Once an inflamed appendix perforates or becomes gangrenous the morbidity of acute operative management increases. Oliak et al used CT scanning to identify patients with a perforated or gangrenous appendix who might benefit from initial nonoperative management. The authors are from Harbor-UCLA Medical Center in Torrance, California.


Key findings on CT scan associated with perforation:

(1) extraluminal gas

(2) abscess

(3) phlegmon

(4) terminal ileal wall thickening


The individual findings have good specificity (88-100%) but poor sensitivity (24-75%). The authors therefore combined the first 3 findings to generate the following rule:


If one or more of the following (extraluminal gas, abscess, phlegmon) is present, then the patient is managed as for perforated or gangrenous appendicitis.


Performance (Table 4, page 961):

• The sensitivity of the combined rule was 92% with a specificity of 88%.

• The positive predictive value is 96% but the negative predictive value is 74% (2 false positive vs 5 false negative in series).


To read more or access our algorithms and calculators, please log in or register.