What are the first signs of ankylosing spondylitis?

What is ankylosing spondylitis?

Ankylosing spondylitis (AS) is an inflammation of the joint that primarily affects the spinal joints. Occasionally the hip and shoulder joints are involved too. It typically occurs in young men in their 20s and affects about 0.5% of the adult population. Studies have shown, however, that the prevalence is as high as 5% among those who are HLA-B27 positive. Like many other autoimmune diseases, AS has a clear genetic factor. HLA-B27 can be demonstrated as one of the ankylosing spondylitis tests, but its presence is not diagnostic of AS. The exact cause of AS is still unknown as only a small percentage of individuals with the gene contract the disease. To date,  there is no cure. The treatment aims to improve the quality of life by relieving symptoms, maintaining daily functions and preventing complications. Treatments include analgesic medications, physiotherapy, lifestyle changes and surgery.

What are the symptoms of ankylosing spondylitis?

  • Low back pain and neck pain
  • Back stiffness
  • Mild fever and fatigue
  • Loss of appetite
  • Alternating buttock pain
  • Pain at other joints like ankle, knee, shoulder, rib cage and jaw
  • Painful eye (uveitis is associated with ankylosing spondylitis)
  • Movement and breathing difficulty (later stage)

The predominant symptom of ankylosing spondylitis is chronic severe back pain which is inflammatory in nature. The inflammatory arthritis pain is often described as sudden in onset, improves with exercise but worsens with rest. The pain may be felt at night. Upon waking up from sleep, the back feels stiff for at least 30 minutes. As the day goes on, the body loosens up and feels better. Other joints may hurt like the ankle, knee, shoulder and jaw. You may also feel tired and general discomfort as it is exhausting for the body to fight inflammation. Some people have associated painful eyes in the early stage of disease.

In medicine, the terminology of signs are not the same as symptoms. Symptoms are the patient’s perceptions of the disease, while signs are the objective manifestations of the disease that are detected by doctors during examination. The following are the signs of ankylosing spondylitis.

  • Weight loss
  • Abnormal postural like hyperkyphosis (hunchback)
  • Impaired spinal mobility
  • Flexion deformity of the hip
  • Peripheral arthritis (inflamed joints at the ankle, knee, shoulder, rib cage and jaw)
  • Enthesistis (inflamed enthesis, the region of attachment of ligament and tendon to bone)
  • Dactylitis (inflamed toes and fingers)
  • Reduced chest expansion

As ankylosing spondylitis is a systemic disease, it can affect other parts of the body. 35% of individuals with AS have concomitant acute anterior uveitis (inflammation of the eye) that presents as painful eyes, blurry vision and photosensitivity. Besides that, AS is also associated with inflammatory bowel disease (IBD), psoriasis and increased risk of cardiovascular diseases such as heart attack and strokes. Only a minority of people have symptomatic IBD like abdominal pain and diarrhoea. Psoriasis is present in 10% of the cases, with symptoms like rashes and dry, scaling skin.

The first signs of ankylosing spondylitis are weight loss, abnormal posture and impaired spinal mobility. Another early sign of AS is uveitis. Early on, individuals would complain of constant back pain and stiffness, with fatigue, reduced appetite and weight loss. Gradually, the abnormal posture, especially hyperkyphosis (hunchback), becomes apparent as early as within the first 10 years of the disease. As the disease progresses, the bone fuses (ankylosis) and causes immobile joints. The typical stooped posture becomes more prominent, further restricting movement. If the rib cage bones are affected, the expansion of the chest and lungs may be compromised, causing breathing difficulty. Complications may also occur like spinal bones that fracture easily due to rigid bones and osteoporosis.