The appendix is a rather boring, small piece of the gut. About 2-3 inches long it is blind ended, hollow and has no known function, apart from causing trouble. It sits on the end of the large intestine, close byl where the small intestine joins the caecum. More detail

Appendicitis is the condition that results when the appendix gets inflamed for whatever reason. More detail

The appendix gets infected and inflamed filling up with pus. Left untreated it will burst causing peritonitis. As the appendix becomes inflamed it causes pain, initially a cramping central pain that later becomes much sharper and more severe as it spreads and settles low down on the right hand side. There is usually some vomiting and a fever. More detail

Initially the symptoms are very non-specific and can be easily confused with various other conditions . As time goes by and the situation progresses it becomes easier to diagnose with certainty. Sadly by then it is a much more serious condition. More detail

Appendicitis must be treated by surgically removing the inflamed appendix before it bursts.  If it does burst internally, or is burst during surgery then the infected matter spreads throughout the abdomen causing peritonitis. This is a very serious condition frequently resulting in death even with the best treatment. If peritonitis does develop then surgery is still required to remove the ruptured appendix and to physicvally clean as much of the infection out of the abdomen as possible. This must be coupled with very high dose antibiotics to try to overcome the infection. More detail