The natural history and traditional management of appendicitis revisited: Spontaneous resolution and predominance of prehospital perforations imply that a correct diagnosis is more important than an early diagnosis

Background: The principle of early exploration on wide indications in order to prevent perforation has been the guiding star for the management of patients with suspected appendicitis for over 100 years, dating back to a time when appendicitis was a significant cause of mortality. Since then there has been a dramatic decrease in mortality due to appendicitis. Emerging evidence calls for a new understanding of the natural history of untreated appendicitis. This motivates a reappraisal of the fundamental principles for the management of patients with suspected appendicitis. Methods: Analysis of epidemiologic and clinical studies that elucidate the natural history of appendicitis, i.e. the possibility of spontaneous resolution or the risk of progression to perforation, the determinants of the proportion of perforations and mortality, and the consequence of inhospital delay. Results: The results presented in a number of studies suggest that spontaneous resolution of appendicitis is common, that perforation can seldom be prevented, that the risk of perforation has been exaggerated and that in-hospital delay is safe. An alternative understanding of the inverse relationship between the proportion of negative explorations and perforation and the increasing proportion of perforation with length of time is presented, mainly explaining these findings by selection due to spontaneous resolution. Conclusion: Evidence suggests that spontaneous resolution of untreated, non-perforated appendicitis is common and that perforation can rarely be prevented and is associated with a lower increase in mortality than was previously thought. This motivates a shift in focus from the prevention of perforation to the early detection and treatment of advanced appendicitis. In order to minimize mortality, morbidity and costs avoidance of negative appendectomies is more important then preventing perforation. In patients with an equivocal diagnosis where advanced appendicitis is deemed less likely a correct diagnosis is more important than a rapid diagnosis. These patients can safely be managed by active observation with an improved diagnostic work-up under observation, which has consistently shown a low proportion of negative appendectomies without an increase in the proportion of perforations or morbidity. A high proportion of perforations can be explained by selection due to undiagnosed resolving appendicitis. The proportion of perforation is therefore a questionable measure of the quality of the management of patients with suspected appendicitis and should be used with caution.