Hepatitis Flashcards
How is Hep A spread and what population is it seen in?
It is spread by faecal-oral or shellfish
It is endemic in Africa and s America so seen in returning travellers, most infections in children
What are the symptoms of hep a?
Incubation period 2-6 weeks
Fever, malaise, anorexia, nausea
Go on to develop jaundice, hepatosplenomegaly and adenopathy
How do IgM and IgG antibodies vary in an individual infected with hepatitis?
IgM is seen after 25 days and implies recent infection
IgG is detectable for life
What tests should be done and what will they show for hep A?
AST and ALT will rise 20-40 days after infection and return to normal 5-20 weeks
IgM will be present after 25 days showing recent infection and IgG will be present for life
How is hep A infection treated?
Supportive treatment avoid alcohol Interferon alfa (antiviral) is given in rare circumstances for fulminant hepatitis
What is fulminant hepatitis?
massive necrosis of liver parenchyma and a decrease in liver size (acute yellow atrophy) that usually occurs after infection with certain hepatitis viruses
What is the mechanism of interferon alfa?
It causes increased expression of HLA-1 molecules that increases the activation of memory cd8 t cells which increases antiviral action
How is hep A vaccinated against?
With an inactivated viral protein that gives immunity for one year unless booster given at 6-12 months which gives 20 years immunity
What is the prognosis of hep A?
Usually self limiting
How is hep B spread and what population is it seen in?
It is spread by blood to blood transfer either by sexual contact or through mixing blood e.g. IV drug users
At risk groups include: Iv drug users, health workers, haemophiliacs (impaired clotting), MSM, haemodialysis, sexually promiscuous
What are the signs of hep B?
Resembles hep A but urticarial is commoner
What is the incubation period of hep B?
1-6 months
What is HBsAg? how long is it present for?
It is hep b surface antigen and is present 1-6 months after infection
What is HBeAg? how long is it present for?
This is hep B e antigen and it is present 1-3 months after infection
This implies high infectivity
What does hep B surface antigen being present after 6 months imply?
This means that the individual has carrier status and occurs in 5-10% of people
biopsy may be indicated
What do antibodies to HBc (core) imply?
That there has been some past infection
What do antibodies to HBsAg alone imply?
Vaccination
How is Hep B treated?
Refer for antivirals (interferon alfa-2a or long term but better tolerated nucleotide analogues e.g. tenofevir)
Avoid alcohol
Aim to clear HBsAg and prevent cirrhosis
hepatocellular carcinoma risk is greatly increased if HBsAg positive
How is hep C spread and what population is it seen in?
Spread by blood and seen in similar population as hep B
What are the signs and symptoms of hep C?
Asymptomatic often
85% get silent asymptomatic infection
25% get cirrhosis
What tests are done for hep C?
LFTs, anti-HPV antibodies shows exposure
PCR confirms ongoing infection
Liver biopsy to assess need for treatment
Determine HCV genetype for treatment
How is hep C treated?
Now considered almost curable due to good antivirals
e.g. ledipasvir
How does hep D often get transmitted?
5% of hep B carriers also have hep D
How is hep D treated?
Interferon alfa doesn’t work very well so often liver transplant
Which other hepatitis is hep E similar to?
Hep A, has no specific treatment
What is the cause of autoimmune hepatitis?
Unknown cause with abnormal t cell function and autoantibodies against hepatocyte surface antigens
How does autoimmune hepatitis present?
It typically presents in young or middle aged women and has the signs of acute hepatitis (fever malaise etc.)
Can also present with gradual jaundice or asymptomatic
