Assessment of chronic pain – history
It is helpful to consider chronic pain as a disease in which many factors – physical, pathological and psychosocial – contribute to the presentation. Thus the history itself is more than the history of the symptoms which provide diagnostic clues, the traditional model on which medical science is based. The clinician taking a history of chronic pain must be prepared to set aside preconceptions on which traditional medical diagnosis is taught. For example, standard teaching may suggest that pain that is experienced in a ‘glove’ or ‘stocking’ distribution is in some way ‘fraudulent’ because it does not fit with a preconceived anatomical knowledge of the sensory dermatomes. From the perspective of the pain clinic, symptoms of pain should be recorded as they are experienced, without prejudice to the clinician’s view of the mechanisms involved. Contributing psychosocial factors need to be noted, with the understanding that they are likely to be present, and in a way that the patient is not blamed for the presentation. Most importantly, since the aim of management of chronic pain is a reduction in disability and return of function, the history must include factors such as the impact of the pain on normal functioning. To achieve this the context of history taking is wide: patients, self-rating questionnaires, pain diagrams and diaries and the perspective of relatives all offer further information. Discussion of the pain with the patient allows psychological signs to be manifest. Although a diagnosis is less sought after in the pain clinic than in other settings, pathology better managed in other clinics has to be excluded. Traditional medical teaching identifies so-called screening ‘red flags’ in presentation of illness that mandate the focused search for serious pathology such as cancer or inflammatory disease. Pain clinic history taking uses an analogous screening technique for elements in the psychosocial presentation. We will refer to them as ‘yellow flags’ to distinguish them from the ‘red flags’: they are not life-threatening symptoms, but their presence means that the psychosocial history has to be clearly focused. They are symptoms that may need addressing in their own right with psychological treatments.