Common and external iliac artery occlusion in Behçet's disease: a case of anchoring bias

This report describes the case of a 45-year-old woman with a history of Behçet's disease and complex regional pain syndrome of her legs who presented with severe pain and swelling in her left lower extremity. The patient was initially diagnosed with exacerbation of complex regional pain syndrome, which fit the symptom complex of hyperalgesia, oedema and skin temperature changes. However, after unsuccessful attempts at significant pain relief during admission, CT angiography demonstrated occlusion of the left common and external iliac arteries, a limb-threatening emergency. This case describes an example of anchoring bias, a type of cognitive bias in which there is a tendency to rely too heavily on an initial piece of information, the 'anchor', when making decisions. This report emphasises that clinicians should be aware of biases when making decisions and avoid anchoring bias by asking themselves if their diagnosis is influenced by any leading pieces of information.