What is Spondyloarthritis?
Spondyloarthritis (SpA) describes a group of chronic inflammatory diseases with common clinical, genetic, and pathogenic features that cause pain and stiffness in your back. It can also affect the knees, hips, eyes, skin, and gastrointestinal tract.
Although SpA causes primarily inflammation of the spine, the inflammation and pain are often systemic, which means you experience symptoms all over your body. You may experience symptoms in your other joints, including your neck, shoulders, hips, or ankles.
Spondyloarthritis is an immune-mediated disease, meaning your own immune system is attacking the body. The immune system is supposed to recognize and attack bacteria and viruses, but in an autoimmune response, it sees its own cells as invaders and releases antibodies that damage healthy cells and tissues.
Classifications of Spondyloarthritis
Traditionally, the medical community used distinct names for each disease in the Spondyloarthritis group. Today we use only two classifications, Axial Spondyloarthritis (axSpA) and Peripheral Spondyloarthritis (pSpA).
Axial spondyloarthritis (AxSpA): causes inflammation in the spine and sacroiliac joints. AxSpA has two classifications; non-radiographic and radiographic. Radiographic axSpA is the same as Ankylosing Spondylitis.
Peripheral spondyloarthritis (pSpA): causes inflammation in areas away from the spine and sacroiliac joints. Common sites can include joints such as fingers, arm, foot, leg joints, the skin, and the insertion points where ligaments connect muscles to bones.
The new classifications reflect a better understanding of SpA diseases. The result has been a better chance of early diagnosis and treatment for patients, and better life outcomes.
In the case of Ankylosing Spondylitis (AS), the prototypical SpA disease, one feature required for diagnosis is for damage to the sacroiliac joint to be visible on an x-ray. Because X-rays cannot detect damage until about 7 or 8 years after disease onset, many patients had to wait until their disease caused painful and permanent damage to their bodies in order to get a diagnosis.
We know that the pain and inflammation that causes sacroiliac damage started many years earlier and that early treatment can lessen the impact of AS. That early damage gave rise to a new name, non-radiographic axial spondyloarthritis:
Non-radiographic, meaning not visible on x-rays
Axial, meaning the skull, the vertebral column, the sternum, and the ribs constituting the axial skeleton.
Spondyloarthritis meaning inflammatory back pain
The new classifications reflect a better understanding of the early stages of SpA including signs and symptoms as well as how the disease changes over time.
Not all patients with non-radiographic axSpA will progress to the radiographic stage or AS. In fact, while the male-to-female ratio for axSpA is 1:1, it is known that more men than women progress to the radiographic stage. Regardless of the stage, the disease burden is the same.
For reference, here are the traditional names of the Spondyloarthritis group of diseases that you may still see used.
- Ankylosing spondylitis (AS) – inflammation in the spine and sacroiliac joints.
- Psoriatic arthritis (PsA) – causes inflammation of the skin and nails, and may include the spine
- Enteropathic arthritis (EnA) – Arthritis that is associated with Inflammatory Bowel Disease (Crohn’s Disease and Ulcerative Colitis)
- Reactive arthritis (ReA) – arthritis pain that develops in a reaction to an infection
- Juvenile idiopathic arthritis (JIA) that is Enthesitis related arthritis (JIA-ERA) – also called juvenile spondyloarthritis (jSpA) – arthritis pain starting before a patient’s 16th birthday
- Undifferentiated spondyloarthritis (uSpA) – causes spondyloarthritis pain with symptoms that didn’t fit the traditional classification
You can view the below Venn diagram to see how the various spondyloarthritic diseases intersect
What are the signs and symptoms of Spondyloarthritis?
Inflammatory Back Pain
Inflammation with pain and stiffness in your back is the core feature of all spondyloarthritis. Your pain may be centered in the lower back and hips, but you may also feel pain and stiffness in your upper back and neck.
Often, a SpA patient has had chronic back pain for many years before seeking a diagnosis.
Early symptoms of inflammatory back pain can be mistaken for an injury. One major difference is SpA pain is usually worse in the morning and eases somewhat with some movement or light exercise. Also, mechanical back pain usually heals within a few weeks. Inflammatory Back Pain lasts more than three months.
