Abstract

There has been a long-standing belief that both rheumatoid arthritis and other types of inflammatory arthritis may be a consequence, either directly or indirectly, of infection. Although there is no evidence of a single organism or group of organisms responsible for a significant proportion of otherwise idiopathic cases, there are still increasing and intriguing reports of inflammatory arthritis following several viral, bacterial and other infecting microorganisms.

More importantly, patients with rheumatoid arthritis and related diseases are at an increased risk of infection independent of their drug treatment, which in its turn can cause the arthritis to worsen. There are attempts to develop risk scores to predict which patients are more likely to develop a serious infection but their value in clinical practice is uncertain. Much work has shown a number of immunological biomarkers are risk indicators and these data need to be pursued.

The greatest interest in infections has resulted from concerns following the introduction of biological agents with their pathway blocking activity in reducing inflammation, also enhancing the risk of potentially serious infections. Reactivation of TB infection following TNF monoclonal use is well known but with the increasing use of these agents, there are more case reports of infections with unusual organisms. Such reports do help guide clinicians when attempting to diagnose an unknown infection in a recently treated patient. Currently much interest is centred on the less well-documented data on use of drugs such as Abatacept, Anakinra, Tociluzimab and Rituximab, as well as the newer agents that are likely to receive their license in the near future.