Ankylosing Spondylitis

Welcome back to the Viking Blog! For the next few installments, we're going to look at the condition ankylosing spondylitis.

 First, we'll define this medical condition and the populations most affected, and describe the signs and symptoms. Next week, we'll see what tests and examinations are used to diagnose the condition and evaluate a patient's prognosis. Finally, we'll take a look at how ankylosing spondylitis is treated, and we'll explore the way it affects a person's ability to exercise, as well as how exercise might benefit a person living with this condition.

 We'll start by breaking down the words that make up the name of the condition, which in this case is a combination of terms that derive from Greek. Let's look at it backwards.

• Spondyl- is based upon the Greek word “spondylos,” which means vertebra – the many bones that stack upon one another to make up the spine.
• The suffix -itis indicates inflammation. So, when we combine the two halves, we end up with the word “spondylitis,” or inflamed vertebra.
• “Ankylosing” further describes the type of/result of the inflammation. It is based on the Greek word “ankylos” which can mean bent, crooked, in the form of a loop, and/or adhesion.

Understanding this gives us a vivid idea of what this condition might be like, before we even get to the clinical definition of ankylosing spondylitis.

With that information in mind, let's dig deeper into this condition. Ankylosing spondylitis is a variety of arthritis (arthro = joint + itis = joint inflammation) that primarily affects the spinal column. The bones of the spine (vertebrae) become inflamed and rub against one another, causing erosion and further inflammation. Although we may not think of it as such, bone is living tissue, and in this particular disease process, it may attempt to compensate for the damage by overgrowing. As these bony overgrowths develop, the spine becomes less flexible and distorted from its normal curvature. The new growth may end up creating a bridge to adjacent vertebrae and thus fusing.

Because ankylosing spondylitis is a chronic condition, this process tends to continue and can eventually result in large areas of the spine becoming totally fused, or in extreme cases, the entire spinal column may fuse, which is described as a “bamboo spine.” Frequently, the process of inflammatory damage and overgrowth begins at the joint where the lower spine or sacrum meets with the top of the pelvis or ileum, known as the sacroiliac joint, and progresses up the spine. In some patients, the process is discontinuous, rather than steadily ascending the spinal column.

The same process may also occur in other joints, such as the hips, shoulders, ribs, and along the back of the heel, causing stiffness, pain, bone erosion and overgrowth, and eventual fusion. When this occurs in the ribcage, the joints between the ribs and their attachments to the spine and the sternum become inflexible. This compromises the person's ability to breathe normally, by limiting the expansion and contraction of the ribcage and diminishing lung capacity, which may be exacerbated by abnormal curvature of the spine.      

Osteoporosis commonly occurs alongside ankylosing spondylitis, which complicates the condition by adding the risk of compression fractures in the vertebrae, which in turn can create more pressure on the spinal cord, nerves, and intervertebral discs. Fractures further destabilize the spine and can lead to more arthritic inflammation in unfused vertebrae.

Less often, the inflammation may present as uveitis which affects the lens of the eye, causing pain, blurred vision, photosensitivity, and redness, often with rapid onset. The risk of heart disease is increased, and in rare cases, the inflammation affects the cardiovascular system by distorting the aorta where it meets the heart's aortic valve.  

According to the Johns Hopkins Arthritis Center, it is diagnosed approximately twice as often in men as in women, and it tends to present during a patient's 20s or 30s. While symptoms can start in a patient's teens or in their 40s or 50s, symptoms begin under the age of 30 for ~80% of patients. A range of symptoms can occur, but most patients initially present with lower back and/or hip pain and stiffness. The pain and stiffness tend to be worst in the morning and during the latter half of a night's sleep, and are alleviated somewhat by movement. If fusions have occurred, the spine may curve abnormally and posture may be stooped. Other areas of the skeleton can be involved as described above, as well as organs such as the heart, eyes, lungs, skin, and the gastrointestinal tract.

Since many of these symptoms also occur in other serious medical conditions, it is important to seek medical care to determine whether ankylosing spondylitis or some other malady is to blame. Additionally, since the condition is both chronic and degenerative, early diagnosis and intervention are critical. Thank you for reading, and please come back to the blog next Tuesday for part two, where we will delve into the tests that are used to reach a diagnosis.