Section 2: Viral Hepatitis Flashcards
Hepatitis
-inflammation of the liver
-the specific cause can vary (viruses, alcohol, drugs, toxins, autoimmunity)
Hepatitis symptoms (physical)
-nausea
-abdominal pain
-fever
-malaise
-anorexia
-dark urine
-clay colored stool
-jaundice
jaundice
-yellowing of skin and whites of eyes
hepatitis with jaundice is called?
-icteric
hepatitis without jaundice is called?
-anicteric
Hepatitis lab results
-you have elevated levels of ALT, AST, Bilirubin, and PT (clotting time increased)
-can test for the presence of a variety of viruses that infect or affect the liver
hepatotropic viruses
-viruses that specifically seek out cells of the liver (tissue tropism)
-Hepatitis A, B, C, D, and E (similar names, but different viruses)
Nonhepatotropic viruses
-viruses that primarily infect other cells but can infect cells of the liver
Herpesviridae
- Epstein-Barr Virus (EBV-Mono), varicella zoster (chicken pox), cytomegalovirus (CMV)
Tropism
-cells that express specific surface receptors, which make them permissive to infection by a particular virus or bacteria
Hepatotrophic viruses are spread through?
- Fecal-oral: A and E
- Blood-borne: B, C, and D
Hepatitis A (HAV): Family, Genome, and Transmission
Family: picornaviridae
Genome: ss(+) RNA- single-stranded positive-sense RNA
-Baltimore Classification IV
Transmission: fecal-oral
Risk groups: Hepatitis A
-men who have sex with men
-International travelers
-illegal drug users
HAV Infection
-acute hepatitis after an incubation of 28 days
-does not become chronic
-people cannot be re-infected
-35% of infected are hospitalized, with only an 0.8% mortality
-high levels of virus in the stool: 2 weeks prior to symptoms and 1 week post symptoms
HAV Infection
-acute hepatitis after an incubation of 28 days
-does not become chronic
-people cannot be re-infected
-35% of infected are hospitalized, with only an 0.8% mortality
-high levels of virus in the stool: 2 weeks prior to symptoms and 1 week post symptoms
HAV Clinical testing
-Hepatitis A is a reportable infection to the state health department making an accurate detection is important
-diagnosis usually involves anti-HAV IgM
-Total anti-HAV can be used to assess immune status
List the immunoassays that exist for testing HAV
- Indirect enzyme immunoassays
- Competitive direct enzyme immunoassays
- Capture immunoassays
Hepatitis E (HEV): Family, Genome, Transmission
Family: Hepeviridae
Genome: ss(+)RNA / BC IV
Transmission: Fecal-oral
-not spread person to person or sexually
-rare in the US usually associated with travel
HEV Infection
-causes acute hepatitis 2 weeks to 2 months after infection
-40% of infected actual become ill
-does not become chronic
-1% of cases of the disease are fatal
-pregnant women infected in their third trimester have a nearly 30% mortality
-if a previous liver damage is present mortality can be up to 70% in infected people
HEV clinical testing
-rarely performed in the US
- immunoassays to detect IgM and IgG
-RT-PCR (reverse transcriptase polymerase chain reaction for detection of viral genome)
-no vaccine or treatment is currently available
Hepatitis B (HBV) : Family, Transmission, Genome
Family: hepadnaviridae
Genome: partial dsDNA/ BC VII
Transmission: blood borne/ body fluids
-1.5 cases per 100,000 US population- greatly reduced by vaccination program started in 1991
-2 billion people infected worldwide
-350 million develop chronic infection
-HBV tenth major cause of worldwide mortality
HBV Risk groups
-having sex with an infected person
-MSM
-people with multiple sex partners
- healthcare workers
- hemodialysis patients
-travelers
-IV drug users
-Newborns from infected mother
HBV virion
-enveloped virus- viral nucleocapsid surrounded by lipoprotein envelope derived from host cell
-nucleocapsid core protein: HBc/HBcAg
-envelope surface antigen: HBsAg
-structural E antigen: HBeAg
