Juvenile Myositis

Juvenile myositis is a rare, childhood autoimmune disease that primarily causes inflammation in the muscles, skin and blood vessels. The inflammation leads to weakness in the muscles and rashes on the skin.

The most common type of juvenile myositis is juvenile dermatomyositis, or JDM, which is characterized by specific rashes. There are other forms of juvenile myositis that are even more rare, such as polymyositis, which do not have characteristic rashes. Other autoimmune diseases can cause myositis too.

Why choose Mott for juvenile myositis care

The Juvenile Myositis Clinic at Mott provides a multidisciplinary clinical approach to bring excellence in care to all children with juvenile myositis. Our care team includes:

  • pediatric rheumatologists
  • pediatric rheumatology nurse
  • pediatric physical therapist
  • pediatric dermatologist
  • pediatric psychologist

The clinic occurs the second Tuesday of every month on the 8th floor of the C.S. Mott Children’s Hospital Outpatient Pavilion.

Our juvenile myositis team is part of the Cure JM Clinical Care Network, one of only 15 centers in the country to be recognized for this specialized care.

We aim to create an environment where patients, families and clinical care staff work together to best meet individual patient care needs. We engage patients and families in determining key priorities and expectations for care through our Patient and Family Advisory Council (PFAC) and support patients and families through our Peer Mentor Program. We also integrate opportunities for research participation along with clinical care visits and have ongoing studies to learn more about differences in the immune system that might cause juvenile myositis and how to predict outcomes and best treatments.

Symptoms of juvenile myositis

The most common symptoms of juvenile myositis include muscle weakness and skin rashes. Muscle weakness occurs more often in muscles closer to the body trunk (thighs, upper arms, abdomen, neck) and can cause difficulty with day-to-day activities, such as going up the stairs, lifting the arms or decreased play activity. There can also be accompanying muscle pain.

Skin rashes most specific to juvenile myositis occur over the joints, particularly the knuckles, and around the eyes, although they can occur in other places as well. Rashes are often sensitive to sunlight.

Juvenile myositis affects every child differently and can also cause symptoms in other organs, including the lungs, stomach, intestines, heart and joints.

Diagnosing juvenile myositis

To make a diagnosis of juvenile myositis and characterize where there is inflammation in the body, it is important to perform a detailed physical exam along with blood tests and potentially imaging, biopsy and other functional studies. These help to rule out other potential diagnoses that can cause similar symptoms and that would be treated differently. Testing may depend on the child’s specific symptoms. No one test is generally enough to diagnose the disease; therefore, a comprehensive assessment is needed to appropriately evaluate, understand and treat the cause of your child’s symptoms.

Examples of evaluations and testing that may be performed include:

  • Clinical history: Your child’s doctor will ask questions about their symptoms, any medications they take, their medical and family history, and any recent infections.
  • Physical exam: Your child’s doctor will perform a comprehensive clinical exam, test their muscle strength and examine any rashes.
  • Physical therapy evaluation and assessment: Our physical therapist will ask about and assess any musculoskeletal concerns and perform standardized muscle testing.
  • Nailfold capillaroscopy: A member of our care team will use a camera with a microscope to non-invasively view and assess any changes to the small blood vessels located beneath the nailbeds.
  • Blood tests: Used to evaluate for other potential causes of symptoms and test for inflammation in other organs. This helps understand the degree of inflammation in the body and characterize the presence of autoantibodies (antibodies that mistakenly target and react to tissues and organs) that can be found in myositis and other autoimmune diseases.
  • Imaging: Used to evaluate for muscle inflammation. Most commonly, Magnetic Resonance Imaging (MRI) of the thighs is obtained.
  • Biopsy: Sometimes muscle biopsy is performed to definitively diagnose juvenile myositis if there is not presence of other typical features, such as rash, or if we need to rule out other types of muscle diseases. A skin biopsy is also sometimes performed if we need more information about your child’s rash to assist in a diagnosis.
  • Functional organ testing: Used to evaluate your child’s heart, lungs and swallowing muscles. This includes an echocardiogram (ECHO), pulmonary function testing (PFTs) and a swallow study.

Children with myositis can sometimes have clinical symptoms or exam findings of other autoimmune diseases such as lupus or scleroderma, and may have mixed connective tissue disease (MCTD) or overlap myositis. As more research is being done on juvenile myositis, we are learning about different types of myositis in children.

Treatments for juvenile myositis

Our care team provides comprehensive treatment for juvenile myositis patients, which includes:

  • taking medicines that modify the immune response
  • participating in physical therapy and exercise to improve muscle strength and function
  • using sun protection
  • assessing mental and behavioral health

Immunomodulatory treatment: Most patients are treated with immunomodulatory medications to decrease inflammation in the muscles, skin and other involved organs. Medications can be given by mouth, under the skin (subcutaneous injections) or via intravenous (IV) therapy in the infusion center. Most patients are started on a similar standardized treatment plan at diagnosis, but medicines prescribed will depend on how severe the disease is and which organs are involved. Commonly prescribed medications at time of diagnosis include steroids (oral and IV), methotrexate (oral or subcutaneous injections), hydroxychloroquine and intravenous immunoglobulin (IVIG). Not all children with juvenile myositis respond fully to these initial therapies, and we sometimes treat with other disease modifying antirheumatic drugs (DMARDs) such as mycophenolate mofetil or biologic medications such as rituximab, tofacitinib, abatacept, adalimumab and infliximab.

Topical therapy: Our team’s pediatric dermatologist will evaluate all skin rashes, prescribe topical treatments as needed and provide expert care for juvenile myositis patients with persistent skin disease.

Physical therapy and exercise: Physical therapy and activity are an integral part of the juvenile myositis treatment plan and are necessary to help regain muscle strength and function after weakness. Our team’s physical therapist will perform detailed muscle testing at each visit and provide recommendations for continued outpatient therapies if needed.

Mental health assessment and treatment: Our team’s pediatric psychologist will provide assessment and treatment of mental and behavioral health concerns commonly associated with chronic illness.

Long term outlook for juvenile myositis

Juvenile myositis is a chronic condition that affects all children differently. Some children will go into remission after starting therapy and be able to go off all medications and treatments within a few years. Other children with juvenile myositis follow a more chronic disease course and will need to stay on long-term treatments. Once we control symptoms and muscle inflammation, patients can participate in regular childhood activities and lead active lives.

Research and improving care for juvenile myositis

A Mott, we believe that integration of research with clinical care is important to improve quality of life and outcomes for children with juvenile myositis, engaging patients and families in generation and development of research projects.

There are multiple ongoing research projects aimed at:

  • learning more about what causes juvenile myositis and how it relates to other pediatric autoimmune disease
  • developing better markers to monitor and predict disease course and treatment response
  • identifying new treatment options

Mott also participates in multicenter and collaborative research projects with other juvenile myositis centers, currently leading a multicenter research project to understand ways to predict which patients will respond to standard therapy and which patients might need different treatments earlier in the disease course. And, as a participating center in the CARRA Registry (Childhood Arthritis and Rheumatology Research Alliance), Mott joins the nation’s network of leading rheumatology providers working to improve care and treatment for children with rheumatic diseases.

Next step

To learn more about juvenile myositis or to schedule an appointment, please call 734-764-2224.