Viral Hepatitis Flashcards
Define viral hepatitis
Hepatitis (hepatocyte necrosis and inflammatory cell infiltration) caused by viruses
Acute <6 months Chronic >6 months
What are the features of the different types of viral hepatitis?
(virus, transmission, incubation, CLD?, liver cancer?)
Hepatitis A Viruses: • HAV - RNA picornavirus Transmission: • Faeco-oral • Saliva Incubation : • Short - 2-6 week no CLD or liver cancer
Hepatitis B Viruses: • HBV -incomplete double stranded DNA Transmission: • Blood + blood products • Sexual • Vertical • Saliva Incubation : • Long - 1-5 months CLD and liver cancer
Hepatitis C Viruses: • HCV - single stranded Transmission: • Blood + blood products • Sexual • Vertical • Saliva Incubation : • Long - 1-5 months CLD and liver cancer
Hepatitis D Viruses: • HDV - incomplete single stranded Transmission: • Blood + blood products • Saliva Incubation : • Intermediate - 1-3 months CLD but no liver cancer
Hepatitis E Viruses: • HEV - RNA Transmission: • Faeco - oral Incubation : • 3-8 weeks no CLD or liver cancer
What are the causes of viral hepatitis?
Hepatitis A
• caused by viral replication in hepatocytes ->
secretion into bile -> excreted in faeces
• Immune response with CD8+ T cells and NK cells -> liver inflammation and
hepatocyte necrosis
• HAV is most infectious just before the onset of jaundice
Hepatitis B
• HBV virion is called the Dane particle: outer envelope of surface protein HBsAg and
inner core/nucleocapsid containing incomplete double stranded DNA and DNA
polymerase/reverse transcriptase surrounded by core proteins – HbcAg + HBeAg
• Antibody and cell-mediated immune responses -> liver inflammation and hepatocyte
necrosis
Hepatitis C
• Antibody and cell-mediated immune responses -> liver inflammation -> fibrosis ->
cirrhosis
Hepatitis D
• Requires HBV to replicate – incomplete RNA particle enclosed in HBsAg
• Occurs as a co-infection or superinfection with HBV
• May develop chronic hepatitis which progresses more rapidly than with HBV
infection alone
Hepatitis E
• acute self-limiting illness
• HEV is carried in dogs, pigs and rodents
• 1-2% of patients develop fulminant liver
failure but this rises to 20% in pregnant
women
• Progression to chronic liver disease only
occurs in immunosuppressed patients
What are the risk factors of viral hepatitis?
Faeco-oral • Shellfish • Contaminated water • Endemic regions with poor sanitation • Men who have sex with men (MSM) due to rimming
Blood + blood products • Blood transfusion • IVDU • Tattoos • Healthcare workers • Sexual • Multiple sexual partners • Men who have sex with men (MSM)
Vertical
• Permucosal from infected
bodily fluids during
childbirth
Saliva
Other risk factors
• Co-infection with HBV, HCV or HIV
What is the epidemiology of viral hepatits?
HAV is endemic in developing countries -> subclinical disease
Better sanitation in developed countries -> symptomatic disease
Incidence is 5000 cases per year in the UK (seroprevalence ~5%)
Particularly affects children and young adults
HBV is common with 350 million carriers worldwide
Low prevalence in the UK
Common in Southeast Asia, Africa and Mediterranean
HCV 0.5-2% in UK
Higher rates in Africa and Middle East (poor sterilisation practices)
High incidence in IVDU (50-60%)
HDV affects all HBV risk groups but particularly IVDU
HEV is endemic in Africa, Asia and Central America
What are the signs and symptoms of hepatitis A and E?
Prodrome Symptoms • Malaise • Anorexia • N&V • Fever • Distate for cigarettes Signs • Pyrexia
Acute Prodromal symptoms disappear after ~ 2 weeks • Jaundice • Dark urine, pale stools • Pruritus Signs • Jaundice • Tender hepatomegaly • Palpable spleen
What are the signs and symptoms of hepatitis B and D?
Prodrome Symptoms • Asymptomatic (70%) • Malaise • Anorexia • N&V • Diarrhoea • Headache • RUQ pain Serum sickness-like illness • Fever • Arthralgia • Polyarthritis • Urticaria • Maculopapular rash Signs • Pyrexia
Acute Symptoms • Jaundice • Dark urine, pale stools Signs • Jaundice • Tender hepatomegaly • Splenomegaly • Cervical lymphadenopathy • Urticaria/ maculopapular rash
What are the signs and symptoms of hepatitis C?
Acute Symptoms • Asymptomatic (90%) • Jaundice (<10%) • Mild flu-like symptoms
What are the signs and symptoms of fulfilment liver failure and chronic hepatitis?
Fulminant liver failure Acute hepatitis + Coagulopathy • Easy bruising and bleeding Encephalopathy • Confusion • Drowsiness • Disorientation
Chronic hepatitis • Fatigue • N&V • Anorexia • Jaundice Chronic liver disease • Weight loss • Coagulopathy • Ascites • Peripheral oedema • Encephalopathy • Variceal bleeding
What investigations are carried out for viral hepatitis?
• Bloods
o Elevated ALT, AST, ALP, bilirubin
o Increased prothrombin time (fulminant liver failure and chronic hepatitis)
• Serology
o Anti-HAV IgM – acute hepatitis A
o Anti-HAV IgG – recovery from hepatitis A
o Anti-HCV IgM – acute hepatitis C
o Anti-HCV IgG – past or chronic hepatitis C
o HCV DNA – detection and genotyping of hepatitis C
o Anti HDV IgM and IgG – hepatitis D
o Anti-HEV IgM and IgG – hepatitis E
• Liver biopsy – assess liver damage/inflammation/cirrhosis/carcinoma
How is viral hepatitis managed?
Hepatitis A&E
Prevention
• Active immunisation with attenuated HAV
• Passive immunisation with IM human Ig (post-exposure prophylaxis)
• Public health – safe water, sanitation and food hygiene
Supportive
• Bed rest
• Antipyretics
• Antiemetics
• Antipruritics e.g. colestyramine
Hepatitis B (&D) Prevention • Blood screening • Instrument sterilisation • Safe sex • Active immunisation with recombinant HBsAg • Passive immunisation with hepatitis B Ig (HBIG) (post-exposure prophylaxis) Acute • Bed rest • Antipyretics • Antiemetics • Antipruritics e.g. colestyramine Chronic • (Pegylated) interferon alpha • Nucleoside analogues e.g. entecavir, tenofovir
Hepatitis C Prevention • Blood screening • Instrument sterilisation • Needle exchange schemes Acute • Bed rest • Antipyretics • Antiemetics • Antipruritics e.g. colestyramine Chronic • Pegylated interferon alpha • Nucleotide analogues e.g. ribavirin
What are the complications of viral hepatitis?
Fulminant liver failure
• Hepatitis A (0.1%)
• Hepatitis B (1%) – may develop more rapidly with HDV superinfection
• Hepatitis C (0.5%)
• Hepatitis E (1-2%; 20% in pregnant women)
Chronic infection
• Hepatitis B (10%)
• Hepatitis C (80%)
Cirrhosis
Hepatocellular carcinoma
Other complications of Hepatitis C • Cryoglobulinaemia • Glomerulonephritis • Arthritis • Porphyria cutanea tarda
What is the prognosis for viral hepatitis?
Hepatitis A&E
• Recovery within 3-6 weeks
Hepatitis B
• 10% develop chronic infection
• Of these 20% develop cirrhosis
Hepatitis C
• 80% develop chronic infection
• Of these 20% develop cirrhosis
