The introduction of biological disease-modifying drugs (DMARDs) has substantially improved the treatment options for patients with rheumatoid arthritis. However, infectious complications represent the most common side effects of these drugs, including severe infections as well as rare opportunistic infections. Treating patients on biological DMARDs is therefore one of the biggest challenges in rheumatology care. The present review describes the current state of knowledge regarding frequency and type of infectious complications associated with biological DMARDs. The article focuses mainly on risk management, in particular on diagnosis and recurrence prevention of tuberculosis and reactivation of hepatitis B virus infection. Furthermore, we discuss the importance of vaccinations in primary disease prevention in patients with rheumatoid arthritis.

The differential diagnosis of inflammatory arthritis of the hip covers a broad spectrum and includes in particular crystal arthropathies and systemic rheumatic diseases. The clinical examination of joint effusion of the hip may be difficult but diagnostic ultrasound should support an early diagnosis. Radiographs remain essential in the initial diagnostic evaluation but may be of limited value in early stages of the disease. Magnet resonance imaging may be helpful in addition for the detection of early arthritis.Basic laboratory diagnostics include blood count, determination of C-reactive protein level and erythrocyte sedimentation rate. If septic arthritis is suspected blood cultures should be taken. Joint aspiration should be attempted in all cases and especially in monoarthritis. Synovial fluid analysis includes white cell count, differential count, examination for crystals and microbiological diagnostics including direct stains and cultures. The most important differential diagnoses of inflammatory arthritis of the hip joint in adults are osteoarthritis, crystal arthropathies and systemic rheumatic diseases, such as spondyloarthritis.