Hillary Norton, MD, discusses the diagnosis of axial spondyloarthritis, namely the difficulties of accurate and timely identification, and considers possible comorbidities.
Hillary Norton, MD: The signs and symptoms of axSpA that are very important to recognize really involve a distinction between mechanical and inflammatory back pain. Inflammatory back pain starts under the age of 35, lasts for at least 3 months, and involves pain that is worse at night, generally in the second half of the night. The pain improves with exercise and worsens with rest and generally responds very well to NSAIDs [nonsteroidal anti-inflammatory drugs].
Part of the diagnostic tests that we use involve checking for HLA-B 27, because over 90% of axSpA patients—of all different genetic backgrounds—are going to have HLA-B 27. Additionally, we will do x-rays of the FI joints, and if nothing is seen on x-ray that is definitive, then we will proceed to using MRI [magnetic resonance imaging]. It is important to remember that in women, symptoms can present higher up in the spine, in the thoracic spine and the cervical spine, early in disease.
We know that there’s a substantial delay in diagnosis. Many studies tell us that it’s often up to 10 years still. Part of the reason for this is the lack of general awareness about this disease. Many people have not heard of axSpA or AS yet. And so in this day, when patients look up information prior to going in to be seen for a referral, they just don’t know what they’re looking for.
Some of the comorbidities and extra articular manifestations that we see with axSpA include inflammatory bowel disease, uveitis, and psoriasis. Rarely do patients have cardiac and pulmonary involvement. So it’s important that we do a thorough history and physical and make sure that we are checking the skin, that we are asking questions about inflammatory bowel disease, and making sure that patients are aware of the warning signs of uveitis.
There’s a lot of work being done to increase recognition of axSpA on many levels. Recognition in the general public is where it all needs to start, but there is a lot of education directed toward other kinds of providers that may be seeing these patients. They’re often seen in sports medicine clinics, physical therapy clinics, neurosurgery, orthopedics, primary care. So we are reaching out to these different specialties to organize a concerted effort to get these patients into rheumatology.
There’s a difference in the pathophysiology of the joint damage between, say, rheumatoid arthritis and ankylosing spondylitis. Both of them can start with boney erosions, but rheumatoid arthritis will end there; whereas in ankylosing spondylitis there will be repair of the bone that leads to new bone formation. In the spine this can lead to syndesmophytes initially and then to actually boney bridging of the spine leading to the bamboo spine.