Session 8: Blood Borne Viruses - Viral Hepatitis

Question 1

Definition of hepatitis.

Answer 1

Inflammation of liver.

Question 2

Where does hepatitis viruses replicate?

Answer 2

In the hepatocytes (hepatotropic) Destroys hepatocytes as well.

Question 3

Label the diagram.

Question 4

Explain the production and excretion of bilirubin.

Answer 4

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.

Question 5

Give types of jaundice. Give cause as well.

Where do they take place?

Answer 5

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.

Question 6

Causes of intrahepatic jaundice.

Answer 6

Viral hepatitis
Drugs
Alcoholic hepatitis
Cirrhosis
Autoimmune cholangitis
Pregnancy

Question 7

Causes of extrahepatic jaundice.

Answer 7

Any obstruction of bile:

Common duct stones
Carcinoma
Biliary stricture
Sclerosin cholangitis
Pancreatitic pseudocyst

Question 8

Give liver function tests.

Answer 8

Bilirubin

Liver transaminases (ALT, AST)

Alkaline phosphatase (ALP)

Albumin

Tests of coagulation like clotting factors, INR and PT.

Question 9

If a blood test comes back with elevated Bilirubin and ALT but normal ALP and normal Hb. What does that suggest?

Answer 9

Reduced liver function.

No damage to biliary tract (ALP).

No haemolysis (Hb)

Intra-hepatic jaundice

Question 10

Transmission of Hep B. Who’s at risk?

Answer 10

Vertical transmission most common (75% of cases)

Sexual contact

People who inject drugs

Close household contacts

Significant blood exposure

HCW via needlestick injuries

Question 11

Symptoms of Acute Hep B.

Answer 11

Can vary and also be asymptomatic however:

Jaundice
Fatigue
Abdo pain
Anorexia/Nausea/Vomiting
Arthralgia

Question 12

Prevalence of Hep B becoming chronic.

Answer 12

<10% of infected as adults

90% if infected in infancy in Asia/China

Question 13

Serology of Hep B.

Answer 13

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.

Question 14

Definition of chronic Hep B.

Answer 14

Persistence of HBsAg after 6 months (surface antigen).

25% chronic infections leads to cirrhosis and 5% will develop hepatocellular carcinoma.

Question 15

Treatment of hep B

Answer 15

No cure so life-long anti-virals to suppress viral replication may be needed. It is however not required for everyone.

Question 16

How do you prevent Hep B?

Answer 16

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

Question 17

Complete the table

Answer 17

Question 18

Transmission of Hepatitis C. Who is at risk?

Answer 18

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

Question 19

Once contracted Hep C how many will be chronically infected?

Answer 19

80%

Question 20

Complications of chronic Hepatitis C infection.

Answer 20

Decompensated liver disease

Hepatocellular carcinoma

Needing liver transplant

All this from chronic liver disease/cirrhosis

Question 21

Symptoms of hepatitis C (acute or chronic)

Answer 21

80% have no symptoms

20% get fatigue, anorexia, nausea and abdo pain in right upper quadrant.

Question 22

Blood tests for hepatitis C.

Answer 22

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.

Question 23

Treatment of Hep C.

Answer 23

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.

Question 24

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))

Answer 24

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.