Appendicitis

Appendicitis is inflammation of the appendix, a narrow tube, closed at one end and several centimeters long, that hangs from the cecum, the first part of the large intestine, in the lower right abdomen. It can occur at any age but is most common in the teens and twenties, and it is the leading cause of sudden abdominal pain that needs an operation.

It usually begins when the opening of the appendix is blocked, most often by swollen lymphoid tissue in its wall and sometimes by a hardened pellet of stool called a fecalith. Mucus and bacteria build up, the appendix swells, its blood supply fails and its wall can die and burst, spreading infection through the abdomen (peritonitis) or forming an abscess. Typically a dull pain near the navel shifts over a few hours to the lower right abdomen, with poor appetite, nausea and a low fever, but young children, older adults and pregnant women often have less typical symptoms.

Diagnosis rests on the history and examination, helped by blood tests showing a raised white cell count and by ultrasound or CT. The usual treatment is appendectomy, removal of the appendix, most often by laparoscopy, together with antibiotics. Some mild cases settle with antibiotics alone, although the inflammation may come back.