[et2o]

This is a pretty stupid example imo, it isn't really workable in practice. You can die from a ruptured appendix and the surgery isn't terribly involved. Whereas people come in constantly with elevated WBCs; it'd require a high index of suspicion to treat for appendicitis with antibiotics in every circumstance. You would probably end up doing more harm than good that way because antibiotics are not benign drugs.

[sandworm101]

The WBC count would only be some evidence. I presume some sort of ultrasound could localize the infection in the appendix.

I imagine there are some people for whom surgery isn't an option. I'm not sure what that condition might be given the routine nature of the procedure, but they might be out there.

[et2o]

I'm sorry, I shouldn't have called it stupid, that was needlessly inflammatory.

Basically my point is that most people where you could diagnose appendicitis from elevated WBCs followed by ultrasound will probably not be in the hospital or clinic or ED in the first place. The reason this is a surgical emergency is because the symptoms are of rapid onset. Thus, elevated WBCs are of limited utility. Furthermore, because appendicitis is an emergency, ultrasound is not the preferred imaging modality–CT scans are used instead, which are relatively more expensive and expose patients to ionizing radiation.

You can choose to treat patients with antibiotics (and they've done studies), but generally over 50% of patients managed initially with antibiotics will ultimately require surgery anyway within 48 hours, and of the <50% that don't, there is a relatively high recurrence rate that will ultimately also require surgery. Given that appendectomy has a very low morbidity and mortality, this is one of the surgeries that are harder to argue against in my opinion.

From my reading of Uptodate, experts in the field feel similarly; after performing a cost/benefit analysis, initial management with antibiotics is indicated only for patients who cannot undergo surgery.