Ankylosing Spondylitis

What is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a chronic inflammatory disease that cause pain and stiffness in the back, neck and sometimes in other joints such as the hip and heels¹.

AS begins with inflammation around the bones in the spine or some joints, and later, it can sometimes cause the bones in the spine to fuse together, resulting in the loss of flexibility and the fusion of the spine, resembling “bamboo” with an immobile position^1,2.

WHICH JOINTS ARE AFFECTED BY ANKYLOSING SPONDYLITIS?

Frequency of inflammation per region⁶

WHAT CAUSES ANKYLOSING SPONDYLITIS?

AS is an inflammatory disease of unknown aetiology, with a higher incidence in young males^2,3. As an autoimmune disease, AS develops through complex interactions between genetic background and environmental factors².

Genetic background
AS is associated with the presence of the allele HLA-B27.
In fact, 90-95% of AS patients are HLA-B27 positive².

Environmental risk factors
But AS does not develop in every person who is HLA-B27 positive; thus, it is clear that environmental factors are important. Even first-degree relatives who
are HLA-B27 positive do not uniformly develop the disease².

ASIDE FROM GENETICS, OTHER FACTORS ARE THOUGHT TO BE INVOLVED:

Intestinal microbiome: up to 70% of patients with AS have subclinical intestinal inflammation, suggesting that the origin of the disease may be in the gut
Infections
Mechanical stress
Changes in the immune system
Gender

WHAT ARE THE SYMPTOMS OF ANKYLOSING SPONDYLITIS?

The course of AS and its onset varies greatly from person to person, but symptoms generally start to appear in late adolescence or early adulthood (between 17 and 45 years old)⁵.

The most common symptom is pain in the lower back and buttocks. This pain usually⁵:

OTHER MANIFESTATIONS OF ANKYLOSING SPONDYLITIS

Extra-articular involvement

Extraskeletal organs may also be affected by this disease. The most common extraarticular manifestations of AS include⁷:

>50% Inflammatory bowel disease

25% to 35% Acute anterior uveitis

-10% Psoriasis

AS is also associated with⁷:

An increased risk of cardiovascular disease.
Pulmonary complications as diminished chest wall expansion and decreased spinal mobility predispose patients to a restrictive pulmonary pattern.

HOW WILL MY DOCTOR DIAGNOSE MY DISEASE?

AS is diagnosed based upon the recognition of a pattern of clinical, laboratory, and imaging finding characteristic of the disease^8,9.

Physical examination⁹
Assessment of your flexibility and joint tenderness.
Blood test to look at inflammatory markers^8,9
C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) can be assessed in patients suspected of AS.
Blood test which can identify if you carry the HL-B27 gene⁹
X-rays⁹
X-rays will show if there have been any changes to your bones and joints such
as extra bone growth or fusion.
Magnetic resonance imaging (MRI) fusion⁹
MRI will show if there is any inflammation around your joints.

WHAT ARE THE TREATMENT OPTIONS?

Treatment depends on your symptoms and how severe your condition is¹.

The goal of treatment is¹:

To relieve your symptoms
To help you do your normal activities
To keep your condition from causing other problems

Non-pharmacological interventions^2,10

Patient education
Exercises and physical therapy
Smoking cessation

The use of a biologic agent for AS is particularly appropriate for those with high or very high disease activity, although they are effective in patients with mild to moderate symptoms as well¹⁰.

PHARMACOLOGICAL TREATMENT

Nonsteroidal anti-inflammatory medications (NSAIDs)
In many patients, NSAIDs are the only medications required as they are efficient in alleviating AS symptoms in 70-80% of patients.

Biologic therapy
Tumour necrosis factor (TNF)-α inhibitors. TNF inhibitors are recommended for patients with an inadequate response to initial therapy with NSAIDs.
Interleukin (IL)-17 inhibitors. In patients who have contraindications to the use of TNF inhibitors, treatment with IL-17 inhibitors is recommended.

Glucocorticoids
Local injections of glucocorticoids into the involved joint are an option for treating arthritis as they could provide immediate symptom relief.

WHAT CAN I DO TO MANAGE MY DISEASE?

You can reduce the chance that your conditions will cause problems if you¹:

Stop smoking (you will be less likely to have breathing problems)
Get plenty of calcium and vitamin D (you will keep your bones from getting weak)
Do exercise (you will prevent some of the stiffnes caused by AS)
Use a thin pillow (sleeping on a thick pillow can cause neck problems in people with AS)