Given the serious nature of ankylosing spondylitis, these authors review common signs and symptoms, offer pertinent diagnostic insights and discuss the available treatment options for managing this condition.

Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects the costovertebral, sacroiliac and the apophyseal joints as well as the surrounding tissues. Ankylosing spondylitis is more frequent among men between the ages of 20 and 40. The disease, which is also referred to as rheumatoid spondylitis and Marie Strumpell disease, affects 129 of every 100,000 people in the United States, according to estimates from the Mayo Clinic. The frequency of the condition is approximately 0.1 to 0.2 percent of the population in the U.S., as well as internationally.



While the actual cause of the disease is unknown, researchers have identified a genetic component and there is an increased prevalence of HLA-27 among Caucasians and HLA-B7 in the African-American population. There is also an increased prevalence in members of a family who have ankylosing spondylitis. American Indians have the highest prevalence of this disease in the U.S.

Primary care practitioners should be able to recognize, evaluate and initiate treatment for those patients suffering from ankylosing spondylitis, and make the appropriate rheumatology referral when indicated. Accordingly, let us take a closer look at the diagnosis and management of this condition.

When evaluating a patient for the possibility of ankylosing spondylitis, clinicians must rule out a variety of conditions. One should be able to rule out rheumatoid arthritis of the spine and herniated intervertebral disks early in the evaluation. Other conditions in the differential diagnosis include but are not limited to gout, psoriatic arthritis and Reiter’s Syndrome.

When seeing older patients, one must consider diffuse idiopathic skeletal hyperostosis (DISH) syndrome, a condition that clinicians will usually see among males over the age of 50. Be aware that this condition can mimic ankylosing spondylitis both clinically and radiologically. However, in regard to patients with DISH, the sacroiliac and spinal apophyseal joints are not affected. Additionally, the erythrocyte sedimentation rate (ESR) is normal and there is no elevation in the HLA-B27 antigen.

A Guide To Key Signs And Symptoms Of Ankylosing Spondylitis

The symptoms of ankylosing spondylitis are generally insidious in nature and intermittent after the initial onset. Symptoms may often begin with low back pain that may radiate into the thighs. As the disease progresses, patients will have increasing pain with spinal stiffness and symptoms moving from the lumbar/sacral region up the spine. Associated symptoms that occur include fever, fatigue, loss of appetite, weight loss, acute uveitis or iritis, bowel inflammation, diminished chest expansion and anemia.

The symptoms of ankylosing spondylitis are generally insidious in nature and intermittent after the initial onset. As the disease progresses, patients will have increasing pain with spinal stiffness and symptoms moving from the lumbar/sacral region up the spine.

Although the symptoms of ankylosing spondylitis are usually restricted to the joints of the axial skeleton, 25 percent of all patients experience pain in the knee, hip or shoulder regions as well. Transient joint pain can occur in 50 percent of diagnosed cases of ankylosing spondylitis. Low back pain is the most common complaint on presentation. Patients state they are able to relieve their low back pain by leaning forward and this may account for kyphosis in untreated cases.

In addition to the low back pain in the lumbar/sacral region, patients may also experience radiating pain to the groin and buttocks area as well as the thighs. Since the onset of symptoms is intermittent and most commonly affects younger, otherwise healthy males, it is easy to confuse early symptoms of ankylosing spondylitis with mechanical low back pain. Indeed, clinicians should inquire about a family history of ankylosing spondylitis as well as other rheumatic conditions when patients present with back pain.

As the disease progresses, subsequent visits will reveal more persistent pain and stiffness, even at rest. The pain is now moving up the spine and affects the rib cage. In late stages of the condition, the spine becomes completely rigid and there is restricted movement of head and neck.

Again, it is important to remember that early in the disease, there may be no objective findings during the physical examination so clinicians will have to rely on subjective complaints. If you suspect ankylosing spondylitis based on the patient’s past medical and family history, conducting a thorough head to toe physical exam is important to document a baseline.

