What causes appendicitis

What is the Appendix?

The appendix is a small, tube-shaped pouch of tissue connected to the large intestine (colon) at the junction where the small intestine joins the colon. Although its exact function remains unclear, the appendix may play a minor role in immune function. The appendix is typically 3-4 inches long and about the diameter of a pencil. Despite its small size, when it becomes inflamed, it causes a serious medical condition requiring immediate treatment.

Primary Cause: Blockage

The most common cause of appendicitis is a blockage inside the appendix. This obstruction prevents normal drainage of fluids and bacteria from accumulating in the appendiceal lumen. The blockage can result from several sources:

• Hardened stool (fecoliths) that accumulates and hardens inside the appendix
• Swollen lymphoid tissue from viral or bacterial infection
• Foreign objects accidentally ingested
• Tumors, though these are rare
• Thickened intestinal secretions

Bacterial Infection and Inflammation

Once the appendix becomes blocked, bacteria normally present in the colon multiply rapidly within the appendix. This bacterial overgrowth triggers inflammation of the appendiceal wall. The inflamed tissue swells and fills with pus, causing increasing pressure and pain. This inflammatory response is what causes the characteristic symptoms of appendicitis, including severe abdominal pain and fever.

Secondary Factors

While blockage is the primary mechanism, other factors can contribute to appendicitis development. Inflammatory bowel disease increases appendicitis risk. Cystic fibrosis patients show higher incidence rates, possibly due to thicker secretions. Trauma to the abdomen may occasionally trigger inflammation. Certain infections, particularly viral infections affecting the lymphoid tissue, can increase risk by causing tissue swelling.

Risk Factors and Demographics

Appendicitis can develop at any age but most commonly affects people between ages 10 and 30. Males are slightly more likely to develop the condition than females. Having a family history of appendicitis may increase risk. Geographic and dietary factors may also play roles, though these remain incompletely understood.

Complications from Untreated Appendicitis

Without treatment, appendicitis progresses and can cause severe complications. If the inflamed appendix ruptures, bacteria spill into the abdominal cavity causing peritonitis, a life-threatening abdominal infection. The patient can develop sepsis and organ failure without emergency surgery. This is why appendicitis requires immediate medical evaluation and typically emergency appendectomy.