Hepatitis Viruses Flashcards
how many known hepatitis viruses are there?
6–not phlyogenically related
what do all hepatitis viruses have in common?
they all primarily affect hepatocytes and cause hepatitis on first infection
what should you do before doing a virology work up for hepatitis?
rule out pharmaceutical causes of hepatitis
what virus is Hep A caused by and how is it classified?
picornavirus. ssRNA with naked icosahedral capsid
can Hep A recur?
no
how is Hep A transmitted and what is the major cause of its symptoms?
fecal-oral and hepatitis is mostly immunogenic
what is the most likely scenario for Hep A contraction?
subclinical infection
what is a rare cause of mortality in Hep A patients?
fulminant hepatitis
what are the symptoms caused by Hep A?
fever, jaundice, gastroenteritis, dark unine and pale feces
what historical features of Hep A are relevant?
vaccination, foreign travel, daycare and shellfish consumption
what lab tests are available for Hep A?
serology (differentiate between acute and resolved with IgM vs IgG) and serum ALT (liver damage)
how do you treat Hep A?
fluids and monitoring while discontinuing other liver strains (alcohol and medications)
how is Hep A prevented?
vaccine and Ig prophylaxis
what virus is Hep B caused by and how is it classified?
hepadnavirus: small enveloped DNA virus (partially double stranded)
what viral particles are found in serum of a HBV infected person?
virions and incomplete decoys
a patient cannot be infected twice with hepatitis B. True or false?
true
what does replication of HBV leave behind in the cell?
integrated viral DNA
how is HBV transmitted?
blood, sex and birthing
what is the most common course of HBV and what is the alternative?
most people have acute hepatitis and then clear the virus but some have a chronic infection (10%)
what are some possible outcomes of chronic HBV?
cirrhosis (immunogenic), kidney damage and arthritis (accumulation of immune complexes) and hepatic cell carcinoma (integrated viral DNA)
what laboratory tests are available for HBV?
serology (to test clearance), serum ALT and optional PCR and biopsy
how should acute HBV be treated?
supportive care
How should chronic HBV be treated?
if there is damaging infection, can treat with polymerase inhibitors and pegylated interferon
how can HBV be prevented
vaccineation and Ig prophylaxis
why does liver transplant fail with HBV carriers?
new liver cells will become infected with virions outside of the liver
what virus is Hep C caused by and how is it classified?
flavivirus, enveloped +ssRNA
what are two major differences between Hep B and Hep C?
there is no vaccine for HCV and there is a much higher potential for chronic infection (85%)
how is HCV transmitted?
by blood and less efficiently by sex
what is the treatment for acute HCV?
pegylated interferon to reduce risk of chronic infection
what is the treatment for chronic HCV?
combined therapy to achive sustained viral response: ribavirin, protease inhibitors and pegylated interferon
what determines the length of treatment for HCV?
the serotype
types 2 and 3 have >50% recovery with 6 months
types 1 and 4 have <50% recovery with 1-2 years
what should be monitored during HCV treatment?
liver function, kidney function and blood and viral RNA levels
why do many HCV patients discontinue treatment or reduce their dose?
interferon has many bad side effects
what should be considered if HCV treatment fails?
living donor liver transplant
why are living donor transplants usually more successful than cadaver transplants?
they can be scheduled so the patient can be treated with a short hard course of interferon to clear extra hepatic virus reservoirs
what are some complications of chronic HCV?
liver failure, cirrhosis, hepatocellular carcinoma and death
what laboratory tests are available for HCV?
diagnosa by EIA and genotype with RIBA
judge severity of disease by liver biopsy
