Hepatitis Flashcards
what is most common cause of Hepatits A?
contaminated water and food and intimate sexual contacts
- blood and stool infectious during 2-6 week incubation period
- transmitted via oral-fecal route and rarely parenterally
What is a common cause of Hep B?
=blood and blood products
- sexual activity
- mother-fetus
- blood borne DNA virus present in serum, saliva, semen and vaginal secretions
Cause of Hep C?
Blood borne RNA virus in which source of infection uncertain
-a/w blood transfusion, IV drug use
What is diagnostic for acute Hep A?
Anti-HAV (antibody to hep A) and IgM (antibody to HAV which implies recent infection) peak within 3-6 months.
What does HAV IgG test detect?
IgG detects IgG antibodies that develop later in the course of the dz. IgG antibodies remain present for many years, usually for life, providing protection against recurrent infection by the same virus. The IgG test is used to detect past HAV infections and may occasionally be used to determine if an individual has developed immunity from a previous infection (immune status), in which case a vaccine is not necessary.
What does HAV IgM antibody test?
The HAV IgM antibody test detects the first antibody produced by the body when it is exposed to hepatitis A. This test is used to detect early or recent infections and to diagnose the disease in people with symptoms of acute hepatitis. It may be performed as part of an acute viral hepatitis panel.
what does the total HAV antibody test detect?
IgM and IgG antibodies and thus may be used to identify both current and past infections. This test will also be positive after receiving the vaccine, so sometimes it may be used to determine whether a person has developed immunity after vaccination, though this practice is not advised. Recommendations of the Advisory Committee on Immunization Practices (ACIP) state that “post-vaccination testing is not indicated because of the high rate of vaccine response among adults and children. In addition, not all testing methods approved for routine diagnostic use in the United States have the sensitivity to detect low anti-HAV concentrations after vaccination.”
when is the presence of IgM antibodies to Hep A ordered?
when someone has acute symptoms such as:
Fever Fatigue Loss of appetite Nausea, vomiting, abdominal pain Dark urine and/or pale colored stool Joint pain Jaundice
HAV IgM positive then…
Acute or recent infection
HAV IgM negative. Total antibody (IgM and IgG) positive?
no active infection but has previous exposure, has developed immunity to HAV or recently vaccinated
Hav IgM not performed but positive HAV IgG or total antibody (IgM and IgG) positive
Has been exposed to HAV but does not r/o active infection
HAV IgM not performed HAV IgG or total Antibody (IgM and IgG) negative
no current or previous HAV infection. Vaccine may be warranted
Serology for active Hep A
Anti-HAV and IgM (think immediate)
Serology for recovered Hep A
Anti-HAV, IgG (gone)
What does Hep B surface antigen (HBsAG) mean?
First evidence of HBV infection. Will remain positive in asymptomatic carriers and chronic hep B patients
