Obstruction of the lumen Mucus accumulates in the lumen, intraluminal pressure increases Bacteria convert mucus into pus Obstruction of the lymphatic drainage ensues- edema of the appendix, beginning diapedesis of the bacteria and appearance of mucosal ulcers Venous obstruction & further edema & ischemia in the appendix Symptoms: o Poorly localized visceral pain – periumbilical or epigastric o Anorexia o Nausea & vomiting o (small bowel and appendix have the same nerve supply)

Bacterial invasion spreads thru the wall of the appendixCompromise of the arterial blood supply Midportion of the antimesenteric border undergoes gangrene with the appearance of the ellipsoidal infarcts Excape of bacteria from the lumen of the appendix and contamination of the peritoneal cavity Cntinued high intraluminal pressure – perforation thru gangrenous infarct, spilling accumulated pus lead to local and then generalized peritonitis Inflammatory site is bordered from abdominal cavity – appendiceal phlegmon develops Symptoms: o Inflamed serosa of the appendix contacts the parietal peritoneum – somatic pain – perceived as classic shift and localization of pain in RLQ o Fever o Tachycardia o Leukocytosis o Muscle defence o Positive Blumberg sign

Typical clinical manifestation in % of patients Possible diagnostic pitfalls Negative appendectomy rate up to 25-45%

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