The lower backbone is called the lumbar spine is made of a stack of 5 block-like bones called vertebrae with a triangular bone attached underneath. These bones are separated by oval cushions called discs. The tip of the triangular bone is the tailbone, or coccyx. The large hip bones on each side under the buttocks attach to the sides of the lowest triangular bone and are called the sacroiliac joints.
If ankylosing spondylitis is present there may be damage to these joints or the spine. This leads to stiffness and in severe cases the spinal bones fuse together. The entire spine and sometimes other joints in the arms and legs are involved. There may be inflammation in the eyes, the cervix in women, and penis in men. Sometimes inflammation in these areas is seen in people with a skin disease called psoriasis and in others with inflammation of the colon called colitis.
If the disease occurs mainly in the spine, it is called ankylosing spondylitis. If there is psoriasis present, then it may be called psoriatic arthritis. Crohn’s disease and ulcerative colitis are types of colitis which may cause arthritis in the spine and other joints. In many cases a blood test for a gene named HLA-B27 is positive, especially in ankylosing spondylitis. Inflammation in the sacroiliac joints is called sacroiliitis.
The symptoms of low back pain due to inflammation are different in several important ways, but especially in how long the stiffness lasts, several hours to all day. Also, the stiffness tends to worsen after a period of rest or sleep. The worst stiffness is usually in the morning. This is different than other more common causes of low back pain where the extra morning stiffness is usually no more than thirty to sixty minutes. It may be difficult to expand the chest when taking a deep breath, as the rib joints to the spine may be involved.
A physical examination and x-rays by an arthritis specialist called a rheumatologist may confirm ankylosing spondylitis is present.
Very successful treatment now is available for patients with ankylosing spondylitis. Newer medications reduce inflammation and improve pain, stiffness, function, and quality of life when the disease is treated. The FDA has approved several medications called “TNF inhibitors” for the treatment of ankylosing spondylitis (Enbrel, Humira, Remicade and Simponi). Usually rheumatologists are asked to help provide care for this form of arthritis.