Inflammation and pain in joints outside of the spine and hips is another common sign of SpA. The skin, shoulders, wrists, hands, knees, ankles, and feet are common sites for peripheral arthritis to present.
Although peripheral arthritis symptoms are similar to rheumatoid arthritis (RA), we know they are different because people with RA have rheumatoid factor antibodies in their blood that can be seen on a blood test (seropositive), while people with SpA do not (seronegative).
It takes a lot of energy for the body’s immune system to mount a response. That’s why we need to rest when we’re fighting off a cold or the flu.
An immune response doesn’t end after a couple of days in bed. When the immune system is constantly attacking healthy cells, it can make a patient feel tired and lacking in energy. In order to maximize your rest, be sure to practice good sleep hygiene and put your electronic devices down at least an hour before you go to bed.
People suffering from Spondyloarthritis can experience other conditions known as Extra Musculoskeletal Manifestations (which used to be called Extra Articular Manifestations) and comorbidities.
The most common Extra Musculoskeletal Manifestations are Acute Anterior Uveitis (inflammation of the uvea in the eye); Inflammatory Bowel Disease and Psoriasis.
People with SpA are at greater risk of comorbidities because of the inflammation and skeletal damage that can be caused by the disease. Comorbidities include cardiovascular diseases, pulmonary diseases such as restrictive lung disease, renal diseases, and osteoporosis, with the risk of fractures.
It is nearly impossible to diagnose axial spondyloarthritis without imaging. The preferred imaging is MRI (Magnetic Resonance Imaging) because it can detect inflammation and erosions in the sacroiliac joints (SIJ), key features of axSpA, many years before they can be detected radiographically (x-ray). When your doctor orders imaging of your pelvis and spine, they are looking for sacroiliitis, inflammation of the SIJ, bone damage in the SIJ, or bony growth (syndesmophytes) in the vertebrae.
New bone growth in the spine is a feature of more severe axSpA. The bone grows as a bridge between vertebrae causing a rigid or ‘bamboo’ spine, leading to a loss of flexibility and possible disability.
In Peripheral SpA, enthesitis can be detected by MRI. Enthesitis is inflammation of the entheses, the points where tendons and ligaments attach to bone. You may feel pain and tenderness in your back, hips, and back of your heel and experience some swelling.
Imaging can reveal damage to the hip joint. Long-term cycles of inflammation can cause damage to the bones in the pelvis and hip. Hip replacements may be required in relatively young patients.
At the CSA, our goal is to help SpA patients receive a diagnosis as early as possible. Early treatment can delay or prevent damage to the SI joint and bones. If your MRI does not show progressive signs of SpA, ensure your doctor acknowledges your other symptoms and medical history.
Main Causes and Treatments
What causes Spondyloarthritis?
We do not know the cause of spondyloarthritis. However, genetics play an important role in the disease. For those people who have a genetic predisposition to SpA, there has to be a trigger for the disease.
In the diagnosis process, your doctor will order imaging of the pelvic area looking for sacroiliitis and bone erosions. They may also order blood tests to look for the HLA-B27 gene, associated with spondyloarthritis since the 1970s, and inflammatory markers. HLA-B27 has a strong correlation with SpA, which means testing for it helps with diagnosis, although the presence of the gene is insufficient information on its own to make a diagnosis.
Depending on ethnicity, up to 90% of people with Spondyloarthritis have the HLA-B27 gene, while as many as 50% of patients do not. This discrepancy leads researchers to believe that there are additional genetic factors that contribute to SpA.
At least 110 different genes have been discovered that have a link to spondyloarthritis. After HLA-B27, the genes with the largest contributions are ERAP1 and IL-23R. Research is continuing worldwide to identify additional genes associated with SpA. There could be hundreds more, although their contribution to the disease mechanism will be minute. This research is important to understanding how genes may affect a patient’s likelihood of developing disease and in developing new therapies.
Who Gets Spondyloarthritis?
A family history of SpA increases the likelihood of developing the disease, due to the genetic influence. Knowing if family members also suffer from SpA when seeking a diagnosis is always helpful. However, not every family member will develop the disease. While the cause of SpA is not yet known, it is thought that mechanical stress or bugs, particularly in the microbiome, can trigger it in some people with a genetic predisposition to the disease.
Spondyloarthritis often starts in the teen years and early twenties. Onset after age 45 is unusual.
