Appendicitis is primarily caused by a blockage inside the appendix, which leads to inflammation and infection. This blockage can be due to several factors:
- Hardened stool or fecal deposits called fecaliths or appendicoliths, which are calcified "stones" made of feces, are the most common cause of obstruction
- Swelling of lymphoid tissue in the appendix wall, often triggered by viral infections, can also block the appendix
- Other causes include infections by bacteria, viruses, parasites, or fungi in the digestive tract that cause swelling and inflammation
- Rarely, tumors or foreign bodies (such as undigested seeds or nuts) can block the appendix
- Inflammation of nearby intestines (such as colitis) or enlarged lymph nodes can contribute to blockage and infection
When the appendix is blocked, mucus builds up inside, increasing pressure and cutting off blood flow. This leads to swelling, bacterial overgrowth, tissue damage, and potentially rupture, which can cause serious complications like peritonitis and sepsis
. Risk factors include a low-fiber diet, which may promote fecal stasis and fecalith formation, and possibly genetic predisposition, although appendicitis itself is not inherited
. In summary, appendicitis is caused by obstruction of the appendix lumen-most commonly by fecaliths or lymphoid swelling-leading to infection and inflammation
