Hepatology Flashcards
List key clinical features of viral hepatitis. (10)
Viral hepatitis causes:
- Jaundice
- Scleral icterus
- Hepatomegaly
- RUQ pain and tenderness
- Anorexia
- Nausea and vomiting
- Fever
- Fatigue and malaise
- Dark urine
- Pale stools
How is hepatitis A transmitted?
Fecal-oral route
What type of virus is hepatitis B?
Hepadnaviridae family
Circular DNA virus, partially double-stranded
How is hepatitis B transmitted? What is the most common route?
Present in several bodily fluids and transmitted by multiple routes, including:
- Blood
- Sexual contact
- Vertical
In areas of high prevalence, vertical transmission is the most common. In areas of low prevalence, IVDU is the most common.
Describe the life cycle of Hepatitis B.
HBV enters the body and localises in hepatocytes. It is uncoated and the nucleocapsid travels to the nucleus. In the nucleus, the viral DNA polymerase synthesizes the missing part of the circular DNA to make a complete ds-DNA molecule. Then there is ‘RNA-dependent DNA synthesis’ in which RNA polymerase makes mRNA from the DNA, and the RNA is used as a template to produce DNA by reverse transcription. Once replicated, the virus buds through the cell membrane.
What is the prognosis for hepatitis B infection?
Hepatitis B infection can become chronic. The risk depends on the patient’s age. The risk is highest in neonates (90%), and lowest in adults (less than 5%).
In acute HBV infection, what is first detected on serology?
HBsAg
A patient with acute HBV recovers from the infection. Describe what this would look like on serology.
With the acute infection the patient has detectable HBsAg. As the patient recovers, the HBsAg disappears and anti-HBs appears.
What does anti-HBs mean? How can you differentiate between the possibilities?
anti-HBs is present if the patient has had a past HBV infection, or if the patient has been vaccinated against HBV. To differentiate between these, look at the anti-HBc IgG. This will be present if there has been a past infection, but absent if there has been vaccination.
What indicates progression of acute HBV infection to chronic HBV infection on serology?
HBsAg persists for > 6 months.
What does the following indicate:
- HBs Ag detected & anti-HBc IgM detected?
- HBsAg not detected & anti-HBs detected?
- anti-HBs detected and anti-HBc IgG detected?
- anti-HBs detected and anti-HBc IgG not detected?
- HbsAg present for > 6 months?
- Acute HBV infection
- Patient recovering from acute HBV infection
- Past acute HBV infection
- Vaccination for HBV
- Chronic HBV infection
What type of virus is Hepatitis C?
Flaviviridae family
ssRNA virus, (+) sense
How is hepatitis C transmitted?
Mainly by IVDU
What are the risk factors for HCV infection?
IVDU Health care workers - e.g. needlestick injury Blood transfusion prior to screening Tattoos Piercing Organ transplantation Haemodialysis
What are the risk factors for HBV infection?
IVDU
Sexual risk factors - MSM, multiple partners, not using barrier protection
Living in or travelling to an endemic region
Prisoners
What is the prognosis of hepatitis C?
70-90% of patients will develop chronic infection with hepatitis C virus
What is the long term effect of hepatitis C viral infection on the liver?
Fibrosis
Cirrhosis
Hepatocellular carcinoma
How would you confirm HCV infection?
First, test for anti-HCV. If this is positive, test for HCV RNA. If this is also positive, then the diagnosis is made.
Describe the MOA of direct-acting antivirals in the treatment of HCV infection.
NS5B polymerase inhibitors - inhibit the synthesis of polymerase, which is required for RNA replication
NS5A inhibitors - inhibit NS5A, which is a cofactor for the polymerase required to replicate viral RNA.
NS3/4A protease inhibitors - inhibit the cleavage of precursor peptides, which blocks the production of functional HCV proteins.
Why is Hepatitis D a ‘defective’ virus?
The virus does not have the genes for its envelope protein. Because of this, it can only replicate in cells that are also infected with Hepatitis B (it uses the HBV surface antigen in its envelope).
How is Hepatitis D virus transmitted?
Blood
Semen and vaginal secretions
How is Hepatitis E virus transmitted?
Fecal-oral via consumption of contaminated food or water; there is minimal person to person spread.