What is the presumed cause of appendicitis in adults or children?
Intestinal concretions around fecal matter, or fecaliths (in adults) or hypertrophied lymphoid tissue causing obstruction of the lumen (in children), are the dominant etiologic factors. Fecaliths are found in approximately 90% of cases of gangrenous, ruptured appendicitis. The luminal obstruction causes distention of the appendix from both continued mucosal secretion and local bacterial overgrowth. Ultimately, venous pressure is exceeded and areas of wall infarction with bacterial invasion occur.