Excess HBsAg is produced and forms particles called Australian antigens
HBV Infection
-causes acute hepatitis 90 days after infection
-most people are asymptomatic
-symptoms are similar to other hepatitis infections with the addition of rash and joint pain
-40% of reported symptomatic patients need hospitalization with a mortality of 0.5-1.0
-infection can become chronic (-5%)
Chronic HBV Infection
-after acute infection is cleared virus persist
-patients can be asymptomatic for 20-30 years
-chronic infection leads to liver scarring (cirrhosis)
-hepatoma (liver cancer) results in 15-25% of chronically infected
-both cirrhosis and hepatoma can lead to death
HBV Clinical testing
-the levels of antibody are different in acute resolving patients and acute becoming chronic patients
-both antigens and antibodies are detected and have distinct clinical outcomes
HBsAg
-Anti-HBs+ (anti-HBsAg)
HBcAg
-Anti-HBc+ (anti-HBcAg)
HBeAg
-Anti-HBe+ (anti-HBeAg)
HBV treatment
-no treatment is given for acute HBV infection due to spontaneous recovery
-antivirals are given to severely ill patients but little to no evidence they work
-chronic infection with active replication is treated with interferon A, reverse transcriptase inhibitors,
-severely causes cancerous or cirrhosis can be treated with a liver transplant along with anti-HBV immunoglobulin
-five vaccines available in the US
Hepatitis D (HDV)
-also called hepatitis delta virus
-circular ssRNA (only known animal virus): only codes for two proteins (long and small delta antigens)
-required co-infection with HBV: uses HBV surface antigens to make viral envelope, and sub viral satellite
-transmission similar to HBV
-can be detected by antibody product to HDV antigens and RT-PCR
-can prevented with HBV vaccine
Hepatitis C (HCV): Family, Genome, Transmission
Family: flavivirdae
Genome: ss(+)RNA / BC IV
Transmission: blood born/ body fluids
-4 million chronically infected in the US
Risk group: Hepatitis C
-IV drug use
-Blood transfusion prior to implementation of standard testing in 1992
-sexual
HCV Infection
-70% of acutely infected patients are asymptomatic
-symptoms occur 6-7 weeks after infection
-symptomatic patients are less likely to progress to chronic infection (like HBV)
chronically infected patients
-75 to 85% develop chronic infection
- 60-70% will progress to chronic liver disease
- 5-20% will progress to liver cirrhosis or hepatoma (20 years)
Mixed essential cryoglobulinemia
-HCV infection is the most common cause of this disease (1-2%)
-immune complexes form with viruses, antibody, complement, and rheumatoid factor
-cause symptoms of type III hypersensitivity (rashes and joint pain)
-if exposed to the cold patients can develop Raynaud’s phenomena (pain, numbness, and tingling of the fingers and toes)
CV Clinical testing
-diagnosed with a group of immunoassays and molecular techniques
-immunoassays measure antibody in two different ways: screening test and confirmatory test
-molecular testing for HCV RNA are both qualitative and quantitative
-after positive molecular test, genotyping is performed because different types respond differently to treatment
-liver biopsy is performed to assess cirrhosis and hepatoma
screening test
-third generation indirect enzyme immunoassays using a mixture of viral antigens on microbeads
-measures structural and nonstructural antigens qualitatively
confirmatory test
-after a positive screen recombinant immunoblot assay (RIBA) is performed
RIBA
-similar to western blot
-uses synthetic antigens placed on nitrocellulose strip: C33c, NS5, 5-1-1, c100, and c22 peptides
-indirect immunoassay is performed with enzyme labeled secondary antibodies
HCV Treatment
-no postexposure prophylaxis is available
-no vaccine is available
-PEGylated interferon-a ribavirin is effective in 55% of patients
-patients with cirrhosis do not respond to treatment
-transplantation can be performed in liver failure `
