Painful inflammation of the SI joint can be a symptom of a range of inflammatory conditions.
- Traumatic injury
- Repeated stress on the SI joints from repetitive movements
- Misaligned or malformed joints
Sacroiliitis is typically the first symptom of ankylosing spondylitis (AS). Ankylosing spondylitis originates in the sacroiliac joints before progressing further up the spine through a cycle of inflammation, erosion, and calcification.
Accurate diagnosis of ankylosing spondylitis requires the sacroiliac joints to be visibly affected by this inflammation cycle. Detection and diagnosis of ankylosing spondylitis-related sacroiliitis can be achieved through X-ray imaging, MRI scans, and/or CT scans paired with blood tests to detect elevated C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR).
Psoriatic arthritis (PsA) is an inflammatory condition that causes joint pain and swelling as well as scaly skin patches, called psoriasis.
Psoriatic arthritis can be difficult to differentiate from rheumatoid arthritis.1 However, psoriatic arthritis is more likely to cause spondylitis, the inflammation of the spinal joints, including the SI joints.2 If sacroiliitis is among the symptoms experienced by a patient, psoriatic arthritis is the more likely diagnosis.
Experts estimate about 10% of people with psoriasis develop psoriatic arthritis. The majority of people with psoriasis, about 90%, do not experience joint pain and swelling.
Gout is caused by a buildup of uric acid crystals in a joint. The most common form of inflammatory arthritis, gout typically affects one joint at a time—most often the big toe. However, gout patients may experience pain and inflammation of the SI joints as well.3
If typical gout treatments are ineffective against SI joint symptoms (and no additional inflammatory conditions can be identified by a physician), direct treatment of the SI joints may be necessary. Treatment of gout-related SI joint inflammation includes a diagnostic injection of anesthetic to confirm the source of pain and a steroid compound to treat the gout flare.
See Gout Treatment
As discussed in this article, there are many possible causes of SI joint inflammation. Effectively treating sacroiliitis begins by treating the underlying cause of the SI joint inflammation.
Non-Arthritic Causes of SI Joint Pain
Not all SI joint pain is related to arthritis. Trauma, pregnancy, and mechanical stresses can also lead to painful symptoms.
- Trauma. The SI joint or the ligaments supporting and surrounding the SI joint can be injured by trauma. The trauma may or may not seem severe. For example, SI joint injury can come from something as simple as stepping on a stair or curb the wrong way and “jamming” the joint to sustaining a fall or even being in a motor vehicle accident.
- Lax ligaments during pregnancy. During pregnancy, the hormones relaxin and progesterone relax the muscles and ligaments, particularly in the pelvis. Occasionally the ligaments get too lax that the SI joint slips out of place and can be painful. Symptoms often lessen or go away after pregnancy is over and the ligament becomes stronger.
- Mechanical stress. Some people have severe stiffness in their spines due to conditions such as severe arthritis or surgical spinal fusion. This stiffness can cause additional stress at the SI joint, which over time can lead to degenerative changes and pain.
A health care professional can diagnose the root cause of SI joint pain and help devise a treatment plan.
Treatment of Sacroiliac Dysfunction
Most causes of back pain that relate to SI dysfunction can be treated with rest of the joint, anti-inflammatory medication, and physical therapy. When SI joint pain and sacroiliitis are caused by a type of arthritis, the underlying condition must be diagnosed and treated.
Occasionally the irritated SI joint is slightly "out of place" and a physical therapist can realign the joint through exercise and manipulation. Sometimes injections can be used to help address the inflammation and occasionally surgical treatment is needed for cases of SI dysfunction that don't respond to non-operative treatment.