False Positives and Unintended Consequences

After an appendectomy, the removed appendix is examined to determine whether appendicitis (or some other problem) was present. In a noticeable proportion of people, it is not. This is not a problem, for a good reason: the consequences of untreated appendicitis can be swift and catastrophic. The consequences of appendectomy are, in general, mild by comparison, at least in societies with good sanitation. (There is always risk from surgery.)

This is being revised after trials with intravenous antibiotics have shown very high rates of survival, but appendectomy was introduced before the antibiotic era, many organisms are involved, and we’re losing antibiotic efficacy – plus appendicitis can still progress after IV therapy – so surgery still needs to be in the toolkit. Still, knowing that there are options well worth trying, and with a good track record, is good news for situations where surgery may not be available, practical, or advisable.

[T]ypes of patients in whom appendectomy might be avoided:

  • Patients with an appendiceal abscess, who would be better treated with percutaneous drainage;
  • Patients who have had a recent myocardial infarct;
  • Patients with severe lung disease;
  • Women in the first trimester of pregnancy; and
  • Persons in a remote environment such as Antarctica or on a mission to Mars.

From Evaluating Acute Appendicitis: Does Everyone Need an Operation? (subscription required)

(Mars – or the Antarctic – is hardly the only remote environment of interest; one of the studies was in Navy personnel on a submarine.)

Appendectomy is a classic teaching case on the value of ending up with a few false positives. It’s better to perform a low-complication procedure a few extra times than to have people walking out of the ER and dying when they get home. But as technology changes – in this case, antibiotic treatment options and CT-scan evaluation – it’s always good to re-evaluate even the obvious “tried and true” approaches, partly to see if there’s a better way across the board and also to address the situations where the outcome of surgery was likely to be bad. On the way, we seem to have discovered some properties of the appendix that can help us understand the environment for other GI disease – a new teaching case for this much-maligned “vestigial” organ!

We are probably right to remain suspicious, though. The appendix may well have more tricks tucked into its submucosa.

Leave a Reply

Your email address will not be published.