If left untreated, appendicitis will often get progressively worse as the inflammation leads to further complications.
Pressure within the appendix will increase, limiting the amount of blood flowing through the walls of the appendix, where the tissue then becomes starved of blood and starts to die.
Eventually, the appendix will rupture, leaking its contents throughout the abdomen. In some cases, abscesses (pockets of pus) may form on the ruptured appendix; if the abscesses tear, they can infect the rest of the abdomen, which is extremely dangerous and potentially fatal.