Sacroiliitis (say-kroe-il-e-I-tis) is an inflammation of one or both of your sacroiliac joints — the places where your lower spine and pelvis connect. Sacroiliitis can cause pain in your buttocks or lower back, and may even extend down one or both legs. The pain associated with sacroiliitis is often aggravated by prolonged standing or by stair climbing.
Sacroiliitis can be difficult to diagnose, because it may be mistaken for other causes of low back pain. It’s been linked to a group of diseases that cause inflammatory arthritis of the spine. Treatment of sacroiliitis may involve a combination of rest, physical therapy and medications.
A wide range of factors or events may cause sacroiliac joint dysfunction, including:
- Traumatic injury. A sudden impact, such as a motor vehicle accident or a fall, can damage your sacroiliac joints.
- Arthritis. Wear-and-tear arthritis (osteoarthritis) can occur in sacroiliac joints, as can ankylosing spondylitis — a type of inflammatory arthritis that affects the spine.
- Pregnancy. The sacroiliac joints must loosen and stretch to accommodate childbirth. The added weight and altered gait during pregnancy can cause additional stress on these joints and can lead to abnormal wear.
- Infection. In rare cases, the sacroiliac joint can become infected.
The pain associated with sacroiliitis most commonly occurs in the buttocks and lower back. It can also affect the legs, groin and even the feet. Sacroiliitis pain can be aggravated by:
- Prolonged standing
- Bearing more weight on one leg than the other
- Stair climbing
- Taking large strides