Viral hepatitis Flashcards
What is the dual blood supply of the liver?
hepatic portal vein
hepatic arteries
What blood does the hepatic portal vein carry?
venous blood from spleen, stomach, pancreas + small intestine
Define hepatitis
acute or chronic parenchymal liver damage
What is the dominant symptom of hepatitis?
jaundice (icterus)
(detectable clinically when serum bilirubin >50 micromol/L
Hepatitis histological features
hepatocytes show degenerative changes (swelling, cytoplasmic granulation, vacuolation)
hepatocytes undergo necrosis (become shrunken, eosinophilic councilman bodies)
necrosis maximal in zone 3
Hepatitis causes
viral infections
bacterial infections
drugs
alcohol
poisons
other (pregnancy, Wilson’s disease, circulatory insufficiency)
What infectious agents can cause hepatitis?
systemic viral infections:
- EBV
- CMV
- HSV
- VZV
- yellow fever
- viral haemorrhagic fevers
- rubella
- mumps
- adenovirus
- HIV
- Coxsackie B
Bacterial infections:
- leptospira
- coxiella
- brucella
- borrelia
Hepatotropic viruses
What are the major hepatotropic viruses?
Hep A, B, C, D, E
Most common blood borne infection in UK
Hep C
What disease processes are associated with HCV?
liver disease
diabetes
B-cell proliferative disorders
depression
cognitive disorders
Most important risk factor for HCV infection?
injecting drugs
Risk factors associated with transmission of HCV?
transfusion with infected blood
injecting drug use
haemodialysis (rare in UK)
accidental injuries with needles/sharps
sexual/household exposure
multiple sex partners
birth to HCV-infected mother
Diagnosis of HCV infection
HCV antibody - diagnoses in chronic disease (not useful acutely as takes 12 weeks for antibody to appear)
HCV RNA - can be used in acute phase
HCV antigen
What antivirals can be used to treat HCV?
protease inhibitors - Telaprevir, Boceprevir
NS5A inhibitors - Ombitasvir, Elbasvir
NS5B inhibitors - Sofosbuvir, Dasabuvir
When does HDV occur?
occurs as a result of either an acute HBV coinfection or a superinfection in patients chronically infected with HBV
What is HDV coinfection?
infection with both HBV and HDV in HBV-susceptible individuals
presentation resembles acute Hep B
What is HDV superinfection?
infection with HDV in an individual chronically infected with HBV
presents as acute severe hepatitis or exacerbation of chronic Hep B
Factors associated with HDV infection
close contact with anti-HDV positive person
IVDU
sexual contact with an IVDU
liver cirrhosis
geographical origin (high prevalence area)
How is Hepatitis E diagnosed?
serological tests needed
Anti-HEV IgM during acute phase
PCR virus load to monitor treatment response
Prevention measures for HEV
avoid drinking water of unknown purity, uncooked shellfish, and uncooked fruit/veg
in UK - avoid eating inadequately cooked pork meat
Vaccine developed - used in China + Nepal
Modes of transmission of Hep B virus
sexual - sex workers and MSM
parenteral - IVDU, health workers
perinatal - antenatal women chronically infected with HBV
transfusion - screening + viral inactivation have eliminated this in Europe
Prevention of HBV infection
UK antenatal screening
renal unit policy
exposure prone procedures for HBV infected healthcare workers
global eradication programme (immunisation)
Hep A virus transmission
close personal contact
homeless persons - poor hygiene
drug use - poor hygiene
contaminated food/water
blood exposure (rare)
