Ankylosing spondylitis may be the most common disease you’ve never heard of—not to mention the true cause of your low-back pain.
More than 2.7 million people—including Dan Reynolds, a multi-platinum, Grammy Award-winning recording artist and lead singer of Imagine Dragons—live with the pain and stiffness of an inflammatory form of arthritis in the spine. It’s called ankylosing spondylitis or AS (pronounced ank-kih-low-sing spon-dill-eye-tiss), and it’s an autoimmune disease: This means that your own immune system attacks healthy tissues; in the case of AS, the target is your lower spine. Low back pain and stiffness are the hallmarks of AS, but they may not be the first or the only symptoms you experience. “AS is not an easy diagnosis in many patients since the onset can be gradual and symptoms subtle,” says David Stephen Pisetsky, MD, PhD, a professor of Medicine, Rheumatology, and Immunology at Duke University Medical Center in Durham, North Carolina. “The diagnosis is often missed and symptoms ascribed to other causes.” There are clues that can help you and your doctor make an AS diagnosis. They include:
Sign: Your back pain persists
When you overdo it at the gym and pull a muscle, your back will usually complain and remain stiff for a few days or a week before clearing up on its own. That’s not the case with AS. The pain tends to involve the sacroiliac (SI) joints at the base of your spine (where your spine meets your pelvis) and usually lasts for at least three months, according to the Spondylitis Association of America. There may be quiet periods with little to no pain that are followed by flares when AS symptoms get more intense and new problems appear.
Sign: Your stiffness
People with AS are extremely stiff like the Tin Man in the Wizard of Oz, explains Suleman Bhana, MD, a rheumatologist in Middletown, New York. For the launch of a new AS awareness campaign, Monster Pain in the AS, Dr. Bhana also pointed out that the stiffness usually starts in the lower back and buttocks and can spread up the spine and into the neck. “Stiffness is usually worse during the morning,” he says.
Sign: Your other joints ache too
Your spine isn’t the only joint AS will target: Other joints such as your hips, ankles, elbows, knees, shoulders, fingers, and even jaw may suffer. “With AS, the joint involvement is not symmetrical like it is with rheumatoid arthritis and lupus,” he says. “It may be one ankle and not the other, or two fingers on one hand and none on your other hand,” Dr. Bhana explains. Not all types of arthritis are alike.
Sign: Your stooped-over posture
AS can force your spine to fuse into a fixed, hunched position. “One of the first things a rheumatologist will do is measure your spine and neck to better track the disease process,” Dr. Bhana says. Early diagnosis and treatment can hopefully prevent this fusion from occurring in the first place.
Sign: Your blood work
AS is an inflammatory disease so if you have it, you’ll likely have markers of inflammation in your blood. These include C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). If these markers are elevated it tells your doctor that your body is fighting inflammation, but it doesn’t provide much more detail. There are many non-AS related reasons for high CRP or ESR. But “if there is no measurable inflammation in your blood, your back pain is likely not a result of AS,” Dr. Bhana says.