The HLA-B27 gene plays an important role in the disease’s pathogenesis (origin and development). Current theories are that the gene ‘misbehaves’ in some way, causing the body’s immune system to attack itself.
The HLA-B27 gene varies by ethnic group and geography plays an important role in the pathogenesis (origin and development) of the disease.
The prevalence of HLA-B27 varies in different populations It is non-existent in Australian Aboriginal populations and is well below 1% among Black Africans. In some communities like the Inuit and Haida in North America, the prevalence can be as high as 40%-50% respectively.
The first recommended treatment is to exercise. That is, to be active, stretch, and keep moving. There are many resources for exercises for Spondyloarthritis that maintain the patient’s flexibility and range of motion. The importance of exercise cannot be overstated. Any activity is better than no activity. Activity should encompass exercises for stretching, strength, and stamina. Walking is a good form of exercise, as is swimming. Many patients do yoga, tai chi, and Pilates, which together with some form of cardio training, are excellent forms of exercise for SpA.
NSAIDs, non-steroid anti-inflammatory drugs, are the primary drugs for treating SpA. Patients with SpA usually respond very well to NSAIDs. There is a risk to taking NSAIDs for a long time, but often patients do well taking NSAIDs on demand once their inflammation has been controlled by a continuous course of NSAIDs.
Local glucocorticoid (a class of steroids) injections may be prescribed for persistent joint inflammation, but long-term treatment by glucocorticoids is not recommended.
Analgesics (general pain relievers) may be prescribed in combination with other treatments that have failed to control pain.
Disease-Modifying Anti-Rheumatic Drugs (DMARDs) include methotrexate and sulfasalazine. DMARDs are more effective for peripheral disease.
bDMARDS or Biologic Disease Modifying Drugs are very effective in SpA and are known to stop disease progression. The current biologics approved for SpA include TNF Inhibitors and IL-17a Inhibitors, given by infusion or injection. A problem with biologics is that until precision or personalized medication is better perfected, it is not known which biologic is best suited to which patient. This means that patients may have to try two or more biologics before finding the one that works for them. Other concerns with biologics are that any one biologic works only in roughly 70% of the patients to whom it is given, and the tendency for the efficacy of the drug to wear off over time for even those biologics that work well for a patient to begin with.
A special type of DMARD is JAK Inhibitors, which are taken in pill form and are new in the treatment of SpA.
Other recommendations for the management of SpA include membership in a patient organization, education about the disease, belonging to a support group, and physical therapy, all of which have been shown to improve patient outcomes.
Types of Spondyloarthritis
Spondyloarthritis (SpA) presents in various ways, with different symptoms, diagnosis and treatment options.
They are classified as:
Axial Spondyloarthritis (AxSpA)
Axial spondyloarthritis, with Ankylosing Spondylitis (AS) as its prototype, is a chronic, progressive, painful form of inflammatory arthritis, the hallmark of which is sacroiliitis.
The symptoms of axSpA include:
- A slow or gradual onset of back or buttock pain over weeks or months.
- Early morning stiffness or pain that wears off during the day as you move
- Chronic back pain (lasting for more than 3 months)
- Feeling better after exercise and worse after rest, particularly at night
- Interrupted sleep, tiredness and Fatigue
- Loss of appetite, weight loss
- In the early stages – mild fever
- Pain that is dull and persistent on one or both sides of the body
- Pain that starts in or spreads to the joints on the hands or feet
- Iritis or Uveitis, inflammation of the eyes
Onset of axSA
The onset of axSpA is usually before age 45, and typically people start experiencing symptoms in their late teens or twenties. Women can experience more pain in the neck, hips, and knees than men, making their diagnosis more difficult. There is also outdated and inaccurate information that women do not get r-axSpA/AS; for many years Ankylosing Spondylitis (AS) was referred to as a “man’s disease”.
Other effects of axSpA
There are additional effects, or extra musculoskeletal manifestations, of axSpA for many patients. These include acute anterior uveitis (inflammation of the uvea of the eye). As many as 50% of patients with axSpA have experienced uveitis, usually in one eye only, over their lifetime. About 10% of patients will experience Inflammatory Bowel Disease (IBD – ulcerative colitis or Crohn’s Disease) while 5%-10% will have psoriasis.
