HHE Rheumatology 2019 | Page 17

RHEUMATOLOGY Managing bone and joint infections in rheumatological disease This review aims to highlight and address the challenges in presentation, investigation and management of septic arthritis and vertebral osteomyelitis in adults treated with biologic therapies Georgina Beckley MBBS MRCP FRCPath Elizabeth Darley MBChB MRCP FRCPath MD North Bristol NHS Trust, Bristol, UK Bone and joint infections are an important cause of morbidity and mortality worldwide, particularly in those with inflammatory arthritis. In the US, the prevalence of septic arthritis is 2–10/100,000 but rises to 30–70/100,000 in patients with rheumatoid arthritis. Patients with underlying rheumatological conditions are at an increased risk of infection due to existing abnormal joints (in the case of inflammatory arthritis), as well as immunosuppressive therapies. The British Biologics Register data shows that the risk of patients with rheumatoid arthritis developing septic arthritis doubles in patients treated with biologic therapy compared with non-biologic therapy. 1 Overlapping symptoms A history of pain, swelling and fever as well as classical symptoms of infection could also be due to the patient’s underlying inflammatory arthritis. This can lead to a delay in diagnosis. Even in patients without underlying rheumatological disease, the delay in diagnosis can range from two weeks to nine months. 2 A rheumatological flare may affect several joints; however, if only a sterile joint is aspirated for microscopy and culture this could then lead to a missed infected joint elsewhere. Clinical manifestations The classical signs and symptoms of bone and joint infection are joint pain, fever and swelling. Presentation of bone and joint infections in patients with rheumatological conditions can be variable and more indolent. Correct diagnosis and management can therefore require a higher index of suspicion. Immunosuppressed state The other consideration is that both the use of immunosuppressive agents and the underlying inflammatory arthritis can alter the response of the immune system to infection. This makes patients more prone to acquiring an infection; but also once an infection has occurred, can make the symptoms and signs more insidious. 17 HHE 2019 | hospitalhealthcare.com There are two major challenges: overlapping symptoms and an immunosuppressed state.