Viral hepatitis Flashcards
what are the different types of hepatitis viruses?
= Hepatitis A-E
what is the chief or sole clinical manifestation of hepatitis virus?
= liver disease
how is hepatitis A transmitted?
= faecal-oral spread
- poor hygiene/overcrowding
- gay men and IV drug users
describe the clinical aspects of hepatitis A?
- acute hepatitis, no chronic infection
- peak incidence of symptomatic disease in older children/young adults
how would you confirm hepatitis A?
- clotted blood for serology (gold top vacutainer)
= same sample for all causes of viral hepatitis
= hepatitis A IgM
how would you control the spread of hepatitis A?
= hygiene
= vaccine prophylaxis
where is hepatitis E common?
= in tropics
- evidence of chronic infections in pigs, deer and rabbits.
- severe disease in pregnant women
describe the clinical and transmission specs of hepatitis E?
= clinically like Hep A
transmission
= faecal-oral transmission
Who is at risk of getting a chronic hepatitis E infection?
= immunocompromised humans
when is hepatitis D ONLY found with?
= with hepatitis B
describe hepatitis D?
= parasite of a parasite
- exacerbates hepatitis B infections
- co-infections or superinfection
= rare in scotland
how is hepatitis B transmitted?
= sex
= mother to child
= blood
= chronic infections more likely to result if first exposure is in childhood
whoa are at higher risk for developing hepatitis B?
- people born in areas of intermediate/high prevalence
- mutual sexual partners
- people who inject drugs
- children of infected muscles
how would you confirm hepatitis B?
- hepatitis B surface antigen (HBsAg) present in blood of all infections individuals
= present for more than 6 months in chronic infections
= Hep B e antigen usually present in highly infectious individuals
= Hep B virus DNA always also present in high amounts in highly infected individuals
= Hep B DNA TESTS used to predict risk of chronic liver disease and monitor therapy - hep B IgM
= most likely to be present in recently infected vases - anti-has present in immunity
how would you control hepatitis B?
- minimise exposure to; = safe blood = safe sex = needle exchange = prevention of needle sticks = screening of pregnant women
- 2 pre-exposure vaccines
- posit-exposure pro-phylaxis
= vaccine
= Hyperimmune Hep B immunoglobulin
how is hepatitis C transmitted?
= similar to hep B
- no vaccine available
True or false.
Infection with hepatitis C results in chronic infection in about 75% of cases.
True
what defines chronic infection ?
= 6 months of infection
describe what happens once chronic infection of hepatits B and C has been acquired?
Hep B
= spontaneous cure not uncommon, even after many years of infection
Hep C
= once chronic infection established, spontaneous cure is NOT SEEN
describe how you would diagnose Hep C?
= patient at risk of Hep C, or with signs of chronic liver disease = test for antibody to hep C virus = Negative NOT INFECTED OR = Positive PAST OR ACTIVE INFECTION = Test for Hep C virus RNA by PCR - negative = past infection - positive = active infection
describe hep C virus control?
= no vaccine
= minimise exposure
how do you manage acute viral hepatitis?
= symptomatic = no anti-virals given = monitor for encephalopathy = monitor for resolution = immunisation contacts = tests for other infections if at risk = vaccine against her infections if at risk
how do you manage chronic viral hepatitis?
1) Antivirals
2) Vaccination
- other hepatitis viruses
- if cirrhotic: influenza, pneumococcal
3) Infection control
4) Alcohol↓
5) Hepatocellular carcinoma awareness/screening
- most important for patients with cirrhosis
- serum -alpha fetoprotein (AFP) and ultrasonography
what people should get anti-virals?
- Chronic infection
= HCV RNA present and genotype known
= HBsAg and Hep B DNA present - Risk of complications
= evidence of inflammation / fibrosis sought, especially in Hep B
= non-invasive tests of fibrosis - Fit for treatment
= cirrhosis more difficult to treat, but cirrhotic patients are treated as a priority
= liver cancer at presentation is a contraindication
= HIV co-infection more difficult to trea - Patient may have other priorities
what is interferon alfa?
= human protein
- part of immune response to viral infection
- made by genetic engineering
- given by injection as pegylated interferon
what are side effects of interferon alfa?
minor = flue like symptoms - chills - sore muscle - malaise
major
= auto-immune disease
= psychosis
- thyroid disease
what is an adverse affect of the anti-viral ribavirin?
= anaemia
how do you treat chronic hep B?
OPTION 1 = Suppressive antiviral drug (5 licensed to date) e.g. entecavir, tenofovir \+ safer \+ increasing range available - suppression not cure - resistance can develop
OPTION 2 = Peginterferon alone \+ sustained cure possible from a few months of therapy - side effects - injections - only minority gain benefit
Try in HBsAg and HBeAg pos patients with compensated disease and prediction of good chance of cure
what are the aims of chronic hep B therapy?
- reduction inf HBV DNA (suppression)
- loss of HBeAg (enduring suppression)
- loss of HBsAg (cure)
= improve liver and histopathology
= reduced infectivity
= reduced progression to cirrhosis and primary hepato-cellular carcinomas
= reduced mortality
what are the aims/benefits of chronic hep C therapy?
= Response defined by loss of HCV RNA in blood sustained to 6 months after end of therapy
- virological cure (Sustained Virological Response or SVR)
- relapse after SVR is rare
- reinfection can occur
After SVR patients have: = improved liver biochemistry = improved histopathology = reduced infectivity = reduced incidence of primary liver cancer = reduced mortality
what are the principles of HCV therapy?
Choice of anti-viral regime based on; = genotype virus = genotype of patients interferon response genes = stage of disease = past treatment experience = likelihood of side-effects
give examples of current anti-virals?
= Simeprevir, Ledipasvir, Daclatasvir, Ombitasvir, Paritaprevir, Elbasvir, Grazoprevir
- Used in certain genotypes in combinations of 2 or 3 drugs
- Safe and well tolerated
= Sofosbuvir, Voxilaprevir, Velpatasvir
- Active against all genotypes, used in combination
- Safe and well tolerated
= Classes of HCV antiviral are called NS3-NS4A, NS5A and NS5B inhibitors depending on mode of action
Standard is now all oral, interferon free courses of 2 or 3 antivirals for up to 12 weeks with high Sustained Virological Responses