As the disease progresses and symptoms increase, more and more objective findings will become evident. One of the earliest objective items clinicians will see is the loss of lateral flexion of the lumbar/sacral spine. One may also detect sacroilitis by eliciting a pain response through percussion of the sacroiliac joints or applying pressure over the pelvis.

Clinicians can measure the patient’s range of motion with a goniometer, testing for forward flexion, backward extension, lateral flexion and spinal rotation. One should measure for these at follow-up visits so you can document the progression of the condition or treatment or both. As the condition develops, the normal lumbar curve is flattened while the thoracic curvature becomes more exaggerated. Chest expansion also becomes limited as a result of costovertebral involvement.

During follow-up visits, one may note other findings that can indicate comorbid conditions or complications associated with ankylosing spondylitis. Anterior uveitis is the most common of these conditions, affecting as many as 25 percent of patients. Cardiovascular disease chiefly manifesting itself as aortic insufficiency, EKG conduction defects, angina, cardiomyopathies and pericarditis occur in 3 to 5 percent of patients with longstanding ankylosing spondylitis. Clinicians may note the emergence of respiratory issues such as upper lobe fibrosis, cavitation and bronchiectasis and these can resemble tuberculosis. These symptoms usually occur after the onset of the skeletal symptoms has spread to the rib cage.

What The Diagnostic Testing May Reveal

Clinicians will note an elevated ESR in the vast majority of ankylosing spondylitis patients, approximately 85 percent. Unlike the majority of other rheumatologic diseases, serologic testing for rheumatoid factor is commonly negative. If you suspect ankylosing spondylitis, you should obtain a measurement of human leukocyte antigen B27 (HLA-B27). This antigen is present in 90 to 95 percent of patients with ankylosing spondylitis.

Here one can see moderate ankylosing spondylitis, a condition that is more frequent among men between the ages of 20 and 40.

While this finding is common, one cannot use this measurement as a specific diagnostic test since clinicians may find the antigen in 8 percent of healthy Caucasians and 4 percent of healthy African-Americans.
Regular X-ray imaging is the most effective method for detection, diagnosis and follow-up monitoring of ankylosing spondylitis. One usually sees the earliest changes in the sacroiliac joints. These abnormalities include initial widening, symmetric sclerosis and subsequent narrowing of the joint. Clinicians may also note subchondral erosions of the sacroiliac joints.

“Squaring” of the vertebral bodies along with demineralization and calcification will demonstrate the classic “bamboo spine.” One will usually see this presentation among patients who have had the condition for an average period of ten years.

Obtaining a CT scan is useful in evaluating sacroiliitis and clarifying otherwise subtle radiographic changes. Also be aware that the CT is not a primary study for imaging long segments of the spinal column due to high radiation exposure. Magnetic resonance imaging (MRI) is not an effective study due to poor detection of calcification, ossification along the spine and sacroiliac joints.

Pertinent Insights On Treatment

The primary treatment modalities of ankylosing spondylitis include the use of pharmacotherapy, physical therapy and exercise. The goal of pharmacotherapy is to reduce the inflammation in the spine and other joints. The goals of physical therapy and exercise are improving spinal movement, posture and lung capacity.
Nonsteroidal antiinflammatory drugs (NSAIDs) are the primary modality clinicians use in the treatment of ankylosing spondylitis. Since this class of medication is used to manage most inflammatory processes, clinicians will likely initiate NSAID medications prior to a definitive diagnosis of ankylosing spondylitis.

Physical therapy and exercise are important adjuncts in the treatment of ankylosing spondylitis as they are essential to maintaining spinal and joint mobility and proper posture.

In regard to the available NSAIDs, indomethacin seems to be the most effective. Keeping the potential toxicity in mind, clinicians should use the smallest dosage effective in controlling symptoms. A dosage of 25 to 50 mg three times daily is most common. Other commonly used NSAIDs include aspirin, naproxen, diclofenac and sulindac. These drugs commonly have side effects such as nausea, abdominal pain diarrhea and can exacerbate ulcer disease. Clinicians should instruct patients to take these medications with food in order to minimize these side effects.

