An inflammatory disease, ankylosing spondylitis (or AS) is characterized by pain and stiffness and can lead to loss of mobility. The disease process leads to both erosion of bone and increased bone formation in the spine, which can become fused; in advanced cases, this can lead to spinal deformity.
AS most commonly affects men in their teens and 20s, but it can affect anyone of any age. It is more common in men and tends to be milder when it does occur in women, making it more difficult to diagnose.
We will also explore how this form of arthritis is diagnosed, how symptoms can be relieved through drug treatments and physical therapy, plus information on how to reduce the risk of ankylosing spondylitis.
Fast facts on ankylosing spondylitis (AS):
- Ankylosing spondylitis is a type of arthritis.
- It mostly affects the lower part of the spine, and where it joins to the hips (sacroiliac joints).
- Ankylosing spondylitis can be difficult to diagnose but has a particular pattern of pain symptoms, and can be seen on X-ray and MRI.
- There is no cure for ankylosing spondylitis, but the pain and inflammation can be managed with drugs. Therapy can also relieve and prevent some of the effects of AS.
Pain and symptoms of ankylosing spondylitis
One of the common symptoms of ankylosing spondylitis is lower back pain.
Three main symptoms characterize ankylosing spondylitis:
- loss of mobility
Pain is the main symptom of ankylosing spondylitis, especially in the lower back and buttock areas in the early stages of the disease.
Although lower back pain is a key symptom of ankylosing spondylitis, the inflammation is not confined to the spine - it is systemic - meaning that inflammation and pain can also arise in other parts of the body, such as:
- in other joints (arthritis and synovitis symptoms)
- in the neck
- at the top of the shin bone in the lower leg
- behind the heel of the foot (inflammation - enthesitis - in the Achilles tendon)
- under the heel of the foot
AS can cause so-called bony fusion - an overgrowth of bones at the joints. This can make it difficult to carry out everyday tasks. In some cases, this can restrict movement of the chest and make it hard to breathe.
People with ankylosing spondylitis may also experience fatigue - a feeling of being tired and having low energy most of the time.
In about a quarter of cases, ankylosing spondylitis also affects the eyes, including the iris (the colored part of the eye) and other parts of the eye apparatus around it. This inflammation (known as iritis or uveitis, depending on the location) can cause redness and pain, and can impair vision impair vision if not treated.
Other systemic signs of the disease may include neurological and cardiovascular changes.
What are the treatments for ankylosing spondylitis?
Ankylosing spondylitis cannot be prevented or cured, and the damage caused by it cannot be reversed. However, there are some options available to help relieve symptoms and manage progression.
These options include:
- physical therapies and exercises
- surgery, only in rare cases
The most important step to take for people with ankylosing spondylitis is to seek help from doctors, including rheumatologists. This can require a number of clinic visits as the disease progresses slowly. However, proper medical care enables better monitoring and treatment programs.
The following two approaches are typically used in the management of ankylosing spondylitis:
- Drugs to reduce pain and inflammation.
- Physical therapy and exercises to maintain movement and posture.
Surgery is used only rarely, in severe cases, to correct great deformity - for example, when the spine is bent over too far - or to replace a joint, such as in hip replacement.
The main drugs used to ease the pain and inflammation of ankylosing spondylitis are nonsteroidal anti-inflammatory drugs (NSAIDs) - such as ibuprofen, naproxen, and diclofenac. Acetaminophen and codeine are also options if NSAIDs are unsuitable or insufficient.
Some NSAIDs compromise bone health by reducing the creation of new bone; this is why spinal fusion patients are usually told not to take NSAIDs after surgery. Other drug options are available, including:
- Locally injected corticosteroids.
- Disease-modifying anti-rheumatic drugs (DMARDs) - such as sulfasalazine (brand names: Azulfidine or Sulfazine) and methotrexate (Otrexup, Rheumatrex, or Trexall).
- Tumor necrosis factor (TNF) antagonists - adalimumab (Humira), certolizumab (Cimzia), etanercept (Enbrel), golimumab (Simponi), or infliximab (Remicade).
- Other biologic treatments - secukinumab (Cosentyx).
Physical therapy and exercise
Physical therapy can help relieve the symptoms of ankylosing spondylitis.
Physical therapy and exercises for ankylosing spondylitis can help prevent symptoms. A physical therapist will design a program that can help patients maintain good posture and motion in the joints. This might include:
- daily exercises
- special training
- therapeutic exercises
Physical therapy exercises are referred to as strengthening exercises and range-of-motion exercises. There are many ways to do them, including while in water.
Because of the systemic nature of ankylosing spondylitis, patients may meet with doctors from a wide range of disciplines, including:
- Ophthalmologist (for eye disease).
- Gastroenterologist (for bowel disease).
- Physiatrist (a medical doctor specializing in physical medicine and rehabilitation - not to be confused with psychiatrist).
What causes ankylosing spondylitis?
Doctors know a lot about how ankylosing spondylitis develops and leads to symptoms, but are still trying to understand what causes the disease.
The symptoms of ankylosing spondylitis are caused by inflammation of parts of the lower spine. This inflammation can lead to damage and fusion - through the growth of new bone.
The fusion can develop as a result of the inflammation of the tissues that connect to bones, but it is not yet known why this chronic inflammatory process occurs in people with ankylosing spondylitis.
The condition often runs in families and is known to have a genetic component.
Diagnosing ankylosing spondylitis
The first step towards a diagnosis of ankylosing spondylitis is a consultation with a doctor who will also carry out a physical examination, and arrange tests where necessary.
There are, however, telltale features that may help to make the diagnosis. If the doctor sees the following features of inflammatory back pain, ankylosing spondylitis may be the culprit:
- It does not improve with rest.
- It causes sleep disturbance.
- Gradual onset of back pain before the age of 40, and not caused by injury.
- The complaint has persisted for longer than 3 months.
- There is spinal stiffness in the mornings, and symptoms improve with exercise and motion.
Imaging tests may confirm the diagnosis, but changes may not be immediately visible on such tests, which can delay diagnosis.
Before referring a patient to a rheumatologist and radiologist for further investigation and imaging, the doctor may order blood tests. While no blood tests can confirm ankylosing spondylitis, they can add weight to a likely diagnosis and rule out other causes of symptoms.
The tests for inflammation include erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complete blood count (CBC). A genetic test (HLA B27) may be ordered. If other causes such as rheumatoid arthritis are suspected, testing for rheumatoid factor (RF), cyclic citrullinated peptide (CCP), and antinuclear antibodies (ANA) can help to rule out these conditions.
The following imaging tests assist in diagnosis:
- X-rays - can reveal changes to the spine and pelvis, showing both early and more advanced signs of ankylosing spondylitis.
- MRI and ultrasound - these scans may also be used to investigate ankylosing spondylitis, and MRI of sacroiliac joints (SI joints) can reveal earlier signs of the condition. Ultrasound is not yet a routine part of testing.
The diagnosis of AS is helped with these imaging tests, but requires additional information such as a physical examination to confirm.