Juvenile ankylosing spondylitis (JAS) is a type of arthritis. It affects the spine and the places where the muscles, tendons, and ligaments attach to the bone. JAS affects boys more than girls. It usually happens before 16 or 18 years of age. JAS is a long-term (chronic) condition. Some people will have periods of time where the disease is not active or mild (remission). Others will have ongoing symptoms.

ANG-kuhl-oh-sihng

spawn-duh-LI-tihs

Researchers don't know the exact cause of JAS. It tends to run in families. A gene marker called HLA-B27 is found in many people who have the disease. But only a very small number of people with the marker will develop the disease. Because of this, researchers don't fully know if the gene marker increases the risk for the disease.

Symptoms can happen a bit differently in each child. They tend to come and go over time. Symptoms can include:

• Pain in the back, joints, buttocks, thighs, heels, or shoulders.
• Early morning stiffness that gets better with activity.
• Trouble standing up straight.
• Trouble taking a deep breath.
• Loss of appetite.
• Weight loss.
• Tiredness (fatigue).
• Fever.
• Eye pain, redness, and sensitivity to light.
• Symptoms of inflammatory bowel disease such as belly pain or diarrhea.
• Skin problems such as a rash or painful bumps.

Because the symptoms of JAS are like those of other conditions, JAS can be hard to diagnose. The doctor will ask about your child's symptoms and health history. They may also ask about your family's health history. They will give your child a physical exam. Your child may also have tests such as:

• X-rays. This test uses a small amount of radiation to create images of tissues in the body. X-rays may show changes in the spine and joints. Changes may not show up in the early stages.
• Other imaging tests. Other tests that create images of the body may be done. This may include MRI. This test uses large magnets and a computer to create images of tissues in the body.
• Blood tests. There are no specific tests for JAS. But general blood tests may be done such as:
  • Erythrocyte sedimentation rate (ESR or sed rate). This test is done to see if there is inflammation in the body. A child with JAS may have a high ESR level, but this can also have other causes.
  • HLA-B27 antigen test. This blood test is for some autoimmune conditions. HLA-B27 is an antigen. If this antigen is in the blood, it may mean your child has a type of autoimmune disease. Like the ESR, the test result isn't specific to JAS. The test results may have another cause.

The diagnosis of JAS can be difficult. Your child's doctor may advise that your child be seen by a doctor who specializes in joint diseases (rheumatologist).

The goals of treatment for JAS are to:

• Reduce pain and stiffness.
• Prevent deformities.
• Help your child be as active as possible.

Treatment will depend on your child's symptoms, age, and general health. It will also depend on how severe the condition is. Treatment may include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, to reduce pain and inflammation.
• Short-term use of corticosteroid medicine to reduce inflammation.
• Disease-modifying antirheumatic drugs (DMARDS) and targeted synthetic DMARDs to slow down inflammation in the body.
• Biologic medicines such as infliximab or etanercept to slow down inflammation in the body.
• Regular exercise, including exercises that strengthen back muscles.
• Physical therapy and assistive devices.

Talk with your child's ddoctor about the risks, benefits, and possible side effects of all medicines.

Early diagnosis and treatment are important to reduce or delay complications. Possible complications of JAS include:

• Joint damage.
• Bones of the spine and chest that grow together (fuse).
• Abnormal forward curve of the spine (kyphosis).
• Trouble breathing because of changes in the spine and chest (restrictive lung disease).
• Breaks in the bones of the spine.
• Heart, lung eye, and kidney problems.
• Poor growth.

JAS is a long-term (chronic) condition. Some people will have periods of time in which the disease is not active or mild (remission). Others will have ongoing symptoms.

Help your child:

• Stay as active as possible.
• Balance activity with rest.
• Eat a healthy diet.
• Use good posture to help ease pain and stiffness.
• Find a support group, therapist or psychologists to help them learn positive coping strategies and deal with emotions.

Also make sure your child stops smoking, vaping, or using other tobacco or nicotine products, or never starts. Smoking has been linked to having more problems with JAS.

Work with your child's care team to create an ongoing treatment plan that's best for your child.

Contact the doctor if your child has any of these:

• Eye symptoms
• Other new symptoms
• Symptoms that get worse

If your child has trouble breathing, call 911.