Chapter 43- Viral hepatitis Flashcards
what is hepatitis
a clinical syndrome characterized by inflammation of the liver
what causes jaundice in hepatitis
hepatocyte death releases bilirubin
what is bilirubin
a biproduct of heme metabolism in the liver
what are the causes of hepatitis
-viral: hepatitis viruses A-E, herpes viruses (HSV,EBV,CMV), adenovirus, yellow fever virus
- alcohol
- toxins
where do hepatitis viruses replicate and why
in the hepatocyte because they have a strong tropism for the liver
85% of liver cells are _____
hepatocytes
what is infectious hepatitis also known as, what, letters is it, and what causes it
- “hit and run”
- A and E
- fecal- oral
what is serum hepatitis also known as, what letters is it and what causes it
- “hide and infiltrate”
- B, C and D
- blood and sexual fluid
what is the nucleic acid composition and virus family of Hepatitis A
- linear and ssRNA
- picornaviridae
describe hepatitis A and what causes it
- infectious hepatitis
- HAV: isocahedral, naked capsid virus, positive strand linear RNA
- spread by fecal- oral contamination of food, drink or shellfish
what is HAV shed into and what does it directly kill
- shed into bile ducts and into intestine and passes out of the body in the feces
- HAV directly kills hepatocytes
what are the clinical manifestations of hepatitis A
- mild intestinal infection
- viremia occurs occasionally, leading to liver infection and jaundice
what is the treatment, prevention and control of hepatitis A
- killed HAV vaccine
- post exposure immune globulin
which adults are more likely to display symptoms of hepatitis A
adults from nonendemic regions
how big is the genome of hepatitis B
- smallest genome
- 3200 nucleotides
what is the nucleic acid composition and virus family of Hepatitis B
- nicked circular
- mostly dsDNA
- hepadnaviridae
- enveloped
what are the 3 distinct particles of hepatitis B
- 22nm particle
- variable tubular/ filamentous particle (22nm diameter)
- 42nm Dane particle (infective form of virus)
what is the main component of the envelope in hepatitis B and where is it located
- embedded in lipid bilayer
- HBsAg-S is main component
HBeAg is processed form of the core:
HBcAg
what is HBeAg mostly secreted from and where is it found
infected cells and found in the blood stream
what is a useful marker for HBV infection
HBeAg
filaments are enriched for ______
HBsAg-L
describe both types of 22nm particles
-empty envelopes
- spherical
- up to 10^13 particles per mL
When does RT occur in hepatitis B
during viral assembly
what is reverse transcription done by in hepatitis B
viral reverse transcriptase
what is transcription done by in hepatitis B
host RNA polymerase
how is priming of reverse transcription done
by TP (terminal protein domain) of viral polymerase by adding first nucleotide to a tyrosine residue of TP
what determines the course of HBV infection
CMI
what do CTLs kill in HBV infection
infected hepatocytes
what are the ouctomes of acute HBV infection
- 90% resolution
- 9% HBsAg+ for greater than 6 months
- 1% fulminant hepatitis
- HBsAg+ causes resolution or chronic active hepatitis
- chronic active hepatitis causes cirrhosis or hepatic cell carcinoma
what percentage of infants infected with HBV become chronically infected and why
90% because of immature cell mediated immune response
what causes hepatocellular carcinoma
- increased cell division due to regeneration increases chances of mutation
-peroxides and free radicals from CTL killing
how does HBV kill hepaocytes
-indirectly
- CTLs directed against MHC class I proteins bound to viral antigens on hepatocyte surface
- cytokine release promotes inflammation and tissue damage
what would you be positive for if prior vaccination for hepatitis B
- Anti HBs
what would you be positive for if prior acute infection, resolved
-Anti HBe
- Anti- HBc
- Anti HBs
what would you be positive for if acute or chronic hepatitis B infection
- HBeAg
- Anti HBc
- HbsAg
what would you be positive for if you had later stage in chronic infection of hepatitis B
- HbsAg
- Anti- HBc
- Anti- Hbe
what is the treatment, prevention and control for hepatitis B
- vaccination recommended for all infants in USA
- HBsAg particles produced in yeast
- passive immunotherapy within 7 days of exposure
- reverse transcriptase inhibitors
what is the nucleic acid composition and virus family of hepatitis D
- circular ssRNA
- deltaviridae
what does hepatitis D virus depend on to replicate
HBV virus
what is a chronic HBV infection exacerbated by
infection with hepatitis delta virus
what is the nucleic acid composition and virus family of hepatitis C
- linear and ssRNA
- flaviviridae
what is a chronic HBV infection exacerbated by
infection with hepatitis delta virus
describe hepatitis C and how it is transferred to others
- enveloped
- blood and sexual fluid, mother to fetus, fecal- oral route, and organ transplants
how does HCV kill hepatocytes
-indirectly
- CTLs directed against MHC class I proteins bound to viral antigens on hepatocyte surface
- cytokine release promotes inflammation and tissue damage
what are the outcomes of hepatitis C virus acute infections
- 15% recovery and clearance
- 15% cirrhosis rapid onset
- 70% persistent infection
what are the outcomes of chronic hepatitis
- 20% cirrhosis
- 6% liver failure
- 4% hepatocellular carcinoma
what is mixed cryoglobulinemia
-immune complex disease of kidney and other sites
- disease outside of liver
- inflammation and blockage of small and medium blood vessels caused by cryoglobulin deposition
what is the nucleic acid composition and virus family of hepatitis E
- linear and ssRNA
- calciviridae
describe hepatitis E and how its spread
- not budding, released as naked capsid virus
- spread in contaminated food and drink, human to human and animal to human (common source = pigs)
