Viral Hepatitis Flashcards
What is the definition of acute and chronic hepatitis
A
Acute - Usually symptomatic with deranged LFTs (raised ALT and AST)
Chronic - When hepatitis virus presents for more than 6 months. Usually is asymptomatic
What are the routes of transmission for the different hepatitis viruses
A and E - Faecal oral route
B, C and D - Blood borne
What are the infectious and non infectious causes of acute hepatitis?
Infectious - Hepatitis viruses, EBV, CMV, toxoplasmosis, leptospirosis, Q fever, syphilis, malaria.
Non infectious m- Toxins, drugs, alcohol, autoimmune, Wilsons and haemochromatosis
What are the different laboratory diagnostic techniques for viral hepatitis?
Direct detection of the immune response via IgM or IgG.
Viral nucleic acid detection (RNA or DNA) or antigen detection (HBV and HCV)
What are the features of Hepatitis A?
RNA virus transmitted via faeco-oral route.
Incubation period is 2-4 weeks.
NO chronic carriage.
Age is the main determinant of severity. Most children are asymptomatic.
Self limiting illness with no treatments however good immunity after infection/vaccination
Explain the diagnosis of hepatitis A
In an acute infection patient will be IgM positive or have HAV RNA in blood/stool.
IN a previous hep A/vaccinated patient IgG will be detected
** IgM and/or IgG against Hepatitis A virus (HAV)
Describe features of the hepatitis A vaccine
Inactivated virus which gives life long immunity after 2 doeses. Given to travellers, MSM, IVDU or chronic liver diseases.
When is hepatitis A immune globulin used?
f patient is vaccine allergic or if there is less than 4 weeks till travel. It offers 3-6 months of immunity. It is pooled immunoglobulin
Describe features of hepatitis E
RNA virus transmission occurs via faeco-oral route or contaminated pork products. Incubation period is 40days. 4 genotypes with most common being GT3 (genotype 3).
Treatment is supportive, no vaccine and chronic hep E only in immunocompromised High mortality in pregnancy
What are the symptoms of Viral hepatitis?
- Flu like prodrome,
- RUQ pain,
- Tender hepatomegaly,
- Jaundice,
- Derranged LFTs
- Malaise and fatigue,
- Diarrhoea,
What are the complications of a Hepatitis E infection?
Neurological complications which are associated with genotype 3. These include:
- Guilliane barre syndrome,
- Encephalitis,
- Ataxia,
- Myopathy
Describe features of hepatitis B and its routes of transmission
DNA virus which causes around 2million deaths per year. Most common viral hep. However is vaccine preventable.
Transmission occurs via - Mother to baby (most common), contaminated needles/syringes, child to child, organs and tissue transplants, bodily fluids or transfusion of blood products.
Describe features of acute hepatitis B infections
Incubation is 2-6months.
Age at time of infection determines severity and risk of developing chronic hepatitis B. Infection at young age is likely to be asymptomatic but high risk of chronic. Infection at old age is likely to be symptomatic but not chronic
What are the complications of a hepatitis B infection
Chronic HBV which can cause:
- Cirrhosis,
- Decompensation,
- Hepatocellular carcinoma (can present with weight loss, abdo pain, fever, cachexia, bloody ascites, jaundice),
- Death
What are the laboratory tests in hepatitis B?
sAg (surface antigen) - marker of active infection.
sAb (Surface antibody) - marker of immunity.
cAb (core antibody) - present in anyone who has had active infection, negative in vaccination.
eAg (e antigen) suggests high infectivity.
eAb (e antibody) suggests low infectivity.