Diagnosis of Axial Spondyloarthritis
One of the biggest challenges facing patients with axSpA is the length of time it takes for most patients between when they began experiencing symptoms to being properly diagnosed with the disease. There are many factors that contribute to this delay to diagnosis. These include a lack of awareness amongst the general public and in some cases the medical community of axSpA and the difference between mechanical back pain and inflammatory back pain. Another is that the disease can be difficult to diagnose even when a form of SpA is suspected.
Back pain is one of the most common complaints that people take to their family physicians and other healthcare practitioners. Most people will experience some form of back pain in their lives. For some, it is relatively minor inconvenience, whereas others are unable to work and function as they want to because of severe back issues.
The vast majority of back pain is mechanical in nature. In the early stages, inflammatory and mechanical back pain can be difficult to tell apart, but if you are younger than 45 years old with back pain persisting for longer than 3 months, and experience morning back stiffness that eases with activity, you should ask your physician about axSpA.
Mechanical or acute back pain comes from some dysfunction in the structures that connect to your back, including the spine, muscles, and discs. Mechanical back pain can happen at any time in your life and generally comes on quickly and lasts for a short period, up to a few months. It can also often be eased with rest and care from your doctor or other healthcare practitioner, like a physiotherapist or chiropractor. If you’ve ever thrown your back out, or had a bout of sciatica, you’ve experienced mechanical pain.
Inflammatory back pain is caused by an autoimmune response, when your body attacks healthy tissues, causing inflammation and pain. The pain comes on slowly and persists for many months or years. The pain and stiffness are usually worse in the morning but improve with some movement and light exercise.
Inflammation can be localized to your back and hips, but usually the inflammation causing pain is systemic, which means you may also experience pain or swelling in other parts of your body. Common areas include the eyes, ankles, and neck.
Inflammatory back pain often interrupts sleep or can make sleep difficulties worse. Your immune system working so hard against your body is also exhausting. It’s normal for someone experiencing inflammatory back pain to feel exhausted much of the time.
A rheumatologist is a specialist to whom you should be referred by your family physician.
The rheumatologist will conduct a thorough physical exam, take a medical history including any family history of Spondyloarthritis diseases, look for the presence of any spondyloarthritis features, and finally order MRIs. They may also order blood tests for inflammatory markers and a test for the gene HLA-B27.
It is important to know that there is no single definitive test for axSpA or any of the spondyloarthritis diseases. There are also no commonly accepted diagnostic criteria for axSpA. Although classification criteria exist, such as the ASAS and Modified New York Criteria, diagnostic and classification criteria are not interchangeable and care should be taken to not use classification criteria for diagnosis.
A diagnosis of axSpA is confirmed by the presence of sacroiliitis in MRIs or X-rays. One of the difficulties of diagnosis is in using X-rays since damage to the sacroiliac joints typically does not show up on X-ray until many years after disease onset. It is a contributing reason why there is such a long delay in diagnosis for many. The average delay to diagnosis is 7-9 years in Canada. For this reason, Magnetic Resonance Imaging (MRI) is the standard for diagnostic imaging because it can detect sacroiliitis much sooner after disease onset. It has been shown that Bone Marrow Edema (BME) in the SIJ, can appear in healthy young athletes and in postpartum women. This means that reading an MRI of the SIJ has to be done very carefully to ensure that the evidence of BME shows sacroiliitis and not something else.
Your rheumatologist may ask you to complete some questionnaires, such as the Bath Ankylosing Spondylitis Disease Activity Index, known as BASDAI, in order to help with the diagnosis and more importantly, to establish a baseline for disease progression. There are several Bath Indices, including the Bath AS Functional Index (BASFI), the Bath AS Radiology Index (BASRI), and the Bath AS Metrology Index (BASMI), which measures changes in spinal mobility. These indices are also applicable to people with nr-axSpA.
Psoriatic Arthritis is defined as inflammatory arthritis associated with psoriasis, a chronic inflammatory skin condition that presents most commonly with itchy and painful red scaly patches on the skin of the elbows, knees, and scalp. Psoriasis can also affect the nails, which can be pitted, split, discoloured, and loose because of the condition.
