What is the pathogenesis? Firstly, we learn that pathogenesis is a step by step development of a disease and the events which leads to the disease. 2 types of infection, acute- displays all symptoms and chronic- only some symptoms. If infected, 90% of infants and 50% of young children will be chronically infected and only 5% to about 10% of immuno-competent ( able to produce normal immune response ) adults will be infected with HBV develop chronic hepatitis B.
Acute infection normally be will from subclinical ( not so serious ) to fulminant ( very severe ). Symptoms such as loss of appetite, nausea, fever, abdominal pain and jaundice will occur. 90% to 95% of acutely infected adults recover without sequelae ( pathological condition resulting from a disease ) and 5% to 10% will become chronically infected.
Whereas for chronic infection, patients who are still potentially infectious, have no symptoms and no abnormalities are called the chronic carrier state.Some will have chronic hepatitis and others will develop cirrhosis followed by hepatocellular carcinoma which is liver cancer. If worse, death.
I have also drawn a flowchart to summarise the above.
*Click flowchart below for better view.
What are the lab diagnosis for this virus?
> Detectable serum hepatitis B surface antigen ( HBsAg )
> Diagnosis of HBV infection made on serology (diagnostic identification of antibodies in serum)
> HBeAg ( enveloped antigen )detectable in acute infection which is characterized by a high rate of viral replication
> igM ( recently infected by diease ) antibodies against core antifen are detectable
> igG ( will always be present after infected ) antibodies against core are produced
>When acute infection resolves, igG antibodies stays and igM antibodies and HBsAg will become undetectable
> People who had acute infection that resolves will have igG antibodies against core antigen for life whereas those who do not clear HBV will continue to have serum HBsAg
> After diagnosis of hepatitis B is confirmed, prognosis ( doctor’s view of how a patient will
progress ) assessed by liver biopsy ( test involving the removal of tissues or cells for examination )The hepdnavirus is transmitted through blood and sexual contact. Sexual behaviour and consuming drugs are to be avoided to avoid getting infected.