Ankylosing Spondylitis - Symptoms, Causes, Complications, Diagnosis & Treatment

Ankylosing spondylitis definition

It is a type of arthritis which causes inflammation or swelling in the joints and ligaments of the spine. It can also affect peripheral joints such as knees, ankles, and hips. There is no known cause of ankylosing spondylitis (AS), but it is thought to be linked to a particular gene variant known as HLA-B27. Symptoms include back pain, a straight and stiff spine, extreme tiredness, loss of appetite, and weight loss. A rheumatologist can treat ankylosing spondylitis.

Ankylosing spondylitis meaning

The term ankylosing spondylitis is a combination of two words: "ankylosis" and "spondylitis"

The term “ankylosis” means stiffening of joints, which is caused by the fusion of two or more bones into one. 

The term “spondylitis” is derived from the Latin language “spondylo” which means “of the vertebrae”, and “itis” meaning "inflammation". Together, it means inflammation of the vertebrae.

Ankylosing Spondylitis Prevalence

Prevalence of ankylosing spondylitis worldwide 

The prevalence of ankylosing spondylitis is thought to vary across different regions. The mean prevalence of ankylosing spondylitis per 10,000 (from 36 eligible studies) was 23.8 in Europe, 16.7 in Asia, 31.9 in North America, 10.2 in Latin America, and 7.4 in Africa. 

Prevalence of ankylosing spondylitis in India

According to epidemiological studies, the prevalence of ankylosing spondylitis (AS) in India is estimated to be between 7 to 9 cases per 10,000 people. Males are more likely to have AS than females (male-to-female ratios can reach 16:1), and the condition usually manifests in the early 20s and 30s. Although this prevalence may differ by region due to genetic and environmental factors, it is consistent with global estimates that range from 0.1% to 1.4%.

Ankylosing Spondylitis Causes

There is no known cause of ankylosing spondylitis, but a few studies show that both genes and the environment may lead to the development of the disease. The HLA-B27 gene can increase the risk of developing ankylosing spondylitis, but that does not mean that everyone with this gene will develop the disease.

Ankylosing Spondylitis Symptoms

The symptoms of ankylosing spondylitis may come and go over time. These symptoms may be different in different among individuals. The following are some of the ankylosing spondylitis signs and symptoms: 



• Back pain, which is usually severe at night, especially during rest
• Early morning stiffness
• Straight and stiff spine
• Inability to take a deep breath, if the joints between the ribs and spine are affected
• Loss of appetite 
• Weight loss
• Tiredness or fatigue 
• Fever
• Anemia
• Joint pain
• Inflammation of the eye
• Organ damage, such as to the heart, lungs, and eyes
• Rashes on the skin
• Digestive illness

Ankylosing Spondylitis Risk Factors

Ankylosing spondylitis is chronic arthritis which causes inflammation, pain, and stiffness mostly in the spine and the sacroiliac joints, which are located just above the tailbone. There are several factors which can increase the risk of developing ankylosing spondylitis. The following are some of the risk factors of ankylosing spondylitis:

• Age: Ankylosing spondylitis occurs more commonly in young adults. Though degenerative arthritis is associated with aging, inflammatory back pain usually occurs at a younger age. Almost 80 percent of patients will experience early symptoms before the age of 30, and merely about 5 percent of ankylosing spondylitis patients will experience the symptoms at the age of 45 or older. 

• Gender: Because of the overwhelming diagnosis of ankylosing spondylitis in men compared to women, it used to be considered a man’s disease. Men are more likely to get radiographic damage (damage to the spinal joints, which is visible on X-rays). Non-radiographic axial spondylarthritis, having the same symptoms as ankylosing spondylitis but without causing radiographic damage, is more commonly seen in women. Ankylosing spondylitis may be misdiagnosed in women, and women tend to be diagnosed later compared to men, and they experience more misdiagnoses. 

• Genes: Certain types of genes play a key role in the developing ankylosing spondylitis; one of the genes is the HLA-B gene, which is part of a gene family called the human leukocyte (HLA) complex. This gene has hundreds of variations, each one of them differentiated by a number. One of these gene variations, HLA-B27, has a strong connection to the development of ankylosing spondylitis. But it is important to note that ankylosing spondylitis can develop without being positive for HLA-B27 and also being positive for HLA–B27 does not guarantee that one may develop ankylosing spondylitis. 

• Environmental causes: Environmental factors can increase the risk of developing ankylosing spondylitis, but they are not clearly understood. Factors such as exposure to certain infections, toxins, and pollutants; injury to affected joints; changes in the colon bacteria; and bowel inflammation increase the risk of ankylosing spondylitis, but how these factors influence the onset and severity of ankylosing spondylitis is not understood.

• Race: Caucasians are affected more by ankylosing spondylitis compared to African Americans, which may be due to the prevalence of the HLA-B27 gene. This gene is present in 90 to 95 percent of Caucasian patients with ankylosing spondylitis. The prevalence of this gene is low in African Americans with ankylosing spondylitis. 

