How to investigate: Chronic pain.

Chronic pain is defined as an unpleasant sensory and emotional experience persisting longer than the normal process of healing, usually longer than 3 months. About a fifth of the world's population is believed to suffer from chronic pain. In Europe, chronic pain accounts for nearly 500 m lost working days, and it costs the European economy >€34 billion (£28 billion) every year. Establishing a reliable diagnosis is the primary challenge in evaluating a patient with chronic pain. Common diagnoses not to miss include seronegative spondyloarthritides, endocrine abnormalities including severe vitamin D deficiency and polymyalgia rheumatica. Once important or treatable diagnoses have been ruled out, the history can be used as a tool to establish a therapeutic plan for shared decision-making using the biopsychosocial model. Onward referral to pain clinics can be helpful for more involved patient management, but often good outcomes are achieved with the support of primary care.