[1: Clinical aspects, laboratory diagnosis and therapy. Low backache--when is sacroiliitis the cause?].

Despite the availability of modern imaging modalities, early diagnosis of sacroiliitis remains a challenge. The patient's history and the results of the clinical examination form the basis for establishing a working diagnosis, which then needs to be confirmed by laboratory tests and diagnostic imaging. Common causes of sacroiliitis are inflammatory diseases of the spine, in particular seronegative spondyloarthropathies; infectious sacroiliitis is much less common. Besides serological testing (HLA-B27), imaging techniques are essential for diagnosing early forms of sacroiliitis. The treatment of the condition initially involves the use of non-steroidal anti-inflammatory drugs (NSAIDs). In patients with infectious sacroiliitis, antibiotics are the treatment of choice. Local application of steroids, or physiotherapy, can be helpful. The value of disease-modifying drugs (DMARDs) (sulfasalazine, methotrexate) has not been verified, and is questionable. New approaches such as anti-tumor necrosis factor alpha (anti-TNF alpha) need to be tested in controlled studies.