M33- Viral hepatitis in dentistry Flashcards
what is the chief /sole clinical manifestations of hepatitis viruses?
liver disease
what is the liver involved in?
in the breakdown and excretion of toxins and synthesis of glucose and some proteins
what colour is bilirubin?
yellow
what are the different types of hepatitis viruses?
Hepatitis A virus Hepatitis B virus Hepatitis C virus Hepatitis D virus Hepatitis E virus
who are the only people infected by hep D?
Infection only occurs in people already infected with Hepatitis B virus
(co infection of B and D at the same time or superinfection , of B first , then D)
what does the infection of hep D do to the prognosis of hep B?
worsens the prognosis
what are the 2 types of hepatitis?
- acute
- chronic
what is acute hepatitis?
recent onset ( few weeks )
what hep types can be acute?
Hep A, Hep B, Hep C, Hep E
In UK Hep E has become most common
what effects does acute hepatitis have?
- Jaundice
- Pale stools
- Dark urine
what are the complications of acute hepatitis?
-Chronic hepatitis
-Acute liver failure :
<1% of clinical cases of acute viral hepatitis
what is chronic hepatitis?
-Months / years:
>definition: at least 6 months of infection
>complications after decades
what hep types can be chronic?
- Hep B and Hep C, never Hep A, Hep E only if immunocompromised
- In UK Hep C is most common cause
what can chronic hepatitis be in the early years?
asymptomatic
when is chronic hepatitis picked up?
screening
what are the complications of chronic hepatitis?
- Cirrhosis chronic liver failure
- primary liver cancer
- > 30% cases of chronic viral hepatitis will develop serious complication if left untreated for decades
who is a patient with hepatitis referred to?
- physician
- notifiable
what is the summary of Hepatitis A?
- Faecal oral spread
- Not blood borne
- More common in developing world
- Vaccine preventable
- Causes acute never chronic hepatitis
what is the summary of hepatitis E?
- Faecal oral spread
- Not blood borne
- More common in developing world
- Not vaccine preventable
- Causes acute never chronic hepatitis (in immunocompetent)
- Can be caught in UK from some animals / meats (pigs, deer, rabbits)
How is hep b virus and hep C virus transmitted?
-Blood borne spread: >injecting drug use >blood products >needlestick and blood splash -Sex : >more for Hep B than Hep C -Mother to child
Name the risk groups for Hep B and Hep C in the UK.
-Injecting drug users (past or current)
-Greater number of sexual partners : at least for HBV
-Babies of infected mothers
-Born in areas of higher prevalence in pre-vaccine era
-Blood product exposure
: especially in unscreened blood pre-1991
How can hepatitis be prevented?
- Reduce exposure
- Use vaccination
Describe hepatitis B prevention.
- Clean needles and syringes for injecting drug users
- Safe sex
- Screen blood transfusions
- Vaccinate high risk groups and health care workers
- Treatment as prevention?
Describe hepatitis C prevention.
- Reduce exposure as for Hep B
- No vaccine is available
- Treatment as prevention?
what is the treatment of chronic viral hep B?
Numerous antivirals now available, they are suppressive rather than curative, so lifelong therapy required. Fairly safe therapy.
what is the treatment of chronic viral hep C?
-Combination of 2 or 3 antivirals will cure >90%:
>precise antivirals used depends on genotype of virus (1 to 6)
>rapidly developing field, many new antivirals in recent years
-Significant side effects of early regimes being reduced by new combinations
-Antivirals given in short courses a few months long
-Reinfection possible
what does the decision to treat what patient depend on?
Which patients to treat depends on clinical evaluation to determine who is at most risk of progressing to complications of chronic infection
what is important to remember in reducing exposure during health care?
- Standard precautions
- Unreasonable to expect to identify all individuals with a blood borne virus infection
what actions are used to reduce exposure during health care?
- Wear gloves
- Mask and eye protection may be appropriate
- Correct disposal of sharps
- Good sterilisation (autoclave) or use of single use devices
- Vaccination against Hep B
- Disinfect surfaces (with e.g. hypochlorite)
what lab test can be used for hepatitis ?
Clotted blood (gold top bottle)
what is tested in labs for the presence of Hep B acute or chronic?
- HBsAg (Hepatitis B surface antigen)
- All HBsAg +ve people are best considered to be infectious
who is more likely to progress to complications soon in Hep B?
those that either present (in addition to HBsAg) Hep B DNA are very infectious
what is present in those that have been successfully vaccinated and in those that have completely recovered from acute hep B?
Anti-HBs (antibody to HBsAg)
who has anti- HCV (antibody to hep C virus)?
present in people with acute or chronic infection but also in those who have recovered
why are all anti-HCV +ve people considered infectious?
Only a minority recover spontaneously
what is the lab test for hep C?
- Hep C RNA test (Hep C PCR test)
- Positive in infected anti-HCV +ve people but not in those that have recovered
Describe the fitness to practice for hepatitis.
- Must be HBsAg negative :Or if positive must have HBV DNA at very low level (<200 IU/mL) in blood
- Must be Hepatitis C virus antibody negative :Or if positive must be Hepatitis C RNA negative
