Viral Hepatitis Flashcards
What type of virus is hepatitis A?
An RNA virus
Explain the spread of Hep A.
Faecal to oral or via shellfish.
It is an endemic in Africa and South America, this means that a Travel history is important.
Most infections are in childhood
Incubation of Hep A.
2-6 weeks
Symptoms of Hep A.
Fever, anorexia, malaise, nausea, arthralgia
And then jaundice.
Hepatomegaly
Adenopathy
Test findings in Hep A.
ASt and ALT rise 22-40d after exposure.
ALT might be as high as >1000 IU/L.
It will then return to normal over 5-20 weeks.
IGM rises from day 25 and this indicates a recent infection.
IgG is detectable for life.
Treatment of Hep A.
Supportive
Avoid alcohol
Rarely interferon alfa for fulminant hepatitis.
Explain immunisation of hep A.
With inactivated viral protein.
1 intramuscular dose gives immunity for 1 year and then 20 years if further booster is given at 6-12 months.
Prognosis of hep A.
Usually self-limiting
Fulminant hepatitis is rare and chronicity does not occur.
What type of virus is Hep B?
HBV a DNA virus
Explain the spread of Hep B.
Blood products
IV drug users
Sexual contact
Direct contact.
It is an endemic in Far east, Africa and Mediterranean.
Incubation period of hep B.
1-6 months
(Hep A is 2-6 weeks)
Risk groups of hep B.
IV drug users and their sexual partners or carers.
Health workers
Haemophiliacs
Men who have sex with men
Haemodialysis
Sexually promiscuous
Foster carers
Close familiy members of a carrier or case
Staff or residents of institutions/prisons
Babies of HBsAg +ve mothers
Adopted child from an endemic area
Clinical features of hep B.
Similar to Hep A with Fever, malaise, anorexia, nausea arthralgia then jaundice, hepatosplenomegaly and adenopathy.
However the arthralgia and also urticaria are more common in hep B.
Test findings in hep B.
HBsAg surface antigen is present 1-6 months after exposure.
HBeAg e-antigen is present for 1.5 to 3 months after acute illness. E-antigen implies high infectivity.
Antibodies to HBcAg (anti-HBc) imply past infection.
Antibodies to HBsAg (anti-HBs) alone implies past vaccination
HBV PCR allows monitoring of response to therapy.
What does HBsAg persisting for over 6 months tell you?
This is a defining feature of carrier status.
It occurs in 5-10% of infections.
A biopsy may be indicated unless ALT is normal and HBV DNA is <2000iu/mL
Explain vaccination of hep B.
Passive immunisation may be given to non-immune contacts after high-risk exposure
Indications of hep B vaccination.
In the UK only at-risk groups are targetted.
Some other countries will vaccinate their whole population, regardless of endemicity.
Complications of hep B.
Fulminant hepatic failure
Cirrhosis
HCC
Cholangiocarcinoma
Cryoglobulinaemia
Membranous nephropathy
Polyarteritis nodosa
Treatment of hep B.
Avoid alcohol
Immunise sexual contacts
Refer all with chronic liver inflammaiton, cirrhosis or HBV DNA > 2000IU/mL for antivirals
The ai is to clear HBsAg and prevent cirrhosis and HCC.
However there is no definitive cure for Hep B, only vaccination.
What type of virus is Hep C?
RNA flavivirus
Explain the spread of Hep C.
Blood - transfusion, IV drug users, sexual contact
The UK prevalence is > 200000.
Clinical features of hep C.
Early infection is often mild/asymptomatic
Around 85% will develop silent chronic infection
Around 25% will get cirrhosis in 20 years
Of these around 4% will develop HCC/yr
Risk factors of progression of hep C.
Male
Older
Higher viral load
Use of alcohol
HIV
HBV
Test findings in Hep C.
AST:ALT ratio will be <1:1 until cirrhosis develops.
Anti-HCV antibodies confirms exposure.
HCV-PCR confirms ongoing infection/chronicity.
Liver biopsy or non-invasive elastography if HCV-PCR +ve to assess the liver damage and need for treatment.
