What is Enthesitis?
Enthesitis is inflammation of the entheses – the point where ligaments or tendons insert into the bone. Also called enthesopathy, doctors will use the terms ‘enthesitis’ and ‘enthesopathy’ interchangeably, though technically the term ‘itis’ refers to inflammation of the entheses.
Enthesitis commonly occurs in patients with a form of inflammatory arthritis – particularly the seronegative spondyloarthropies, including Ankylosing Spondylitis and Psoriatic Arthritis. It also occurs in Rheumatoid Arthritis, but is less common.
In the absence of an inflammatory arthritis, enthesitis is usually caused by an injury or overuse.
Symptoms of Enthesitis
Enthesitis is often a very painful condition. Symptoms may include pain, stiffness, tenderness at the insertion site and swelling. Sometimes, however, there are no visible signs making it a difficult condition to diagnose via physical examination alone.
Imaging can help make the diagnosis, MRI is preferred for the axial skeleton, while ultrasound is most often used for peripheral joints.
Sites affected by Enthesitis
Enthesitis most often affects:
- Feet/heels, especially the Achilles tendon
- The plantar fascia
- Facet joints that connect the spine’s vertebrae
- Sacroiliac joint (most commonly in Ankylosing Spondylitis)
Fingers and toes can also be affected, and even the chest wall can become inflamed making deep breaths difficult.
Treatment of Enthesitis
Because enthesitis is most often caused by an underlying inflammatory arthritis, treatment is directed at the underlying disease. Treatment options will depend on the severity of the condition, and include a combination of exercise, physiotherapy and medication.
Medications include NSAIDS (non-steroidal anti-inflammatory drugs) e.g. ibuprofen, naproxen or mobic. DMARDs (Disease Modifying Anti Rheumatics) e.g methotrexate also assist by controlling the underlying disease processes. TNF inhibitors have been shown to be effective.
Local corticosteroid injections can be useful to quickly calm down the inflamed entheses if oral medications aren’t fully effective.