Appendicitis is an acute inflammation of the appendix, a small pouch attached to the large intestine. It commonly occurs due to blockage of the appendiceal lumen by fecal matter, lymphoid hyperplasia, infection, or, rarely, tumors. Typical symptoms include abdominal pain that initially starts around the navel and later shifts to the lower right side of the abdomen, loss of appetite, nausea, vomiting, fever, and abdominal tenderness. If left untreated, the inflamed appendix may rupture, leading to peritonitis, abscess formation, and potentially life-threatening complications.