Effect and treatment of chronic pain in inflammatory arthritis

Abstract

Pain is the most common reason patients with inflammatory arthritis see a rheumatologist. Patients consistently rate pain as one of their highest priorities, and pain is the single most important determinant of patient global assessment of disease activity. Although pain is commonly interpreted as a marker of inflammation, the correlation between pain intensity and measures of peripheral inflammation is imperfect. The prevalence of chronic, non-inflammatory pain syndromes such as fibromyalgia is higher among patients with inflammatory arthritis than in the general population. Inflammatory arthritis patients with fibromyalgia have higher measures of disease activity and lower quality of life than inflammatory patients who do not have fibromyalgia. This review article focuses on current literature involving the effects of pain on disease assessment and quality of life for patients with inflammatory arthritis. It also reviews non-pharmacologic and pharmacologic options for treatment of pain for patients with inflammatory arthritis, focusing on the implications of comorbidities and concurrent disease-modifying antirheumatic drug therapy. Although several studies have examined the effects of reducing inflammation for patients with inflammatory arthritis, very few clinical trials have examined the safety and efficacy of treatment directed specifically towards pain pathways. Most studies have been small, have focused on rheumatoid arthritis or mixed populations (e.g., rheumatoid arthritis plus osteoarthritis), and have been at high risk of bias. Larger, longitudinal studies are needed to examine the mechanisms of pain in inflammatory arthritis and to determine the safety and efficacy of analgesic medications in this specific patient population.

Fig. 1

Central pain regulatory mechanisms may mediate pain sensitivity in inflammatory arthritis via loss of conditioned pain modulation and/or central sensitization. Loss of conditioned pain modulation occurs when the descending analgesic pathways are absent or attenuated. Central sensitization occurs as a result of enhanced glutamate sensitivity