<aside> 💡 Acute inflammation of the appendix, typically due to an obstruction of the appendiceal lumen.

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Uncomplicated: no evidence of an appendiceal fecalith, an appendiceal tumour or complication such as perforation, gangrene, abscess or mass

Complicated: associated with perforation, gangrene, abscess, an inflammatory mass, an appendiceal fecalith or an appendiceal tumour

Demographics

• Young adults, males most common

Aetiology

luminal obstruction by:

• Lymphoid tissue hyperplasia (60%): most common in young adults / children
• Appendiceal fecalith and faecal stasis (35%): most common in adults
• Neoplasm (uncommon): more likely in patients >50yo (carcinoid tumour)
• Parasitic infestation (uncommon): e.g. Ascaris lumbricoides, Taenia, Schistosoma, Enterobius vermicularis
• Undigested materials (seeds, gum)

Pathophysiology

• Obstructed appendiceal lumen
  • Stasis of mucosal secretions → bacterial multiplication and local inflammation → transmural spread of infections
  • increased intraluminal pressure → obstruction of veins → oedema of appendiceal walls → obstruction of capillaries → ischemia → gangrenous appendicitis +/- perforation
• Inflammation can spread to serosa → peritonitis

Clinical Presentation