Juvenile Dermatomyositis (JDM)

Juvenile Dermatomyositis (JDM) is an idiopathic inflammatory myopathy of presumed autoimmune dysfunction. The autoimmune response of the body causes an inflammatory response in the body’s tissue. In this particular disease, the immune system attacks the body’s blood vessels. Children suffering from JDM suffer from muscular weakness, particularly in the shoulder and pelvic areas. They also suffer from facial rashes and rashes on the fingers, knees and elbows.

JDM is relatively rare among children, occurring in only 4:100,000. It is two times as likely to affect girls as boys. It is generally diagnosed between the ages of 4 and 10.

What causes the Juvenile Dermatomyositis? Is it hereditary? Can it be prevented?
Like most autoimmune diseases, the causes behind JDM are unknown. Most likely, the disease is caused by a number of factors. This means that a lack of specific factors raises the child’s chances of developing the disease. The disease is not hereditary. Since the cause is still unknown, there is no cure. JDM is not contagious.

The disease is characterized by muscular weakness, which manifests as fatigue, joint and muscle pain and limited mobility. Some children also experience swelling in the joints. The skin rashes can appear either before or after the muscle weakness. The rashes are similar to eczema with a distinct color – heliotrope. The rashes generally appear on the joints – knees, elbows and ankles. It tends to get worse with sun exposure. Other rashes appear on the face – around the eyes, eyelids and cheeks.

Practically this means that your child will probably not be able to walk to school or participate in sports. Smaller children may ask to be carried. As the disease progresses, getting out of bed and climbing stairs becomes difficult. Some children develop contractures, where the muscles shorten and the joints stay bent. In the future, calcium may sink under the skin and create nodules. These nodules are at risk of getting infected, causing ulcers and excreting fluids. Voice changes, difficulty eating and swallowing, coughing and shortness of breath are indicators of this disease development and should be taken very seriously.

Digestive system dysfunction includes stomach pains, discomfort and constipation. In rare cases, blood vessels leading to the intestines get clogged and can exacerbate the problem.

The disease manifests itself differently among children. There is a broad spectrum, ranging from barely discernible dysfunction to severe and painful. Different organs and body systems are involved. Children suffering from a severe manifestation of the disease suffer from multi-system involvement, which includes the skin, muscles, lungs and intestines.

For adults, dermatomyositis can develop as a metastasis, but not for children. Muscular involvement is more common among adults, while this is a rare manifestation among children.

Diagnosis of Juvenile Dermatomyositis
The diagnosis is based on clinical symptoms, as described above, together with a lab test. At the onset the disease may seem similar to lupus, arthritis, vasculitis or others. The severity of the muscular dysfunction is measured by testing the strength of the muscles in the different organs. In most cases, affected muscles leak vital substances into the blood. The most important are proteins called CPK. Blood tests are also used to monitor the disease and treatment progress. In certain cases, the doctor may need to perform an EMG (electromyography) test. This test helps the doctor determine the changes in the muscles’ functionality. Biopsies are also an important tool which is used in order to confirm a diagnosis. To estimate the extent of muscular involvement, doctors may also perform EKGs, Heart Echos, chest x-rays or CT scans.

In typical cases children will experience proximal muscle weakness and skin rashes. For these cases, doctors can diagnose the disease based on these symptoms alone. Tests are only done afterwards to confirm the diagnosis.

Is there a cure for JDM?
JDM is a treatable disease. The drug treatments help control the disease until it goes into remission. Treatment is personally suited for each child. If the disease is untreated or untreatable, it may cause irreparable damage to the child. For many kids, physical therapy and psychological support are extremely helpful.

Treatments for JDM

Steroids help control the infection. They act quickly when injected into the vein. They act faster than any other type of medicine, and can be lifesaving. Steroids cause side effects, and therefore doctors try to treat the infection with other types of drugs. Side effects include developmental problems, higher risk of infection, high blood pressure and osteoporosis. The side effects depend on the dosage administered – the lower the dose, the fewer side effects it causes. Additionally, steroids suppress the release of the body’s naturally-produced steroids, which can cause fatal problems if steroid treatment is stopped abruptly. Steroids must be gradually stopped.

Steroid treatment is generally combined with other drug treatments, such as methotrexate or cyclosporine. These medications help keep the disease in remission and allow a lower dose of steroids.

Methotrexate is a drug that takes 6-8 weeks to begin working. In most cases, it is administered over a long period of time. Its main side effects include nausea, oral ulcers, some hair loss and liver problems. Its effect on the liver is minimal, but gets worse when combined with alcohol. It is dangerous to fetal development and should not be taken during pregnancy.

Similarly to methotrexate, it is also administered for a long period of time. It causes a number of side effects, including high blood pressure, and kidney problems.

If the infection does not respond to any of these treatments, there is an indication for tougher drugs, such as azathioprine or cyclophosphamide. Using new, biological treatments is still in the trial stage.

Physical Therapy
Common symptoms of JDM include muscle weakness and joint pain. This can be treated with physical therapy sessions. The therapist will teach your child how to perform a number of exercises which will strengthen their muscles and release their joints. Your job as a parent is to encourage your child to perform his exercises.

The length of the treatment depends on the child. There are some children whose infections are short-lived, while others suffer from the disease for years. The treatment goal is to control the disease and it is stopped after symptoms disappear. The disease is ‘sensitive’ to the gradual lessening of the dosage, and your child may experience an outbreak if the doses are lowered too quickly too fast.

Alternative Therapeutic Approaches
Many times patients are offered unconventional treatment methods which have not been scientifically proven to be efficient. If you are interested in an alternative treatment method, speak to your child’s pediatrician. Most doctors will not object.

It is extremely important to monitor the disease and side effects. This should include evaluation of muscle strength, blood tests, and side effects.

If the disease gets under control, the prognosis is good. However, there is still a chance that the disease will prove fatal (if there is respiratory, cardiac, nervous or digestive involvement). Functionality is also dependent on the calcium nodules and how severely the muscles are affected.

The disease is generally divided into three main categories:

  • JDM with a relatively short active infection. Only one system is affected. Good prognosis.
  • Recurring chronic disease – disease comes and goes based on treatment.
  • Active chronic disease – the disease is active despite treatment.