Hepatitis, meaning like this inflammation, of the liver, most commonly comes about because of a virus.
These viruses tend to target the cells in the liver, and when they get in and infect these cells, they tend to cause them to present these weird and abnormal proteins via their MHC class 1 molecules, and at the same time, you’ve also got these immune cells infiltrating the liver and trying to figure out what’s going on, and so the CD8 positive T cells recognize these abnormal proteins as a sign that the cells are pretty much toast, and the hepatocytes go through cytotoxic killing by the T cells and apoptosis.
Hepatocytes undergoing apoptosis are sometimes referred to as Councilman bodies, shown on histology here, and this typically takes place in the portal tracts and lobules of the liver.
This cytotoxic killing of hepatocytes is the main mechanism behind inflammation of the liver, and eventual liver damage in viral hepatitis!
As someone’s hepatitis progresses, we’ll see a couple classic symptoms related to your immune system mounting an attack, like fever, malaise, and nausea.
Additionally though, patients might have hepatomegaly, where their liver is abnormally large from inflammation, which might cause some pain.
Also, as more and more damage is done to the liver, the amount of transaminases in their blood will increase.
Your liver has these transaminase enzymes so it can do its job of breaking down various amino acids.
Typically the serum amino transaminase, or the amount in your blood, is pretty low, but when your hepatocytes start getting damaged they start leaking these into the blood, so a common sign is a greater amount of both alanine aminotransferase, or ALT, and aspartate aminotransferase, or AST, typically even though both are elevated, ALT will be greater than AST in viral hepatitis and will also be the last of the two liver enzymes to return to normal.