and prevalence
good for older adults, adults who lived in endemic areas
impact has greatly reduced incidence
combo diseases
increased risk of acute liver failure & death with HAV, HBV, CLD
complications
acute liver failure
cholestatic hepatitis
jaundice with bile stasis in inflamed intrahepatic bile ducts
relapsing hepatitis
Hep B
clinical features
60-90 day incubation
only Hep that is a DNA virus
jaundice only 30-50% in 5+ yo
acute rarely fatal
may lead to chronic infection, especially in those <5 yo
immature immune response does not rid virus and results in chronic infection
diagnosis
HBsAg
surface Ag
indicates disease present (acute or chronic)
if anti-HBs present, then pt is immune (vaccine or recovery)
HBcAg
core Ag
anti-HBc forms early and stays (although IgM decreases)
HBV DNA
directly detects infection
epidemiology
worldwide chronic
risk factors include IV drug, gay men, multiple partners
transmission
highly infectious
present at high conc in blood, serum, and wound exudates
parenteral
sexual transmission is common
natural history
acute infection
acute hepatitis and recovery
chronic infection
acute liver failure, death
chronic infection
inactive carrier state
chronic hepatitis, cirrhosis, HCC
vaccine
all children
adults at high risk
HD pts, healthcare workers, sexually active, etc
treatment
interferon alfa, nucleoside analogs
reduce progression, cancer; or prevent virus before transplant
Hep C
general characteristics
ss RNA virus
encodes 11 proteins as a polyprotein
flavivirus
proteins
NS3
cleaves polyprotein translated from RNA
cleaves adapter proteins
inhibits initial IFN response
NS5b
RNA-dep RNA pol
epidemiology
high prevalence worldwide and in US
high prevalence of chronic disease
risk factors
IV drug use
blood product/transplant before testing
long-term HD
sex w/multiple partners
natural history
85% leads to chronic infection
chronic HCV may lead to cirrhosis, then:
end-stage liver disease
HCC
liver transplant
clinical manifestations
frequently no Sx until advanced liver disease
malaise, weakness, anorexia
screening/lab tests
indicated for:
any IV or snorting drug users
clotting factor or HD pts
high ALT levels
USPSTF: screening not recommended
serologic or molecular assays
treatment
interferon
indicated for:
persistent high ALT
detectable HCV
liver fibrosis or inflammation
no active autoimmune disease
no decompensation/liver failure
not pregnant
no current drug use
Immune response
viral immune evasion
via NS3 & decr IFN production
via NS5A interfering with antiviral gene expression
CD8 T cells
persistant infection
not enough immune response
CD4 T cells falter (?suppression)
CD8 T cells then fail
epitope mutations
epitopes no longer recognized by MHC-I
become dysfunction (anergic)
no CD4 help
suppressive cytokines (IL-10, etc)
Tregs
natural Ab DON'T prevent reinfection
but immunity leads to more rapid resolution
vaccine?
would induce both Ab response AND memory T cell response
Hep D
co-infection or super-infection with Hep B
Hep E
general characteristics
RNA virus
waterborne outbreaks
fecal-oral transmission
endemic in developing world
clinical
highest incidence in young adults
high fatality in pregnant women
vaccine available
Viral Immune Defenses
Immune responses
virus-infected cells express MIC ligands
CD8 T cells recognize
kill cell
incr ALT/AST
hepatitis
secrete cytokines
IFN-gamma
TNF
IL-2
RIG-I, TLR
IRF3 (a TF)
IFN-beta
autocrine
IRF7
IFN-alpha
IFN response
reistance to viral replication
incr expression: receptors on NK cell
activate NK cells to kill virus-infected cells
paracrine
Liver
bacteria & viruses enter from intestines
Kupffer cells & other APC's
bacteria (normal, lots)
NOD & TLR signalling
NFK-B
IL-10 (suppression)
dampens immune response
virus particles (not normal)
IRF3
IFN-alpha & beta
increase immune response