Ankylosing spondylitis (AS) usually affects the joints of the spine, but it can also affect other joints especially the hips. AS can also occasionally cause inflammation of the eyes, chest wall, heart, and lungs. If this inflammation does not get treated, it will eventually lead to scarring and permanent damage. Some people have a mild form of this disease, others are unfortunate enough to have the aggressive form. This disease may or may not get worse, depending upon several factors. These factors include, how old you were when the disease began, what joints are affected, and how early you got a correct diagnosis. Unfortunately there is no cure as of yet.

Doctors are not sure of the cause for AS, but they do know that genetics plays a part in the disease. Around 95% of patients diagnosed with this disease have a gene which produces a genetic marker, HLA-B27. However, having this gene does not mean a person is sure to get the disease. There is only about a 40% chance of developing AS if you have this gene. Also, you do not have to have this gene in order to develop AS. Many people have the HLA-B27 producing gene, around or below 25% of the population depending on the country, but only between 1% and 5% of people actually develop ankylosing spondylitis.

There is current research going on to determine the causes of the inflammation that is part of ankylosing spondylitis. Some researchers believe this inflammation begins with a bacterial infection that causes the immune system to react. Once the bacterial infection is gone, a normal person's immune system reverts to 'protect and scan' mode, but in a person affected by AS their immune system stays in the 'attack' mode. This causes tissues to become inflamed. Other researchers think that AS begins when the intestinal defenses break down, causing bacteria to get into the bloodstream, and then to the joints most affected by this arthritis, the sacroiliac joints.

The most common symptom of AS is one many people are familiar with, lower back pain and/or stiffness. This symptom can present as early as adolescence which causes many people with ankylosing spondylitis to be mis-diagnosed as teenagers with a sports related injury. The pain and stiffness are often gradual, which means many people don't tell their doctor about the pain.

The pain and stiffness are caused by the inflammation of the spine, which if not treated can lead to a fusing of the vertebrae or ankylosis. Once this happens, the pain disappears, as does mobility in the spine. The ankylosis can cause a forward curving of the chest area, which decreases breathing capacity. This fusion can also extend to the rib cage, causing ribs to fuse to the spine, decreasing lung capacity. Other symptoms of AS are arthritis in other joints (usually the hips, knees, and ankles) and inflammation of the cartilage surrounding the breast bone, eyes, kidneys, and the heart.

A correct diagnosis of AS can be difficult to receive. Early symptoms can often be caused by other, more common diseases. It is especially difficult to diagnose in women because they usually have less involvement of the spine, usually but not always. A patient may have to live with the pain for several years before ankylosing spondylitis is even considered.

The tests for AS are actually pretty simple. They include the usual medical history and physical exam, then the doctor will order an x-ray of the spine and a blood test for the HLA-B27 marker. The physical exam may show preliminary signs such as limited mobility of the spine, decreased breathing capacity, and eye inflammation. The spine x-ray will show if fusion of the vertebrae has already occurred.

Once correctly diagnosed, treatment begins. Treatment includes the taking of non-steroid anti-inflammatory drugs (NSAIDs), physical therapy and then increased exercise. The NSAIDs reduce the inflammation, and pain, of the affected joints which can increase mobility. In patients where other joints, such as the knees, hips and ankles, are inflamed, the NSAIDs may not work very well. If that happens, there are other drugs that can be used such as sulfasalazine and methotrexate. Methotrexate is more effective than sulfasalazine but it is potentially toxic to the liver and bone marrow. Patients undergoing methotrexate treatment must have frequent blood tests to determine if either of these organs are being damaged.

With increased mobility comes the physical therapy and exercise to improve posture and increase mobility and breathing capacity. All exercise regiments need to be approved by a doctor so the patient does not unintentionally harm him/herself.