Public health and viral hepatitis Flashcards
What is the management of chronic HCV infection?
Rx dependent on genotype (1-6)
IFN treatments no longer recommended
Aim to have undetectable HCV titre of RNA at 6 months post-Rx
Current Rx: proteosomal inhibitors combo ± ribavirin
What are the side effects with ribavirin?
haemolytic anaemia,
cough.
Women should not become pregnant within 6 months of stopping ribavirin as it is teratogenic
What are the side effects of interferon-alpha based Rx?
flu-like symptoms, depression, fatigue, leukopenia, thrombocytopenia
How is chronic hepatitis C defined?
persistence of HCV RNA in blood for 6 months after exposure
What are the potential complications of chronic HCV infection?
rheumatological problems: arthralgia, arthritis
eye problems: Sjogren’s syndrome
cirrhosis (5-20% of those with chronic disease)
hepatocellular cancer
cryoglobulinaemia: typically type II (mixed monoclonal and polyclonal)
porphyria cutanea tarda (PCT): it is increasingly recognised that PCT may develop in patients with hepatitis C, especially if there are other factors such as alcohol abuse
membranoproliferative glomerulonephritis
What are the main stages in viral hepatitis Sx presentation/infection?
Stage 1: NO Sx
infected, viral replication
Stage 2: NON-SPECIFIC Sx
- anorexia, nausea, vomiting, arthralgia, malaise, fatigue, itchy skin
- difficult to Dx based on Sx
Stage 3: DARK URINE, PALE STOOLS
- GI Sx and malaise
- jaundice
- may also develop RUQ pain and hepatomegaly
Stage 4: Sx RESOLVE
- LFTs return to normal
- jaundice disappears
How do some people not realise they have chronic hepatitis?
the initial (acute) infection may have been insidious and likely asymptomatic Would not be able to tell unless there were Sx
What is a clinical diagnosis of viral hepatitis based on?
- history (jaundice and other associated Sx)
- exposure (risk groups)
- grossly elevated ALT/AST, moderately elevated GGT and ALP
- vaccination history: (HAV and HBV absent)
- Absence of other Sx indicating neoplasia or other causes
What is a laboratory Dx of viral hepatitis based on?
Serology: detection of Ab and/or Ag
- usually by enzyme linked assays
- detection of RNA or DNA by PCR
What are alternative older terms for HAV and HBV?
HAV: infectious jaundice
HBV: serum hepatitis (as spread via blood products)
What are the main points about HAV?
most infectious before Sx develop, but many are asymptomatic and mild. More severe in those with chronic liver disease.
Sx more common in adults than in children
Very rarely fatal
No chronic infection, individuals are immune following infection
No Rx, vaccine available
Faecal oral transmission
What is the relationship between Sx and Ig serotype for most viral infections?
by the time Sx appear, there will be detectable IgM titres
exception: measles
What are the methods to prevent HAV?
PRE-EXPOSURE
immunisation with purified inactivated whole virus vaccine
at risk groups in UK and travellers are encouraged to get vaccine
POST-EXPOSURE
public health will contact at risk individuals in outbreak
Vaccines and/or immunoglobulins are given
What are the main points about HBV?
spread by bodily fluids e.g. blood Vertical transmission is an important problem
many asymptomatic infections, but can cause fulminant infection leading to death
chronic infection leads to cirrhosis and HCC risk, but can be treated to keep viral load low
Vaccine available
Large number of people worldwide are infected with HBV
Highest susceptibility for chronic HBV with acute infection at birth (90%)
What are the different types of HepB Ag?
HBsAg: surface Ag, produced in mass so one of the first Ag that the immune system will generate Ab against
HBcAg: nucleocapsid core Ag, associated with having had an infection either chronic or resolved
HBeAg: only present in some strains of HBV, usually indicates acute or chronic active disease
HBeAg is a splice variant of HBcAg
What is the typical acute and chronic timelines for viral hepatitis?
acute < 6 months
chronic > 6 months (up to years)
How is the degree of infectivity determined?
levels found by quantifying the amount of HBV virus
What are the implications for a HIGH INFECTIVITY CARRIER?
much higher risk of developing serious complications from chronic infection e.g. HCC and cirrhosis
Also higher risk of being infectious (important for infected mothers for e.g. vertical transmission)
+ve: HBsAg, HBeAg, anti-HBs (total), HBV DNA
What are the serology results for someone with successful HBV vaccination likely to show?
positive Anti-HBs (surface antigen, total)
negative on all other markers
How is HBV infection prevented?
PRE EXPOSURE
Adults: given to at risk groups
Screening an immunisation of health care workers performing exposure prone procedures
All babies now offered HBV vaccine
POST EXPOSURE
vaccination and Ig can be administered
HCWs, babies of infected mothers, sexual exposure
How is HBV screened for in expectant mothers?
screened at ante-natal clinic for HBV carriers
vertical transmission is interrupted for baby via administration of immunoglobulins (passive immunity) and vaccine at birth (active immunity)
At what ages is the HBV vaccine available to babies?
8 weeks
12 weeks
16 weeks
Also in 6-in-1 vaccine
What is the Rx of HBV?
treatable in some patients
PEGYLATED INTERFERON and/or antiviral agent
Some interferon free Rx also available
Antiviral agents include: entecavir and tenofovir
those more likely to be treated if co-infected with HIV
Rx dependent on stage and illness type
Referral to hepatologist
What are the main points about HCV?
Spread by bodily fluids
many infections are asymptomatic
Chronic infection is common and may lead to cirrhosis and HCC
Chronic infection is treatable, but re-infection may occur
No vaccine available
HCV 10-100x less infectious than HBV
When are you most likely to Dx HCV in the course of its infection?
more likely to make Dx in chronic stages
acute phases are often asymptomatic
RNA and abnormal LFTs are usually first marker to be detected in blood test
What serology results would you expect in an infected HCV individual who has been successfully treated?
HCV RNA: NEGATIVE
IgG Ab: POSITIVE
What serology results would you expect in an infected individual with chronic HCV?
HCV RNA: +ve
IgG Ab: +ve
How is HCV infection prevented?
no vaccine
Prevention is largely based on avoiding exposure
What is the Rx for HCV?
Curable in some individuals
response influenced by viral and host genotypes
Currently Rx: Antivirals and INTERFERON FREE Rx
What is the old terminology for HCV?
NANB = non A non B hepatitis
What are the main points about HDV?
transmitted by same routes as HBV
required HBV co-infection to mediate HDV infection
Rx: Target HBV to treat HDV
no vaccine, but HBV vaccine will prevent HBV and so HDV infections
How is HDV Dx?
patient must have HBV infection
then detection of HDV RNA via PCR
What are the main points about HEV?
Faecal oral transmission
may be acquired from pork
15-64 day incubation period
Generally mild, often asymptomatic
Can be more severe in pregnancy. Especially Asian genotypes that can cause fulminant disease.
Rx not usually needed
Vaccine available in China
What lifestyle changes can be implemented to manage viral hepatitis?
- prevent further damage to liver
- avoid ingesting any hepatotoxic items e.g. EtOH
- check medications with doctor to avoid further liver compromise
- prevent further spread to others
- Avoid IVDU
- Do not share personal items
Who is responsible for notification of hepatitis?
Clinician: duty upon presentation of Sx indicative of hepatitis
Lab: duty to notify once causative agents 9HAV, HBV, HCV, HDV, HEV) are identified