While corticosteroids are good antiinflammatory agents, they have limited therapeutic value. These compounds are associated with multiple serious side effects when used as long-term treatment modalities. These side effects include osteoporosis, bruising, infections and destruction of the larger joints. When treating acute associated conditions such as iritis, topical corticosteroids and mydriatics are usually sufficient.

Researchers have found that slow acting drugs, such as gold injections, sulfasalazine and methotrexate, used to treat rheumatoid arthritis are ineffective for ankylosing spondylitis. While these drugs have demonstrated some relief for inflammation in the peripheral joints, they have not been successful in reducing inflammation in the spine.

Newer medications that are proving to be effective for ankylosing spondylitis are the tumor necrosis factor (TNF-a) inhibitors. Researchers have shown that medications such as etanercept (Enbrel), adalimumab (Humira) and infliximab (Remicade) are effective in stopping disease activity, decreasing inflammation and improving spinal mobility.

Charles A. Moxin, MPAS, PA-C is the President-Elect of the Association of Family Practice Physician Assistants and will assume the Presidency of the association in July. Mr. Moxin serves as a consultant and a member of the speaker’s bureau for a number of pharmaceutical companies. He is currently on staff at the Trevino Family Practice Clinics in San Antonio, Texas.

Physical therapy and exercise are important adjuncts to medicinal treatments. These exercises, treatments and instructions are essential to promote and maintain spinal and joint mobility, and proper posture. In cases in which the chest/rib cavity is affected, physical therapy and exercise allow for chest/lung expansion. Other modalities that can provide the patient with some relief include the use of heat and/or cold to help relax aching muscles, and reduce joint pain and stiffness. Relaxation techniques and coping skills can allow the patient to have a greater feeling of control and a more positive outlook.

Surgery may be indicated under several circumstances. In most cases, one may consider referring a patient for peripheral joint replacement (knee or hip) when the joint becomes badly eroded or the pain becomes too severe to tolerate. Spinal surgery is also a possibility when the downward curvature of the spine, particularly in the neck and upper thoracic area, becomes severe. However, there are considerable risks with this type of surgery.

Lori J. Markowitz, MS, PA-C, is the current Vice-President and the next President-Elect for the Association of Family Practice Physician Assistants. She also serves as the association’s Information Technology Manager. Ms. Markowitz is currently on staff at the Detroit Medical Center, St. John Detroit Riverview Hospital, and the Northway Medical Center. She works with Leonard E. Ellison, Jr., MD.

In regard to radiotherapy to the spine, clinicians should only consider this as a last resort referral option. Patients undergoing this treatment have 10 times the risk of developing myelogenous leukemia.
In regard to the conditions and complications of patients who have ankylosing spondylitis, clinicians should address these as soon as they occur and/or make appropriate referrals for treatment.

Closing Comments

Whenever clinicians diagnose or suspect that a patient has ankylosing spondylitis, they should ensure a subsequent evaluation by a rheumatologist. Primary care clinicians may conduct routine follow-up visits unless circumstances warrant otherwise. One should schedule follow-up visits for these patients every six to 12 months in order to monitor spinal mobility and posture. The presence of comorbid conditions may necessitate more frequent follow-up visits.


The course of ankylosing spondylitis varies and most will do well and live with a good quality of life with certain modifications as they get older. The vast majority of patients will have intermittent and subsequently persistent symptoms for decades after the diagnosis of ankylosing spondylitis. There are some patients who may experience a long-term remission but this is rare.

The prognosis is better in those patients who are able to maintain mobility and upright posture. The severity of the disease varies greatly from individual to individual. Approximately 10 percent of patients with ankylosing spondylitis will develop some degree of work disability in the first 10 years. Those who have developed disease in the hips within the first two years have a poorer prognosis. n