How does diagnosis go wrong?
Misdiagnosis can occur in two directions. Firstly, the doctor may conclude incorrectly that a patient does not have a condition to which a diagnostic label should be attached, or for which treatment is needed, and hence allow undiagnosed symptoms to persist, such as gastro-oesophageal reflux causing non-cardiac chest pain or chronic cough. Conversely, the doctor may confer a formal diagnosis on the patients symptoms, despite the absence of adequate evidence of a recognisable medical disorder, such as making a diagnosis of vertebrobasilar insufficiency in a patient with vague unsteadiness. A sense of pressure to make a specific diagnosis can come from patients, from fear of litigation if a disease is missed,11 or from the expected role of general practitioners as identifiers of disease.12
Wrong diagnoses in primary care can be caused by atypical and non-specific presentations, very rare conditions, and comorbidity, and also perceptual factors such as failure to observe subtle changes in colour or contour or abnormal swellings13 or gradual changes over time, as sometimes happens with patients with hypothyroidism or acromegaly. Other causes are shown in the box.
