Causes

• Obstruction of the appendiceal lumen usually precipitates appendicitis.
• The most common causes of luminal obstruction are fecaliths and lymphoid follicle hyperplasia.
• Fecaliths form when calcium salts and fecal debris become layered around a nidus of inspissated fecal material located within the appendix.
• Lymphoid hyperplasia is associated with a variety of inflammatory and infectious disorders including Crohn disease, gastroenteritis, amebiasis, respiratory infections, measles, and mononucleosis.
• Obstruction of the appendiceal lumen has less commonly been associated with parasites (eg, Schistosomes species, Strongyloides species), foreign material (eg, shotgun pellet, intrauterine device, tongue stud, activated charcoal), tuberculosis, and tumors.