Work related upper limb disorders

Neuropathic arm pain (NAP), commonly referred to as 'RSI', diffuse upper limb disorder or type II work related upper limb disorder (WRULD) is a regional pain syndrome affecting the upper limb(s), characterized by persistent pain and dysaesthesiae. It is commonly associated with long periods of keyboard use, though may also occur in workers engaged in other types of repetitive stereotyped activities of the hands. Adverse ergonomics is commonly present. Sleep pattern is usually disturbed, and depression, headaches, chronic fatigue, and frustration are frequently experienced. The pathogenesis of NAP is probably linked to overloading of sensorineural mechanisms responsible for pain production and perception. Clinical findings include muscle tension and hyperalgesia in the upper limbs and shoulder girdles, adverse neural dynamics, and frequently (and importantly) proximal dorsal spinal dysfunction. Other factors that are often associated with the development of neurosensitisation include premorbid psychological profile, environmental stresses, misattributions and beliefs, adverse posture and ergonomics, iatrogenesis, and litigation. Conventional investigations such as cervicodorsal spinal radiographs, nerve conduction studies, and MRI are negative. Clinical management is structured on reduction of provocative stresses and treatment of neuromusculoskeletal dysfunction. The differential diagnosis is discussed in this article.