Viral Hepatitis Flashcards
Hepatitis A - Transmission
Faecal-oral
Poor hygiene/overcrowding
Some imported cases
Clusters = gay men, injecting drug users
Hepatitis A - Clinical
Acute hepatitis, no chronic infection
Peak incidence of symptomatic disease in children/younger adults
Usually ill for a few weeks then get better
Hepatitis A - Lab Conformation fo Acute Infection
Clotted blood for serology
Hepatitis A IgM (usually detectable from onset of disease)
Hepatitis A - Control
Hygiene
Vaccine prophylaxis
Hepatitis E - Clinical
Acute hepatitis, no chronic infection
Peak incidence of symptomatic disease in children/younger adults
Usually ill for a few weeks then get better
Some immunocompromised humans can become chronically infected
Hepatitis E - Incidence
More common in tropics
Has become more common than Hep A in UK
Hepatitis E - Transmission
Faecal-oral
UK cases are thought to be through zoonoses (esp. pigs, deer and rabbits)
Hepatitis E - Tropical Genotypes
In pregnant women, causes severe disease and likely death
Hepatitis E - Control
No vaccine available yet
Hepatitis D - Incidence
Can only infect those with Hep B
Exacerbates Hep B infection
Hepatitis D - Co Infection
Have Hep B and Hep D at the same time
Hepatitis D - Superinfection
Have Hep B, then go on to develop Hep D
Hepatitis B - Transmission
Sex
Mother to child
Blood
Hepatitis B - Higher Risk
People born in intermediate/high prevalence areas
Multiple sex partners
People who inject drugs
Children of infected mothers
Hepatitis B - HBsAg
Hepatitis B Surface Antigen
Present in the blood of all infected individuals
Chronic infection = present for >6 months
Hepatitis B - Clinical
Risk of chronic infection decreases with increasing age of exposure
Risk of acute hepatitis increases with age at exposure
Death is more likely to result from a chronic infection than an acute infection
Hepatitis B - HBeAG
Hepatitis B e Antigen
Usually present in highly infectious individuals
Hepatitis B - Hep B DNA
Always present in highly infectious individuals
Used to predict risk of chronic liver disease and monitor therapy
More sensitive than HBeAG
Hepatitis B - Hep B IgM
Most likely to be present in recently infected cases
Hepatitis B - Control
Safe blood Safe sex Needle exchange Prevention of needlesticks Screening of pregnant women Pre-exposure vaccination Post-exposure prophylaxis (vaccine + HBIG)
Hepatitis C - Transmission
Less easily transmitted by sex than Hep B
Mother to child
Blood
Hepatitis C - Clinical
75% of cases result in chronic infection
Natural history not dependent on age at time of infection
Hepatitis C - Lab Conformation
Test for antibody to Hep C \+ve = Past or active infection -ve = Not infected Test for Hep C RNA by PCR \+ve = Active infection -ve = Past infection
Hepatitis C - Control
No vaccine
Must minimise exposure
Hepatitis A - Natural History
Infection
Mostly asymptomatic/acute hepatitis -> resolution
Rarely (e.g. elderly) acute liver failure -> death or resolution
Natural History of Chronic Infection - Hep B
Spontaneous cure not uncommon, eve after many years of infection
Natural History of Chronic Infection - Hep C
Once chronic infection is established, spontaneous cure is not seen
Hepatitis C - Natural History
Infection
Mostly asymptomatic -> chronic infection -> chronic hepatitis -> cirrhosis -> chronic liver failure/cancer -> death
25% resolution from asymptomatic disease
Hepatitis B - Natural History, Adult Infection
Infection
Most asymptomatic/acute hepatitis -> resolution
Less than 5% develop chronic infection/chronic hepatitis (some of these cases still resolve)
Few result in cirrhosis -> chronic liver failure/cancer -> death
Hepatitis B - Natural History, Infection at Birth
Similar to Hep C
high levels of chronic infection and complications
Management of Acute Viral Hepatitis
Symptomatic No antivirals given Monitor for encephalopathy Monitor for resolution Notify Public Health Immunise contacts Test/vaccinate for other at risk infections
Management of Chronic Viral Hepatitis
Antivirals Vaccination Infection control Decrease alcohol intake Hepatocellular carcinoma awareness/screening
Antiviral Treatment - Who?
Chronic infection
Risk of complications = inflammation present
Fit for treatment = liver cancer contraindicates, cirrhosis and HIV make treatment more difficult
Patient issues = side effects, lifestyle issues, attitude to treatment
Antiviral Treatment - When?
Before complications
Evidence of inflammation
Patient is ready
Clinical priority (e.g. HIV may be treated an controlled first)
Antiviral Treatment - Interferon Alpha
Human protein
Injected
Genetically engineered
Antiviral Treatment - Interferon Alpha - Side Effects
Common = Flu like Chills Sore muscles Malaise
Rarer but severe =
Thyroid disease
Autoimmune disease
Psychiatric disease
Therapy for Chronic Hepatitis B
Option 1
Interferon only
Sustained cure possible, but only minority gain benefit and serious side effects
Option 2
Suppressive antiviral drug
Safer, but only suppression so no cure and possible resistance
Aims of Chronic Hepatitis B Therapy
Reduce HBV DNA, lose HBeAg, lose HBsAg Improve liver biochemistry Improve histopathology Reduce infectivity Reduce progression Reduce mortality
Aims of Chronic Hepatitis C Therapy
Response defied by loss of HCV RNA in blood sustained 6 moths after therapy (aka SVR) Improve liver biochemistry Improve histopathology Reduce infectivity Reduce progression Reduce mortality
Principles of Hepatitis C Therapy
Choice of antiviral based on = Genotype of virus, viral load Genotype of patient's interferon response genes Stage of disease Past treatment experience Likelihood of side effects Cost effectiveness
Hepatitis C Therapy - Newer Antivirals
Simeprevir, Ledipasvir, Daclatasvir =
Used in certain genotypes in combo with other drugs
Safe and well tolerated
Sofosbuvir =
Active against all genotypes in combo with other drugs
Safe and well tolerated
