Global Perspectives of Viral Liver Disease Flashcards
What do all hepatitis viruses cause
Transamintis
What is hepatitis A
RNA virus (HAV)
How is hepatitis A spread
Food and water borne (sexual)
Why is Hep A not as common anymore
Effective vaccine
How long is the Hep A incubation period
3 weeks
Describe Hepatitis B
DNA virus (HBV)
How is Hepatitis B spread
Blood and body fluids (BBV)
What is the most common transmission of Hepatitis B
Vertical transmission
Explain how clearing of Hepatitis B is age dependent
Newborns= 5% chance of clearing disease. In adult life most clear the virus (95%) (never really cleared just locked inside liver cells
What is the incubation period of Hepatitis B
6 months, therefore delayed onset of symptoms
How much of the population is infected with Hepatitis B
4%
What is Hepatitis C
RNA virus
How is Hepatitis C spread
Blood and bodily fluids borne
What is Hepatitis C more due to
Less sexual transmission, more used of IV drugs
What percentange of drug users and Hepatitis C positive
50%
What is the incubation period of Hepatitis C
3 weeks
How many people clear a Hepatitis C infection
30%
What percentage of the population is infected with Hepatitis C
2-3%
What is Hepatitis D
RNA virus
Who gets Hepatitis D
Only people with Hepatitis B
What is Hepatitis E
RNA virus
How is Hepatitis E spread
Food and water borne
Which is more common, Hepatitis A or Hepatitis E
Hepatitis E
What is the risk of transmission on contact with infected blood
Rule of thirds: Hep B = 33%, Hep C = 3%, HIV = 0.3%. Other viruses: Cytomegalovirus, Epstein-Barr virus
Describe acute hepatitis
Spontaneous viral clearance by immune system, usually within weeks-months, Hep A, Hep E, Hep B (unless acquired during infancy)
Describe chronic hepatitis
Immune system fails to clear virus, viral persistence for > 6 months, usually long-term (unless treated), Hep B, Hep C (80% of cases)
Describe what cholestatic is
Blockage (LFTs = ↑ alk phos and ↑gamma)
Describe transaminitis
Something toxic to cells (LFTs = ↑ ALT, ↑ AST)
Describe the transmission/ groups at risk of Hep A and Hep E
FOOD AND WATER, Endemic in countries with poor sanitation, Travellers, Person-to-person, Gay men (due to faecal contact), Animal contact (Hep E) - European pig meat, Pregnant women have specific serotype, this or transplant leads to immunosuppression, where acute infection can become chronic
Describe the transmission/ groups at risk of Hep B and Hep C
BBV, Blood transfusion: Haemophiliacs, IV drug use/sharing, Sexual: HBV = 30% risk, HCV = Rare, Vertical: HBV = 5-90% risk, HCV =
Describe the clinical features of acute hepatitis
Symptoms: Fever, malaise, nausea, vomiting, jaundice, dark urine, diarrhoea.Signs: Jaundice, tender, enlarged liver. Investigations: Deranged LFTs: ↑ bilirubin, ↑ transaminases, liver ultrasound and viral serology.
What are the complications of chronic viral hepatitis
Liver fibrosis/cirrhosis - variable progession over years. End stage liver disease- portal hypertension/ascites (backflow leads to leaking, as well as decreased albumin production, which is meant to hold fluid within the blood system), bleeding (oesophageal varices) and liver failure. Hepatocellular carcinoma
Describe the course and diagnosis of Hepatitis A
Incubation period = 2-6 weeks. Serological diagnosis: Detection of specific antibodies. Anti-HAV IgM = Recent infection. Anti-HAV IgG = Past infection or immunisation
Describe the course and diagnosis of Acute Hep B
Incubation period = 6 weeks - 6 months. Detection of viral surface antigen (HBsAg) in serum indicates infection (acute and chronic). Surface antibody (anti-HBs)- indicates viral clearance, post vaccination
Describe chronic Hep B
Risk of developing chronic infection depends on age at time of infection. Persistent HBsAg. Presence of HBeAg (part of viral core)- high infectivity, high risk of liver damage, viral DNA detectable in plasma (PCR)
Describe the clearance and course of Hep C
Usually asymptomatic during acute stage. Most patients develop chronic infection. ‘Silent killer’ - end stage liver disease often decades after infection. Effective treatment available - curative
Describe the prevention of hepatitis A & E
Food water and hygiene, hand washing, vaccination (HAV)
Who is the HAV vaccination recommended for
Travelers to endemic areas, Patients with chronic liver disease, MSM, HIV, Sewage workers, Staff in residential institutions
Describe active component of the Hep A immunisation
Prepared from inactivated whole Hep A virus, single dose by IM injection, booster dose at 6 months gives life long immunity, live attenuated vaccine available but rarely used
Describe passive component of the Hep A immunisation
Human normal immunoglobulin (HNIG) can be used for port-exposure protection of contacts (together with active vaccine)
Describe the prevention of Hep C & B
Screen/viral inactivation of blood products for transfusion, safe sex, avoid needle/syringe sharing
Who is the Hep B vaccine recommended for
Healthcare workers, Injecting drug users, MSM, HIV, Chronic liver disease, chronic kidney disease, Travelers to high prevalence areas, Post-exposure
Describe active component of the Hep B immunisation
HBsAg prepared in yeast cells by recombinant DNA technology (sub-unit of vaccine, doses in 3 IM injections, response to vaccine can be checked by measuring levels of HBs antibody (>100 IU/ml protective)
Describe passive component of the Hep B immunisation
Specific Hep B immunoglobulin (HBIG) can be used for post-exposure protection of contacts (together with active vaccine) - Prepared from plasma of immunised donors.
How do you prevent mother-to-child transmission of Hep B
Babies born to mothers with chroic BV. Vaccination of infant: 3 dose schedule starting at birth. Passive immunisation of mother eAg + High viral load - Single dose of HBIG. Anti-viral drug therapy to mother during pregnancy - reduces viral load at time of delivery
What is innate immunity
Non-specific, general, immediate response, no immunological memory
What are the two aspects of the innate response
Humoral and cellular
Describe the humoral aspect of innate immunity
Pattern receptors, complement, enzymes, cytokines
Describe the cellular aspect of innate immunity
Phagocytes, natural killer cells
Describe adaptive immunity
Specific to antigen, lag time from exposure to response, immunological memory after exposure
What are the twp aspects of adaptive immunity
Humoral and cellular
Describe the humoral aspect of adaptive immunity
Antibodies and cytokines
Describe the cellular aspect of adaptive immunity
T cells and B cells
What are vaccine types
Preventative vs therapeutic. Active vs passive