Ankylosing Spondylitis (AS) and Why You Should Care
For the next 4-5 years I will be studying the pathogenic mechanisms of Ankylosing Spondylitis (AS). My goal is to develop a deep understanding about what brings about AS, how does AS start? How does AS progress? What do the symptoms of AS look like? What are the factors involved in AS progression, and severity? What are some potential therapies out there that can mitigate clinical symptoms, slow down disease progression or cure the disease.
Ankylosing Spondylitis is an inflammatory arthritis affecting primarily the axial skeletal (spine) and to a degree the peripheral skeletal (every other bone) causing patients’ severe pain, reduces mobility and greatly affects the quality of life. AS is characterized by inflammation, bone erosion in the early stages of the disease, and new bone growth in the later stages.
Bone erosion is mainly seen in the entheses in the spine between the vertebrae disks; the pints as which ligaments and tendons connect to the bones.
Patients with long term AS exhibit the out growth of bony spur (syndesmophytes) causing adjacent vertebral bodies to fuse together into a single piece causing the spine to stiffen up in what is called “bamboo spine.” Bone fusion results in a hunched-forward posture appearing as if they are always bending forward. Spinal fusion is observed in the lower back, more commonly at the sacroiliac joints, the joint that connects the spinal cord to the hip bone.
Signs and Symptoms include joint and lower back pain than can last for years or be lifelong. Compared to other forms of arthritis, pain associated with AS occurs at night, causing sleep disturbances and extreme mornings stiffness, but improves through the day with increasing physical activity.
Other symptoms include anorexia, malaise, lower grade fever, weight loss, and fatigue.
Other manifestation of the disease that are not associated with the bone includes, anterior uveitis, Inflammatory bowel disease (IBD), subclinical inflammation of the gut as well as cardiac and respiratory abnormalities.
AS is present in about 0.1% of the general population and is more common in men than in women. While to some this may not seem like a lot, 0.1% of the global population is a lot of people. Age of onset is estimated to be between the age of 26-30 but before 40 years of age. It is not known what causes AS, but risk factors include genetic and environmental factors which implicates nature and nurture in the onset progression and severity of the AS.
Why should you care?. There are more than 200 distinct rheumatic diseases and they are one of the oldest and most characterized diseases, yet we still do not have a cure. Current treatment merely reduces symptoms and slows down disease progression, but a cure is still lacking. Classification, characterization and diagnosis is difficult because for most, we do not fully understand how they start or what is causing them. They account for a large percentage of disabilities world wide with social and economic burden but even more importantly, they reduce an individual’s quality of life
Gabriel, S. E., & Michaud, K. (2009). Epidemiological studies in incidence, prevalence, mortality, and comorbidity of the rheumatic diseases. Arthritis Research & Therapy, 11(3), 229. http://doi.org/10.1186/ar2669
Stolwijk, C., Boonen, A., van Tubergen, A., & Reveille, J. D. (2012). Epidemiology of Spondyloarthritis. Rheumatic Diseases Clinics of North America, 38(3), 441–476. http://doi.org/10.1016/j.rdc.2012.09.003