5 - Liver disease and Hep B Flashcards
Structure of the hepatitis B virus
Double stranded DNA virus
Epidemiology of hep B
most common cause of hepatitis
350million worldwide affected
HbeAg antigen
Secreted by infected cells (marker for active infection)
HBsAg antigen
First marker to appear and causes the production of anti-HBs
HbsAg 1-6months
Acute disease
HbeAg 1-3 months
Results from breakdown of infected liver cells
Marker for infectivity
Anti-HBc
Core antibody
implies previous or current infection
o IgM anti-HBc appears during acute or recent infection (6 months)
o IgG anti-HBc persists for life
Anti-Hbs (surface antibody) implies
Immunity
due to exposure or immunisation
negative in chronic disease as no immunity in this case
Transmission of hep b
Sexual intercourse
Blood
Bites from an infected person
Vertical - mother to infant
Clinical presentation of hep b
Acutely presents as flu-like Anorexia, loss of appetite Nausea RUQ pain Fever Malaise Jaundice
Signs of decompensated liver disease
Ascites
Encephalopathy
GI bleeding (varices)
Chronic hep B
> 6 months
if inactive - no significant harm
Carriers present with nausea, fatigue, RUQ pain
May progress to liver fibrosis, cirrhosis and HCC
Acute hep b symptoms
weight loss anorexia Nausea fatigue muscle or joint pain
Chronic hep b symptoms
Weight loss, anorexia, fatigue, bleeding easily, dark coloured urine, itchy skin, confusion, drowsiness, ascites, oedema, jaundice, spider naevi, hepatosplenomegaly.
Hep b specific investigations
HBsAg, HBeAg, anti-HBe, anti-HBs, anti-HB core
HBV genotype
HBV DNA quantification
Quantitative HCV RNA polymerase chain reaction (1 or 2 weeks post infection)
HCV antibody enzyme immunoassay (ELISA)
General liver test
FBC Liver Enzymes (ALT, AST, GGT), Bilirubin, Albumin, Clotting, autoantibody screen
Biomarkers of liver injury
Alanine transaminase (ALT) and Aspartate aminotransferase (AST)
Alkaline phosphate
Biomarker for biliary tree pathology
Gamma-glutamyl transferase
Alcohol involvement
Hep B treatment
Avoid unprotected sex
Avoid alcohol
Support- analgesia, antiemetics, fluids
Treatment of hep b if chronic infection
lifelong treatment
Antivirals - pegylated inferferon alfa-2a for 48 weeks
or
NtRTI - nucleotide analog reverse-transcriptase inhibitor
e.g. tenofovir, entecavir, sofosbuvir, grazoprevir
Complications of HepB
Hepatocellular carcinoma
Cirrhosis
Fulminant liver failure
What is cirrhosis
Irreversible liver damage
end stage of liver disease
Causes of cirrhosis
Alcohol abuse HBV (most common), HVC Genetics - wilsons, haemochromatosis Autoimmune - Primary Biliary Cholangitis, Primary Sclerosing Cholangitis Drugs - Amidarone, methotrexate
Pathogenesis of cirrhosis
o 1) alcohol/virus 2) constant stress on liver 3) inflammation and destruction of hepatocytes 4) liver cell necrosis 5a) stellate cell activation production of fibrogenic mediators ( TGF-B) increased collagen fibrosis 5b) remaining liver cells that are damaged form colonies (regeneration nodule formation) 6a) macronodular -chronic hep b 6b) micronodular <3mm caused by alcohol.
Compensated liver
Liver can still undergo its function, may be asymptomatic or have non-specific symptoms such as weight loss, fatigue, weakness
What is decompensated liver
Liver can’t function and do its normal jobs (jaundice, pruritus, ascites, hepatic encephalopathy, easy bruising
