Ankylosing spondylitis is a type of arthritis that affects the spine. Common symptoms include progressive lower back pain, fatigue, and pain that spreads to the shoulders, hips, and legs.

It is important to understand the early signs and symptoms of ankylosing spondylitis and how the condition progresses. This can help people know when to contact a doctor and what to expect from their diagnosis and treatment.

There is no specific diagnostic test for ankylosing spondylitis, and its slow progression can make assessment challenging. However, doctors can use a combination of symptom assessments, scans, and blood tests to confirm a diagnosis.

This article covers how ankylosing spondylitis affects the body and how doctors diagnose the condition.

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Ankylosing spondylitis is a type of arthritis that causes inflammation in the spinal joints. In some cases, it can affect the joints of the hips, shoulders, ribs, heels, and hands. It can also impact the eyes, heart, gastrointestinal tract, and lungs.

The condition can progress differently for every person who has it. The symptoms usually appear between the ages of 17–45 years, but they can sometimes begin in childhood.

Symptoms can include:

  • gradually evolving dull pain or stiffness in the lower back or buttocks that becomes chronic and lasts for longer than 3 months
  • pain that is worse in the morning and at night and interferes with sleep
  • low-grade fevers, loss of appetite, and general discomfort, especially during the early stages of the condition
  • pain that eventually spreads to the ribs, shoulders, thighs, hips, or heels
  • fatigue (low energy)
  • enthesitis, which refers to inflammation at a specific place where the ligament connects to bone
  • bowel inflammation that may be associated with conditions such as Crohn’s disease or ulcerative colitis
  • uveitis, or inflammation in the eyes
  • chest pain that may feel similar to a heart attack, and difficulty with deep breathing
  • arrhythmias that cause the heart to beat too fast or too slow
  • cardiomyopathy, a disease that weakens the heart muscle and makes it difficult for the heart to pump blood to the rest of the body
  • ischemic heart disease, which causes reduced blood supply to the heart

Some people develop more serious complications, such as aortitis. This causes inflammation of the aorta, which is the large artery that exits the heart. Ankylosing spondylitis can also lead to lung scarring or pulmonary fibrosis.

Advanced ankylosing spondylitis can cause jaw inflammation and neurological complications.

There is no single test to diagnose ankylosing spondylitis. Doctors often use X-rays, blood work, and MRI scans to find evidence of inflammation in key areas, such as the joint between the sacrum and the ilium.

Doctors also need to gather information about the type of back pain a person is experiencing. People with ankylosing spondylitis usually have symptoms before the age of 45 years, and their symptoms typically develop gradually over a period of 3 months or more.

People with ankylosing spondylitis also tend to experience back pain that gets worse while they sleep. It then starts to feel better once they move or take a warm bath or shower. The pain associated with ankylosing spondylitis does not usually ease with resting but tends to get better with exercise and physical motion.

Doctors often ask people if these situations apply to them and then move on to imaging to determine whether or not it is ankylosing spondylitis causing the symptoms.

There is also a blood test that looks for a gene called HLA-B27. Although having this gene does not mean that someone will definitely develop ankylosing spondylitis, it does appear in many cases.

Anyone who is experiencing symptoms of ankylosing spondylitis may benefit from visiting a doctor. The doctor may run tests or refer the individual to a rheumatologist for testing.

People who have received a diagnosis of ankylosing spondylitis, including those with minor symptoms that are manageable at home, should continue to see a rheumatologist at least once each year. Attending these checkups allows the rheumatologist to track the progression of the condition and to monitor for potential complications that may not be causing any symptoms.

Treatment for ankylosing spondylitis involves many different approaches designed to make the symptoms manageable. A typical treatment plan includes physical approaches such as exercise and physical therapy.

A doctor may suggest the person try nonsteroidal anti-inflammatory drugs (NSAIDs) to help ease the pain. Research suggests that NSAIDs may benefit people with ankylosing spondylitis because these medications can reduce the inflammation that causes the symptoms.

A doctor can also prescribe tumor necrosis factor inhibitors, which inhibit a protein that plays a key role in the inflammatory symptoms of ankylosing spondylitis.

Some people may also benefit from steroid injections.

In severe cases, a person may need surgery.

Since ankylosing spondylitis affects everyone differently, the outlook for people with the condition varies. Those with mild ankylosing spondylitis can expect to be able to continue functioning as usual. Other people may experience severe disability without effective treatment.

When ankylosing spondylitis causes life threatening complications such as inflammation in the heart, it may negatively affect a person’s life expectancy.

About 1% of people with ankylosing spondylitis experience remission.

Below are frequently asked questions relating to ankylosing spondylitis and its diagnosis.

What are the 3 most common symptoms of ankylosing spondylitis?

The three most common symptoms of ankylosing spondylitis are:

  • gradually worsening, dull lower back pain
  • lower back stiffness that may be worse on waking
  • pain that spreads to the hips, shoulders, and other joints

What can be mistaken for ankylosing spondylitis?

Ankylosing spondylitis shares symptoms with many conditions, and people may mistake it for

  • muscular lower back strains or sprains
  • rheumatoid arthritis
  • osteoarthritis
  • slipped discs
  • fibromyalgia
  • sciatica

What are the markers for ankylosing spondylitis?

The core diagnostic markers for ankylosing spondylitis include:

  • At least 3 months of lower back pain that doesn’t improve with rest.
  • Clear inflammation of the sacroiliac joints in X-ray or MRI scans.
  • The presence of the HLA-B27 gene in blood tests.
  • The presence of inflammatory markers such as C reactive protein and erythrocyte sedimentation rate in blood tests.

Ankylosing spondylitis is a type of arthritis that affects the spinal joints. It primarily causes pain and stiffness throughout the body, but it can also affect other body parts and organs.

It is important for people with ankylosing spondylitis to follow their treatment plan and to regularly contact a doctor or rheumatologist to check on the progression of any symptoms. Doing this provides the best chance of managing the symptoms and slowing the condition’s progression.