• The mucosa on the left is totally necrotic and infiltrated by polys in contrast to the normal viable mucosa on the right which shows no necrosis or infiltrate

•The presumed etiology is obstruction, most commonly a fecalith; with parasites seen in other parts of the world

•Currently, less than half of the cases with acute appendicitis have a fecalith, and in these lymphoid hyperplasia, secondary to viral or bacterial infection is implicated

•Obstruction is thought to lead to increased intraluminal pressure due to continued secretion of fluids

•Increased intraluminal pressure eventually exceeds intravenous pressure leading to stoppage in venous flow and ischemia

•Ischemic damage leads to bacterial invasion of the mucosa with ischemic and septic necrosis

•Predominantly a disease of the Western world, presumed related to lower dietary fiber

•Incidence is decreasing due to changes in dietary fiber

•All ages affected with peak incidence in 2nd and 3rd decade

•Males/Females 1.6/1.

•Sequence of symptoms: abdominal pain; nausea, vomiting, and anorexia; pain localizes over appendix, fever

•Patient is seen and diagnosis usually made 1 to 2 days after onset of pain

•Laboratory findings are those of acute inflammation and infection

•Treatment is appendectomy

• Surgery is curative and mortality approaches 0.0 in the non-perforated patient.With perforation mortality is <1.0% except in the elderly where it is higher

•Early-edema and telangiectasia of serosal vessels

•Later-Dilated lumen, thickened wall, dusky discoloration of serosa, fibrinous or fibrinopurulent serosal exudate

•Late-Mucosal necrosis often with hemorrhage, gangrenous softening of wall, heavy coating of purulent exudate on the serosa

•With complications such as perforation or abscess formation, the appendix may appear gangrenous and be found in a walled off collection of pus

•An intraluminal obstruction, most commonly a fecalith, is found in 30 to 50% of cases

•Early-neutrophil infiltrate of lumen, mucosa and muscularis

•Later-Mucosal necrosis, fibrinopurulent exudate on serosa

•Late-Extensive necrosis of mucosa and muscularis, with microabscesses within the appendiceal wall

• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 823-824

• Rosai J: Ackerman^s Surgical Pathology. 8th ed. St. Louis, Mosby-YearBook, 1996, pp. 711-716

• Current literature from PubMed at National Library of Medicine