Appendicitis

Appendicitis is the inflammation of the appendix, a small, tube-shaped pouch that extends from the cecum, the first part of the large intestine.

It often begins with blockage of the appendiceal lumen by fecaliths, tumors, lymphoid hyperplasia, parasites, or foreign bodies.

The blockage prevents normal mucosal drainage, allowing secretions to accumulate and pressure to build within the appendix.

Swelling and pressure within the appendix decrease effective arterial blood flow, resulting in appendiceal ischemia. The reduced oxygen supply weakens the mucosal lining, leading to ulceration.

The compromised mucosal barrier allows gut bacteria, such as E. coli and Bacteroides, to invade the appendiceal wall, leading to infection.

The immune system responds with acute inflammation—neutrophils infiltrate, and the appendix swells and fills with purulent fluid, a process that may start at the tip but often spreads throughout the entire organ.

As inflammation worsens, rising pressure impairs blood flow, leading to ischemia, tissue death, and eventually gangrene.