Abstract

Diagnostic reasoning relies on cognitive heuristics to recognise patterns of symptoms and signs in order to arrive at a diagnosis. These rules of thumb allow us to rapidly diagnose common conditions that present in typical ways. However, they may lead us astray when common conditions present atypically or when a patient has a rare condition or multiple conditions causing their constellation of symptoms, signs, and test results, rather than having a single diagnosis to explain them all. This article describes strategies to help counteract diagnostic pitfalls, to expand diagnostic possibilities and to make diagnostic progress with complex, multielement cases.