What Three Wise Men have to say about diagnosis

Most clinicians will be familiar with Occam’s razor, a guiding principle that is interpreted as “the simplest explanation is to be preferred.” In relation to medical diagnosis this is taken to mean that when a patient has multiple symptoms and signs, a single diagnosis should be sought that accounts for all the clinical features rather than attributing a different diagnosis to each.

To what extent should we rely on Occam’s wisdom? All clinicians can recall patients who have not conformed to this principle, and over reliance on it has the potential for misdiagnosis. Accurate diagnosis underpins good clinical practice; figures suggest that rates of diagnostic errors in the emergency department setting are as high as 10-15%1 and that misdiagnosis is responsible for around 10% of adverse events in hospitals.2 With this in mind, we present examples for and against the use of Occam’s razor from our area of interest: head and neck oncology, the management of which provides a good template to study these diagnostic dilemmas. Most patients undergo imaging of distant sites at diagnosis, and spread to the regional lymph nodes usually occurs in a predictable pattern before distant metastases. We also examine the views of other “wise men” who have proposed principles that caution against over reliance on Occam.