It is a commonly held belief that if left untreated, appendiceal inflammation will progress inevitably to necrosis, and ultimately to perforation. The time course of this progression varies among patients. In one study of the natural history of appendicitis, the authors questioned patients undergoing appendectomy for suspected appendicitis about their duration of symptoms. Patients with nonperforated appendicitis reported an average of 22 hours of symptoms prior to presentation to the hospital, while patients with perforated appendicitis reported an average of 57 hours. However, 20% of cases of perforated appendicitis presented within 24 hours of the onset of symptoms; one of those patients had symptoms for only 11 hours. Although concern for perforation should be present when evaluating a patient with more than 24 hours of symptoms, the clinician must remember that perforation can develop more rapidly.
Delay in seeking medical care appears to be the principal reason for perforations; the appendicitis has just been allowed to progress according to its natural history. Perforation is accompanied by more severe pain and higher fever (average, 38.3 °C) than in appendicitis. It is unusual for the acutely inflamed appendix to perforate within the first 12 hours. The appendicitis has progressed to perforation by the time of appendectomy in about 50% of patients under age 10 or over age 50. Nearly all deaths occur in the latter group.
The acute consequences of perforation vary from generalized peritonitis to formation of a tiny abscess that may not appreciably alter the symptoms and signs of appendicitis. Perforation in young women increases the subsequent risk of tubal infertility about fourfold.