learning to stay vigilant about conditions that are rare but important

All doctors who look after children need to recognise the presentation of Kawasaki disease: theconsequences of missing it are potentially drastic for the affected child. The question is how we reinforce our undergraduate learning about rare but important conditions. Many years in practice without seeing a case may erode the vigilance of the generalist who has many common and important conditions jostling for priority as learning needs in continuing medical education.

In the rapid responses, Christopher Martin draws attention to context, rightly drawing on Loong's recent paper1 to remind us that, in practice, even cardinal symptoms have low predictive values if the incidence of the condition is very low. Martin drawsattention to the tendency for case reports to focus on rarities. Is this a bad thing? Is there a place for an educational counterbalance to the everyday experience that “common things occur commonly” and to any implicit assumption in family practice that “it's a virus until proved otherwise”?

The thoughtful contributions from around the world emphasise that specialists too have some cause to reflect when it comes down to the details of managing uncommon conditions, as David Burgner pointed out. Questions that arose included:

• Does the benefit of aspirin to a child with suspected Kawasaki disease outweigh the risk of Reye's syndrome?

• Does the neutrophilia justify blood cultures, lumbar puncture, or broad spectrum antibiotics, although the fever is abating?

• Are immunoglobulins effective after more than 15 days?

These are all good examples of questions for evidence based practice, and the discussion on bmj.com and the expert commentaries are designed to promote just such reflection on practice for those who engage actively with our cases. All innovations in medical education need to be evaluated, and in evaluating these interactive case discussions we will have to look at whether expert commentaries promote or stifle readers' readiness to search the evidence base.