About 20%-30% of patients with psoriasis will develop Psoriatic Arthritis. PsA begins gradually and involves one or more peripheral joints to begin with, quickly spreading to other joints. Any and all joints can be involved, including the spine. The common features of PsA are enthesitis, inflammation of the site where tendons and ligaments attach to the bone; dactylitis, inflammation of the fingers or toes resulting in ‘sausage digits’, and spondylitis, inflammation of the spine including the sacroiliac joints and vertebrae.
About 15% of people suffering from PsA develop arthritis before they have signs of psoriasis of the skin.
Symptoms of psoriatic arthritis:
- Scaly skin patches
- Dactylitis – ‘Sausage’ fingers and toes caused by swelling of the joints
- Pain and swelling from enthesitis, particularly in the plantar fascia (soles of feet) and the Achilles tendon (back of the heel) but also in any joints.
- Pain and stiffness in the spine, especially at rest
- Discolouration of fingernails and toenails, together with pits, indentations, and crumbling
- Iritis or red, painful eyes
The second subclassification of Spondyloarthritis is Peripheral SpA, which causes inflammation in joints and/or tendons outside the spine or sacroiliac joints. These can include the hands, wrists, elbows, shoulders, knees, ankles, and feet. Inflammation of the tendons can occur in the fingers or toes (dactylitis, colloquially known as sausage fingers) or where tendons and ligaments meet with bone (enthesitis).
Peripheral SpA includes what have traditionally been, and are still referred to as, Psoriatic Arthritis (PsA), Enteropathic Arthritis (EnA), Reactive Arthritis (ReA), and Undifferentiated Spondyloarthritis (USpA). They are now grouped together as Peripheral Spondyloarthritis because they all share features of peripheral arthritis, enthesitis and/or dactylitis.
Diagnosis of Peripheral SpondyloarthritisDiagnosis can be challenging, particularly in the absence of SpA extra-musculoskeletal manifestations such as uveitis, psoriasis, or inflammatory bowel disease.
Evaluation of disease activity by a rheumatologist should always include an assessment of objective signs of inflammation, particularly when enthesitis is the only peripheral manifestation. The rheumatologist will conduct a thorough physical exam, take a medical history including any family history of Spondyloarthritis diseases, look for the presence of any spondyloarthritis features, and finally order MRIs. They may also order blood tests for inflammatory markers and a test for the gene HLA-B27.
The key features of peripheral Spondyloarthritis that will assist in the diagnosis of the patient are arthritis, enthesitis, or dactylitis.
Enteropathic arthritis (EnA) is also called Inflammatory Bowel Disease (IBD) related arthritis. Patients with EnA have both chronic swelling in their joints and inflammation in part of their digestive tract. Up to 10% of patients with spondyloarthritis will develop IBD, particularly Crohn’s Disease but also ulcerative colitis.
Symptoms of Enteropathic arthritis:
- Abdominal pain
- Bloody diarrhea
- Weight loss
- Pain and swelling in joints, particularly in the lower limbs
- Stiffness and pain in the spine
For more information on Enteropathic arthritis, we recommend these resources here
Juvenile Onset Spondyloarthritis
Children with onset of arthritis before the age of 16 years are classified as having juvenile idiopathic arthritis (JIA). Children with enthesitis and/or sacroiliitis are further classified as having JIA that is enthesitis-related, which is commonly called Juvenile Spondyloarthritis.
Unlike adults with SpA, jSPA or JIA-ERA often starts as peripheral arthritis or enthesitis, with axial (back related) manifestations appearing much later.
Symptoms of juvenile spondyloarthritis
- Enthesitis, especially in the lower body
- Pain in the pelvis, hips, knees, and ankles
- Swollen knees and ankles
- Pain and inflammation in the spine
- Psoriasis and other skin rashes
- Uveitis or iritis
- Crohn’s disease or colitis (inflammation of the intestines)
- Tiredness and fatigue
Diagnosis of juvenile onset spondyloarthritis
A pediatric rheumatologist is best placed to provide a diagnosis because JSpA symptoms can come and go. A thorough physical exam looking for enthesitis and a complete health history recording symptoms and a family history will help with the diagnosis. Although the presence of HLA-B27 may be useful in helping with the diagnosis, it does not provide a definitive diagnosis.
