Perforation of Appendicitis

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.

Some authors have questioned whether some perforations in acute appendicitis are attributable to delay in diagnosis after a patient seeks medical attention. Velanovich and Satava postulated a surgeon’s misdiagnosis rate (the percentage of normal appendixes found at appendectomy) to be inversely related to the perforation rate (the percentage of perforated appendixes found at laparotomy). They believed that surgeons are obliged to operate quickly when appendicitis is suspected, thus minimizing the likelihood of perforation in exchange for a higher rate of misdiagnosis. More recent studies suggest that this reasoning is flawed. Temple and colleagues showed that patients with perforated appendicitis were operated on more quickly than those with nonperforated appendicitis (6.5 hours versus 9 hours), but perforated patients had significantly longer prehospital symptoms (57 hours versus 22 hours).These findings are confirmed by two other studies, both showing that longer duration of prehospital delay is the major contributor to perforation.Perforation after presenting to surgical attention appears to be uncommon.

When acute appendicitis has progressed to appendiceal perforation, other symptoms may be present. Patients will often complain of two or more days of abdominal pain, but their duration of symptoms may be shorter, as previously discussed. The pain usually localizes to the right lower quadrant if the perforation has been walled off by surrounding intra-abdominal structures including the omentum, but it may be diffuse if generalized peritonitis ensues. The pain may be so severe that patients do not remember the antecedent colicky pain. Patients with perforation often have rigors and high fevers to 102°F (38.9°C) or above. A history of poor oral intake and dehydration may also be present.

Most patients with perforated appendicitis present with symptoms related to the inflamed appendix itself or to a localized intraperitoneal abscess from perforation. Other more rare presentations do occur, however. These are most likely to occur in the very young and very old, who cannot express their symptoms and often present late in the course of their disease. For instance, abscesses can also form in the retroperitoneum due to perforation of a retrocecal appendix, or in the liver from hematogenous spread of infection through the portal venous system. An intraperitoneal abscess could fistulize to the skin, resulting in an enterocutaneous fistula. Pylephlebitis (septic portal vein thrombosis) presents with high fevers and jaundice and can be confused with cholangitis; it is a dreaded complication of acute appendicitis and carries a high mortality.Occasionally, patients will have bilious vomiting and obstipation due to a small bowel obstruction resulting from appendiceal perforation. Because appendicitis is so common, these rare presentations should alert the surgeon to the possibility of appendicitis.