14 - Hepatitis Flashcards
What are the main causes of acute viral hepatitis in the USA (as of 2013)? What about Chronic?
Acute: Hep C most, then Hep B, smallest amount of Hep A.
Chronic: HepC most chronic in the US followed by HepB (in other places HepB is more chronic). HepA is not chronic.
What type of virus causes HepA? How many serotypes are there, and how is it spread?
RNA picornavirus.
Single serotype, only infects human.
Fecal-oral; spread through contaminated food, water, raw shellfish, and poor hygiene. Most commonly by food handlers, daycare workers, and children.
What is the incubation period of HepA? What does the virus cause?
~4 wks (2-6 wk range).
Acute disease and asymptomatic disease.
Symptomatic causes jaundice: 70-8-% adults and 10% children (these percentages are true for all symptoms of Hep)
What is the fatality associated with HepA? Can it become chronic? What is the immunity?
Fatality: overall 0.3%, >50 years: 1.8%
No chronicity, so you will never find it in a person for more than 6 mo (although it may kill you in that six months - rarely)
Protective Ab develop in response to infection confers lifelong immunity (if you survive the 6 mo, you are immune forever)
What occurs when HepA enters the body?
Enters via oral acquisition, crosses the intestines to enter the blood.
Some is released into stool.
What body fluids have the highest concentration of HepA virus?
Feces (because its fecal-oral), then serum, then saliva.
Urine does NOT have any.
What are the most common sources of HepA virus in the US?
- Personal contact
- Day care center
- Foreign travel
- Drug use
- Outbreak
What are clinical symptoms of viral hepatitis A?
Fever Fatigue Nausea Loss of appetitite Abd. pain - RUQ (liver) Dark urine (bilirubinuria-bilirubin leaking into the urine) Jaundice (seen in eyes first)
Not many symptoms in children.
Describe the time it takes for HAV-specific immunoglobulins to appear after ingestion of virus?
- virus in feces (but we never look for virus in feces the clinical setting)
- HAV-IgM: tells you you have acute HepA
- HAV-IgG: means you were exposed and recovered and are now immune or you were vaccinated
How do you diagnose HepA? What does each tell you?
HepA Ab
HepA IgM = acute (<6 mo) ie you currently have it
HepA IgG = previous exposure (>6 months) and now immune or vaccinated ie you no longer have it
-protective antibody
Who should get the HepA vaccine? When should they get it?
All children at age 1, people working in or traveling to areas with high incidence (mexico), people with chronic liver disease(alcoholic cirrhosis), or working with HAV.
To doses, six months apart.
If you don’t have time for the 2 shots 6 months apart, how do you prevent HepA pre-exposure? What about post exposure?
Pre-exposure: immune globulin to travelers to int-high HAV endemic regions.
Post exposure (within 14 days): immune globulin routine to do household and intimate contact.
What type of virus is Hep E? What is the incubation time and how is it spread?
RNA calicivirus.
Fecal-oral, contamination drinking water, minimal person-person, recent travel to endemic area.
Over 40 day incubation.
E is very similar to A.
What is the case fatality of HepE? Can it become chronic? Where is it most common geographically?
Overall: 1-3%
Pregnant women: 15-45% - pregnant women have a MUCH HIGHER risk of mortality with HepE than A
No chronicity
Central America, north Africa, middle east, and china.
What is the typical serological course of hep E?
Some virus will be seen in stool first
ALT is the most common to go up in the serum with a HepE infection.
IgG anti-HEV and IgM anti-HEV are present as well
There is no vaccine so if someone has IgG that means that they’ve had the disease
How would you diagnose hep E?
Hep E Ab
Hep E IgM = acute (<6 mo)
Hep E IgG = previous exposure (>6 mo) and now immune
-protective Ab (this is in contrast to HIV where having the protective antibody does NOT mean you’re protected)
What type of virus is HepB? What are some examples? What are the different genotypes? What genotype is most associated with cancer?
DNA Hepadnavirus.
Woodchucks, ground squirrel, duck hepatitis virus (remember HepA and HepE were not found in animals)
Genotypes A-H: C is the one most associated with cancer
What is the structure of Hep B?
It’s mostly dsDNA
Dane particles are found in serum: made of hepB antigen only, there’s no DNA
Describe how Hep B viral particles infect a cell and spread? What happens in this process if you’re immunized?
If you are immunized the virus
can’t attach to the liver.
- after attaching it uncoats
- enters nucleus
- mRNA completed
- goes into cytoplasm
- reverse transcription occurs
- then you make a DNA template and it is coated
- Then the active virus is released (sometimes the coating material is released on its own – this is what is given with antibodies (remember it doesn’t have theDNA so can’t infect).
What are the four ways that HepB is transmitted?
Four ways to transmit the virus:
1. BLOOD PRODUCTS
- Sexual transmission (high in MSM community)
- Horizontal transmission: person to person by sharing needles or blood transfusion or sex
- Vertical transmission: Mom is positive for chronic HepB and passes it off to the newborn