( Michael S. Singer M.D. Ph.D. Co...)Appendicitis: Evolving Tools to Diagnose a Classic Disease,Health

Appendicitis is a common, potentially lethal condition that affects 7% of individuals sometime in their lives. The condition occurs when the appendix, a blind pouch of intestine at the proximal colon, becomes obstructed by mucus, stool, or lymphatic tissue. Infection ensues, which can rapidly evolve to perforation and sepsis. The risk of these complications, already elevated for children and those over 50, rises as appendectomy is delayed. To compound the problem, numerous diseases mimic appendicitis, and it is often difficult to rule it out based on clinical presentation. This is due to well-known variance in history and physical exam. For example, the classic symptoms of abdominal pain, nausea, and loss of appetite have minimal if any predictive value for appendicitis versus other abdominal conditions. Clinicians fail to appreciate appendicitis on presentation in 25-30% of children.

Uncertainty often remains even after physical exam. The classic finding of right lower quadrant tenderness is present in some 96% of appendicitis patients but also in many other conditions. No feature on physical exam has been proven to rule out appendicitis definitively. Fortunately, a number of laboratory and imaging modalities, some new and sophisticated, can improve levels of clinical confidence. Ideally, these tools should provide optimal positive predictive value to facilitate early appendectomy, all in an effort to reduce mortality rates (which can reach 1%). They should also provide optimal ,i>negative predictive value to rule out appendicitis with confidence and avoid unnecessary surgery.

Clinicians invariably order laboratory studies in cases of suspected appendicitis, where an elevated white blood cell count (WBC) is a classic but nonspecific feature. Only 80-85% of patients with appendicitis, however, have a WBC over 10K. A study with
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