Reactive Arthritis (formerly known as Reiter’s Syndrome)
Reactive arthritis is a painful form of inflammatory arthritis that develops in reaction to infection elsewhere in the body, usually in the gastrointestinal or genitourinary (urinary and genital) systems. Reactive arthritis can cause inflammation and pain in joints, the skin, eyes, genitals, and bladder. It can cause persistent lower back pain. As usual, some, but not all, people who are diagnosed with reactive arthritis carry the HLA-B27 gene.
Reactive arthritis is uncommon. For most people, symptoms eventually disappear within 12 months. Flares may be experienced afterwards from time to time and some people may go on to develop arthritis that may be either mild or severe.
Symptoms of reactive arthritis
- Dactylitis – ‘Sausage’ fingers or toes
- Pain, swelling and stiffness in joints
- Skin rashes
- Fingernails and toenails that are thickened and abnormal looking
- Iritis, uveitis, conjunctivitis
- Enthesitis (inflammation where tendons attach to the bone)
- Cystitis (inflammation of the bladder or urinary tract)
- Genital blisters and sores
- Lower back or pelvic inflammation and pain
The term USpA was introduced to classify patients who have the signs and symptoms of SpA but who could not be definitively diagnosed with AS, psoriatic arthritis, or the other SpA conditions.
These patients, over time, may progress to axSpA or develop psoriatic arthritis allowing them to be re-categorized into those entities. However, as the new classification system of axial and peripheral SpA encompasses most patients with SpA, there are very few patients who are classified as USpA now.
Symptoms of undifferentiated spondyloarthritis (USpA)
- Back pain
- Pain and swelling in the fingers or toes
- Buttock pain on one or both sides
- Heel pain
- Tiredness and fatigue
Could I have Ankylosing Spondylitis/axial Spondyloarthritis?
Mechanical vs Inflammatory Back Pain
Everyone experiences back pain. For some, it’s a minor annoyance. For others the pain becomes a barrier to their daily activities and work and treatment is sought. For others, the pain can be completely debilitating.
The vast majority of back pain comes from some dysfunction in the structures that connect to your back, including the spine, muscles, and discs. This is called “Mechanical” or “Acute” back pain.
Mechanical back pain can happen at any time in your life and generally comes on quickly and lasts for a short period, up to a few months. It can also often be eased with rest and care from your doctor or other healthcare practitioner, like a physiotherapist or chiropractor.
If you’ve ever thrown your back out, or had a bout of sciatica, you’ve experienced mechanical pain.
However, there is another cause for back pain that can’t be traced back to a mechanical source.
Inflammatory back pain is caused by an autoimmune response, when your body attacks healthy tissues, causing inflammation and pain.
The pain comes on slowly and persists for many months or years. The pain and stiffness are usually worse in the morning but improve with some movement and light exercise.
Inflammation can be localized to your back and hips, but usually the inflammation causing pain is systemic, which means you may also experience pain or swelling in other parts of your body. Common areas include the eyes, ankles, and neck.
Inflammatory back pain often interrupts sleep or can make sleep difficulties worse. Your immune system working so hard against your body is also exhausting. It’s normal for someone experiencing inflammatory back pain to feel exhausted much of the time
Could I have Spondyloarthritis?
The pain you are experiencing may be inflammatory, a condition broadly known as spondylitis (a term meaning inflammation of the spine). There are many things that cause spondylitis, including a condition called Axial Spondyloarthritis.
(You may also hear Axial Spondylarthritis (AxSpA) called Ankylosing Spondylitis (AS) or Non-radiographic axSpA (nr-AxSpA)).
Early Diagnosis is Important
The earliest possible diagnosis and treatment are vital to managing your condition and improving long term outcomes, including prevention of irreversible damage caused by inflammation. If you think you have inflammatory back pain, take the quiz and discuss your concerns with your doctor.
Unfortunately, in Canada, it takes an average of 7-9 years for people with AxSpA to receive a diagnosis. Women often take longer than men to be diagnosed, partially due to the fact that ankylosing spondylitis was often seen as a “man’s disease”.
When you complete the quiz, we will send your responses and tools you can use to track your symptoms and communicate your concerns.
This tool is designed to help people understand if they may have axial Spondyloarthritis or Ankylosing Spondylitis. If you suspect that you may have another form of Spondyloarthritis, please review the information we have on other Spondyloarthritic conditions here
This quiz has been adapted from the NASS Symptom checker, found here.