Ankylosing Spondylitis is one of the more common forms of arthritis affecting about 0.5% of the population. It affects men more often than women in a ratio of about 2.4-5:1. The disease is categorized as a "spondyloarthropathy"... a type of arthritis that preferentially affects the spine. It usually starts in the sacroiliac joints- the joints that join the pelvis to the low back- and spreads upwards to involve the rest of the spine. Peak age of onset is between 15 and 30 years.
Typically, a patient will complain of stiffness in the low back or neck or both that is worse with rest and better with activity. Often, a young person will pursue sports as a way to relieve the pain they have! Stiffness during the day after inactivity is also common. Other joints affected include the hip, knee, wrists, shoulders, elbows, and ankles. Typically, patients will have not only joint symptoms but they will also have enthesopathy... meaning inflammation at points where tendons connect to bones. Fatigue is a very common symptom. Occasionally low grade fever, appetite loss, and weight loss may be seen.
Patients will sometimes present with the extra-articular (outside of the joint) symptoms. Examples include inflammation of the eye, lungs, and rarely, the heart. The most common extra-articular symptom is eye inflammation which occurs in about 40% of patients and must be diagnosed and treated aggressively. Blindness is a dreaded complication.
The physical exam will show limitation of range of motion in the low back. Chest expansion is also restricted since many patients with AS will have limited ability to expand their lungs due to involvement of the thoracic spine.
Occasionally, women with AS will have more symptoms in the neck than the low back.
Laboratory testing will show abnormalities that indicate the presence of inflammation. Patients with AS will also have the genetic marker HLA B27 in about 90% of cases.
Imaging studies such as magnetic resonance imaging will show the presence of inflammation in the sacroiliac joints. Inflammation of the tendon insertions at different affected joints will also be evident.
Treatment goals consist of relieving pain and stiffness as well as maintaining function.
A comprehensive program consists of a combination of anti-inflammatory medicines to help with symptoms as well as disease-modifying therapy to slow down the rate of progression. Examples of anti-inflammatory drugs are drugs such as ibuprofen (Motrin), naproxen (Naprosys), nabumetone (Relafen), etodolac (Lodine), meloxicam (Mobic), and Celecoxib (Celebrex). Disease-modifying drugs that are used extensively for this condition are sulfasalazine (Azulfidine) and methotrexate. Biologic therapies like etanercept (Enbrel), adalimumab (Humnira), and infliximab (Remcade) are considered important for inducing remission. A solid program of physical therapy to help with range of motion is also mandatory.
For patients with suspected eye disease, close supervision by an experienced ophthalmologist is also recommended.
Patients with far-advanced disease may suffer complications including compression of the spinal cord (cauda equina syndrome), and fractures of the neck. In particular, care should be exercised in preparing patients with AS for surgery. Intubation (placing a breathing tube into the airways) for general anesthesia carries the risk of inadvertent spine fracture.
Surgery is reserved for far advanced cases that have not responded to medical therapy.
The clinical course and prognosis is highly variable and also highly dependent on the rapidity of diagnosis and the effectiveness of therapy.
Dr. Wei (pronounced "way") is a board-certified rheumatologist and Clinical Director of the nationally respected Arthritis and Osteoporosis Center of Maryland. He is a Clinical Assistant Professor of Medicine at the University of Maryland School of Medicine and has served as a consultant to the Arthritis Branch of the National Institutes of Health. He is a Fellow of the American College of Rheumatology and the American College of Physicians. For more information on arthritis and related conditions, go to: Types of Arthritis
