Arthritis and pain. Current approaches in the treatment of arthritic pain

Abstract

Current evidence suggests that although persistent arthritic pain is initiated and maintained by articular pathology, it is also heavily influenced by a range of other factors. Strategies for treating arthritic pain are therefore different from those adopted for acute pain. Although published guidelines offer general assistance, the complexity of underlying mechanisms requires that measures designed to relieve pain must take into account individual biological, psychological and societal factors. It follows that a combination of both pharmacological and non-pharmacological approaches offers the best opportunity for therapeutic success, although determining the effectiveness of such complex interventions remains difficult. Pharmacological therapy is often prolonged, and safety and tolerability issues become as important as efficacy over time.

Figure 1

Classification of pain. Nociceptive pain is triggered by tissue injury and activates unmodified nociceptive neurons (light arrow) inducing acute pain. In contrast, normally innocuous stimuli produce pain in neuropathic and neuroplastic conditions in consequence of sensitized nociceptive pathways (dark arrows). Note: Idiopathic pain omitted from figure. (Adapted from [3].)

Figure 2

Causes and consequences of neural plasticity. Although tissue injury or inflammation can trigger nociceptor sensitization in peripheral neurons (1), other somatic, psychological and environmental influences are likely to determine the magnitude of any subsequent change as a result of modulation of activity at spinal (2) or cortical (3) levels. (Adapted from [3].)

Figure 3

Principles for the management of osteoarthritis: a suggested sequential pyramidal approach to symptom management. (Adapted from [49].)

Figure 4

Oxford league table of commonly used analgesics in acute pain. Numbers needed to treat for 50% pain relief over 4 to 6 hours are shown. Note that no comparable data exist for analgesia for chronic musculoskeletal pain. (Adapted from [50].)

Figure 5

Multimodal therapy for the management of arthritic pain with a mechanism-based approach. Note the lack of a hierarchical system with potential for synergistic interactions between therapeutic options in different boxes.