Enthesitis Definition

An x-ray like image of an inflamed sacroiliac joint.
An x-ray like image of an inflamed sacroiliac joint.. SCIEPRO / Science Photo Library / Getty Images

Enthesitis Definition

Enthesitis is inflammation of soft tissue (muscle, ligament or tendon) right where it inserts into the bone. It is associated with arthritis and is one of the main signs of spondyloarthritis. Enthesitis is also associated with DISH, a disease in which spinal ligaments harden.

Enthesitis often causes the affected area of the soft tissue to become ropey (called fibrosis) and/or solid (called calcification or ossification).

It can be quite painful; the pain occurs mainly when, as you use your muscles, they pull on the bones.

Although it is not universally present in arthritis, enthesitis is often a characteristic feature in spondyloarthritis, which is one type of inflammatory arthritis.

With inflammatory arthritis, enthesitis is often found at the sacroiliac joints.  It is considered to be an active inflammatory lesion, and in fact, the primary lesion of spondyloarthritis (inflammatory arthritis) according to a study published in the 2006 issue of the journal Best Practice and Research Clinical Rheumatology. The authors say that enthesitis may also involve synovitis and other types of active inflammation.

For people with spondylitis, an MRI using one of several specialized techniques is used to find evidence of enthesitis and other active inflammatory lesions. Enthesitis is most often diagnosed by history and physical exam alone.

Medications given for enthesitis are aimed at either reducing inflammation or suppressing the immune system. They include NSAIDs, prednisone (a corticosteroid), methotrexate, (a cancer drug) and sulfasalazine (a drug often given for rheumatoid arthritis). Another class of medication are TNF blockers (also called biologics.)  TNF blockers not only reduce inflammation but are also able to stop disease progression, according to the American College of Rheumatology.

Sources:

D'Agostino, M., Olivieri, A. Enthesitis.Best Pract Res Clin Rheumatol. June 2006 Accessed: March 2016. http://www.ncbi.nlm.nih.gov/pubmed/16777577

Anti-TNF Drugs. American College of Rheumatology website. March 2015. Accessed: March 2016. http://www.rheumatology.org/I-Am-A/Patient-Caregiver/Treatments/Anti-TNF

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