• Family history: Ankylosing spondylitis runs in families; that is, if a parent or sibling is diagnosed with ankylosing spondylitis, it is estimated that the patient is 10 to 20 times more likely to have ankylosing spondylitis than someone with no family history of the disease. 

• Inflammatory bowel disease (IBD): Having one disease can increase the risk of developing the other. Inflammation or swelling of the gastrointestinal tract is common in ankylosing spondylitis. Many recent studies have indicated that about 3 percent to 4 percent of patients with ankylosing spondylitis have inflammatory bowel disease. 

• Uveitis: It is a type of inflammation of the eye, and with one episode of uveitis, there is a greater risk of developing ankylosing spondylitis. According to a study of Arthritis Research and Therapy, uveitis occurs in about a quarter of patients with ankylosing spondylitis and is the most common manifestation of the disease outside the joints.
  

Ankylosing Spondylitis Complications

Ankylosing spondylitis is a complex disease which can affect different parts of the body. It can cause some serious complications, affecting day-to-day life and leading to additional health problems. Ankylosing spondylitis patients are at greater risk of thinning of the bones (osteoporosis), which can result in spinal fractures. The following are some of the complications of ankylosing spondylitis:

• Joint damage: In patients with ankylosing spondylitis, the hips and knees get inflamed, which over time can damage the affected joints, making them painful and difficult to move. Surgery may be required if the joint is damaged to replace the damaged joint with an artificial one. 

• Iritis: It is also known as acute anterior uveitis, a condition commonly associated with ankylosing spondylitis. In this condition, the front part of the eye becomes red and swollen, which usually affects only one eye, rather than both.

• Osteoporosis: It is a condition where the bones become weak and brittle, and it is a common and frequent complication of ankylosing spondylitis. In patients with ankylosing spondylitis, the inflammation of joints is associated with trabecular bone loss, which leads to osteoporosis. 

• Spinal fractures: In this condition, the progressive fusion of vertebrae causes the spine to stiffen, and as a result, the bones become prone to breaking even under minor traumas. Due to a weak spine, there is always a risk of spinal fractures. 

• Cardiovascular disease: Ankylosing spondylitis increases the risk of developing cardiovascular diseases, and this risk is multifactorial, including inflammation accelerating atherosclerosis and cardiac inflammation itself, such as in aortitis.

• Cauda equina syndrome: This is a rare complication of ankylosing spondylitis, which occurs when the nerves at the bottom of the spine become compressed (compacted). Severe weaknesses or numbness in both legs and numbness around the genitals are some of the symptoms of cauda equina syndrome. 

• Psoriasis: It is a commonly seen complication in patients with ankylosing spondylitis and is triggered by a skin break injury from vaccinations, sunburns, scratches, or other skin breaks.

• Inflammatory bowel disease (IBD): In patients with ankylosing spondylitis, there is always a risk of developing inflammatory bowel disease. This risk is because of the similar underlying mechanisms, which include an overactive immune system attacking healthy tissues in both the joints and the digestive tract.

Ankylosing Spondylitis Diagnosis

For diagnosing ankylosing spondylitis, a comprehensive evaluation of the entire body is suggested because of the disease systemic nature and its potential involvement with multiple organ systems. The following are the steps involved in diagnosing ankylosing spondylitis:

• Initial evaluation 
• Medical history 
• Physical examination

• Diagnostic evaluation 
• Laboratory testing 
• Complete blood count (CBC)
• C–reactive protein (CRP)
• Erythrocyte sedimentation rate (ESR) 
• Human leukocyte antigen B27 (HLA)   

• Imaging studies 
• X-rays
• Magnetic resonance imaging (MRI) 
• Ultrasound



• Genetic testing
  

Ankylosing Spondylitis Treatment

There is no cure for ankylosing spondylitis, and the treatment usually involves managing the symptoms and preventing further disease progression. The following are the steps involved in the treatment of ankylosing spondylitis: 

• Physiotherapy and exercise

• Drug therapy 
• Painkillers or Nonsteroidal Anti-Inflammatory Drugs (NSAIDS)
• Biologic therapy 
• Tumor necrosis factor (TNF) inhibitors
• Monoclonal antibody treatment
• Janus kinase Inhibitors (JAK inhibitors)

• Disease modifying antirheumatic drugs (DMARDs)

• Corticosteroids 

• Bisphosphonates

• Surgery
  

Ankylosing Spondylitis Prevention

There is no proven way of preventing ankylosing spondylitis. However, prevention of disease morbidity can be achieved with exercise, physical therapy, and tailored pharmacologic intervention.

Difference Between Dish and Ankylosing Spondylitis

Dish v/s ankylosing spondylitis

Both dishes (Diffuse Idiopathic Skeletal Hyperostosis) and ankylosing spondylitis (AS) are types of arthritis which affect the spine but differ significantly in their characteristics and causes. Dish is usually characterized by bone spurs and hardening of ligaments, while ankylosing spondylitis is an inflammatory condition that affects the sacroiliac joints and spine.

Difference Between Ankylosing Spondylitis and Rheumatoid Arthritis