heuristics

Cognitive bias is increasingly recognised as an important source of medical error, and is both ubiquitous across clinical practice yet incompletely understood. This increasing awareness of bias has resulted in a surge in clinical and psychological research in the area and development of various ‘debiasing strategies’. This paper describes the potential origins of bias based on ‘dual process thinking’, discusses and illustrates a number of the important biases that occur in clinical practice, and considers potential strategies that might be used to mitigate their effect.

Diagnosis can prove challenging when a patient with a chronic neurological disease presents with acute deterioration. This is especially true in Huntington's disease, where cognitive impairment is prominent. We present a case of hypercalcaemia causing an acute deterioration in physical and cognitive function in a patient with Huntington’s disease. Similarity in clinical phenotype between hypercalcaemia and Huntington’s disease, as well as failure to appreciate the acute nature of the deterioration resulted in diagnostic delay and prolonged admission.