Session 8: Blood Borne Viruses - Viral Hepatitis Flashcards
Definition of hepatitis.
Inflammation of liver.
Where does hepatitis viruses replicate?
In the hepatocytes (hepatotropic) Destroys hepatocytes as well.
Label the diagram.
Explain the production and excretion of bilirubin.
RBCs -> Haemoglobin -> Biliverdin -> Bilirubin (into blood stream) -> Bilirubin albumin -> (into liver) -> Bilirubin conjugated into conjugated bilirubin then either excreted into urine or sent as bile into small intestine where it becomes urobilinogen. Urobilinogen can then either enter enterohepatic circulation and go back to liver, or it can become urobilin stercobilin and be excreted in feces.
Give types of jaundice. Give cause as well.
Where do they take place?
Prehepatic takes place outside of the liver in reticuloendothelial system due to haemolysis.
Cholestatic (two subgroups):
Intrahepatic and Extrahepatic
Intrahepatic is in the liver
Extrahepatic is somewhere in the bile duct.
Causes of intrahepatic jaundice.
Viral hepatitis
Drugs
Alcoholic hepatitis
Cirrhosis
Autoimmune cholangitis
Pregnancy
Causes of extrahepatic jaundice.
Any obstruction of bile:
Common duct stones
Carcinoma
Biliary stricture
Sclerosin cholangitis
Pancreatitic pseudocyst
Give liver function tests.
Bilirubin
Liver transaminases (ALT, AST)
Alkaline phosphatase (ALP)
Albumin
Tests of coagulation like clotting factors, INR and PT.
If a blood test comes back with elevated Bilirubin and ALT but normal ALP and normal Hb. What does that suggest?
Reduced liver function.
No damage to biliary tract (ALP).
No haemolysis (Hb)
Intra-hepatic jaundice
Transmission of Hep B. Who’s at risk?
Vertical transmission most common (75% of cases)
Sexual contact
People who inject drugs
Close household contacts
Significant blood exposure
HCW via needlestick injuries
Symptoms of Acute Hep B.
Can vary and also be asymptomatic however:
Jaundice
Fatigue
Abdo pain
Anorexia/Nausea/Vomiting
Arthralgia
Prevalence of Hep B becoming chronic.
<10% of infected as adults
90% if infected in infancy in Asia/China
Serology of Hep B.
HBsAg (Surface antigen) will rise withing 6/52 causing rise in ALT and DNA.
This is followed by e-antigen which is highly infectious.
Followed by core antibody (IgM) which is the first antibody to appear.
Followed by e-antibody which heralds disapperance of e-antigen and lowers infectivity.
Surface antibody appears which is the last antibody to appear and clears virus and starts recovery.
Core antibody (IgG) persists for life.
HBV DNA PCR is used to test.
Definition of chronic Hep B.
Persistence of HBsAg after 6 months (surface antigen).
25% chronic infections leads to cirrhosis and 5% will develop hepatocellular carcinoma.
Treatment of hep B
No cure so life-long anti-virals to suppress viral replication may be needed. It is however not required for everyone.
How do you prevent Hep B?
By vaccination.
Genetically engineered surface antigen.
3 doses + boosters if required
Effective in most people
Produces surface antibody response.
>10 adequate
>100 long term protection
Complete the table
Transmission of Hepatitis C. Who is at risk?
People who inject drugs i.e. IV drug users.
IV heroin, crack and meth
Also crack or heroin smokers.
Sexual contact is below 1% but high if HIV co-infected
Perinatal is below 5%
Blood transfusions prior to 1991
Needlestick injuries
Once contracted Hep C how many will be chronically infected?
80%
Complications of chronic Hepatitis C infection.
Decompensated liver disease
Hepatocellular carcinoma
Needing liver transplant
All this from chronic liver disease/cirrhosis
Symptoms of hepatitis C (acute or chronic)
80% have no symptoms
20% get fatigue, anorexia, nausea and abdo pain in right upper quadrant.
Blood tests for hepatitis C.
Seroloy - anti-Hep C antibody only however this will not tell you if you have the infection or if you have been cured.
The anti-Hep C antibodies are no protective like in Hep-B meaning you can get re-infected.
Viral PCR is needed to confirm diagnosis. If this is positive you can confirm an on-going or chronic Hep C infection.
Treatment of Hep C.
Directly acting antiviral drug combo
8-12 weeks with a over a 90% chance of cure however it is very expensive (20000 pounds to 60000 pounds per course) and you can still get re-infected.
There are no vaccines.
A 25 yo IVDU is admitted and known to be HIV positive.
Med student is asked to take blood test and after the blood test pricks her thumb with the same needle.
What should she do?
(Think post-exposure prophylaxis (PEP))
Test for HIV, Hep C and Hep B.
Immediate measures such as first aid where you bleed and wash the wound.
Collect blood from patient to see their levels and disease.
Inform occupational health
Chech the med students Hep B vaccination status.
Assess risk and need for immediate HIV PEP
Give ARVs for 28 days (3x) and start it as soon as possible max up to 72 hours after needlestick.
HIV test at baseline 1 month and 3 months after initial test.
