Acute Appendicitis

Appendicitis begins as a closed-loop obstruction

The appendix is a blind-ending tube. When its lumen is blocked (usually by a faecolith, sometimes by lymphoid hyperplasia after a viral illness or, rarely, a tumour), mucus and bacteria continue to be secreted into a space that cannot drain. Pressure inside the lumen rises steadily because nothing can escape, exactly as in any closed loop of bowel. That rising intraluminal pressure is the single event from which the rest of the disease follows.