Friday Facts! Juvenille Myositis

Welcome to Friday Facts! here on the Knowledge Safari blog. Each week we aim to shine the spotlight on various segments of special needs in order to raise awareness and provide information. Today we focus on Juvenille Myositis.

I first learned of this disease through a great blog called Dad Centric.

The following is taken from and you can read more at: Cure JM Foundation

What is JM?

Juvenile Myositis (JM), including Juvenile Dermatomyositis (JDM), Amyopathic Dermatomyositis (AMD) and Juvenile Polymyositis (JPM), is an autoimmune disease affecting approximately 5,000 children in the United States. Weak muscles and skin rash are the primary symptoms of JDM, while muscle weakness without a rash is the primary symptom of JPM. Children afflicted with AMD, on the other hand, experience the skin rash without the weakened muscles. Even within these three designations, JM affects every child differently. Some children experience a mild form of the disease, while others follow a more severe and potentially more debilitating course. Some of the more onerous secondary symptoms are calcinosis, vasculitic ulcers and contractures.

Genesis of the Disease

The immune system is a group of cells that normally protects the body from infection. In autoimmune diseases like JM, however, once these cells turn on their infection-fighting process, they cannot turn it off. This process therefore damages the body instead of protecting it.

One way the immune system cells fight infection is through inflammation. But when the cells cannot turn off the inflammation process, tissues are damaged. In JM sufferers, the skin rash and weak muscles are caused by vasculitis, an inflammation in the blood vessels that lie under the skin and in the muscles. Since blood vessels run throughout the human body, JM can also affect other systems such as the digestive tract.

What causes JM?

Many researchers believe that there is a genetic predisposition to autoimmune diseases. As such, they feel that a child afflicted with JM is likely to have a blood relative who suffers from another autoimmune disease such as diabetes or arthritis.
The autoimmune disease initially presents itself when an invasive "trigger" causes the body's immune system to overreact. It is believed that this trigger could be a virus, a vaccine or an environmental hazard.

What are the symptoms of JM?

The primary symptoms of JM are weak or painful muscles, skin rash (with JDM), fatigue and fever. Some children experience joint pain as well.
Weak muscles The muscles that are affected the most are near the trunk of the body: the stomach, quadriceps, neck and biceps. However, other muscles can become weak as well. Sometimes there is inflammation in the esophagus which makes it difficult for the child to swallow. Other times, there is inflammation in the gastrointestinal tract, which causes bowel difficulties.

A child with JM has great difficulty climbing stairs and getting up from the floor or from a chair. Walking and running become very challenging and exhausting.

Skin rash. The skin rash in JDM usually occurs on the face, knuckles, elbows, knees and ankles. The rash may appear before, after or at the same time as the muscle weakness. Sometimes the rash is so faint that it is not noticeable.

The rash appears as a red purplish color on the eyelids and cheeks; whereas the rash looks like red dry skin patches over the knuckles, elbows and knees. The fingernails and the nailbeds may take on a pinkish color as well.

Sometimes, the children develop Gottron’s Papules, which are small whitish bumps that appear on the fingers. They look like small blisters.

To view examples of these rashes, click here.

Fatigue With JM, the child becomes tired easily and can only walk short distances. The child needs to rest often and lacks the energy for normal activities. It becomes difficult for the child to keep up with friends.

Fever Oftentimes, the child with JM runs low-grade fevers, especially at night. There has also been a connection discovered between a virus with high fevers just before the onset of JM.
What are other possible symptoms? The following symptoms of JM are less common, but important to understand:

Calcinosis About a third of the children with JM will develop calcinosis, which are small lumps of calcium that form under the skin or in the muscle. They may feel like little rocks under the skin and can range in size from a dot to a large pebble.

The lumps can either break through the skin and form a bump that may leak creamy white calcium, or they can be absorbed back into the body. If they break the skin, they can become infected and painful, and sometimes need to be surgically removed. They usually occur on the joints, such as the elbows and knees, but they can occur anywhere on the body.

Vasculitic Ulcers Vasculitic ulcers are holes in the tissue that surrounds an inflamed blood vessel. They can occur in the skin or in the bowels (the organs that transport food from the esophagus to the rectum).

When they occur in the skin, they look like sores in the skin rash. They can be very deep or on top of the skin and they also range in size. The ulcers can be very painful, but will usually go away with treatment.

When the ulcers occur in the bowels, it is due to inflamed blood vessels in the protective lining around the bowels. They cause a break in the lining which can eventually harm the digestive organs.

The warning signs of this condition are severe stomach pain, dark black stools or blood in the stools, or a change in the pattern of bowel movements.

Contractures Contractures are shortened muscles that cause a joint to stay in a bent position. These can occur due to lack of exercise or from scarring of the muscles.

What tests are used to diagnose JM?

If JM is suspected, blood tests are the first step to confirm that there is a problem. Muscle enzymes are measured, including CPK and aldolase, which are enzymes that leak from inflamed or damaged muscles into the bloodstream. Antinuclear antibodies (ANA) are also measured to see if the child’s body is producing antibodies against its own cells.

The next step is usually an MRI which can also detect muscle damage and inflammation. If the MRI shows evidence of diseased muscles, a muscle biopsy is typically performed to finalize the diagnosis. A small amount of muscle is removed for examination to determine if and how much the muscles and blood vessels have been affected by the disease.

What is the treatment for JM?

There is no cure for JM yet, but there are treatment options to help manage the symptoms. Early and aggressive treatment is usually the best predictor of a better outcome of this disease.
IV corticosteroids (Solumedrol) are usually the first line of treatment for JM. This is oftentimes coupled with high dose oral Prednisone, another corticosteroid. Since the side effects of corticosteroids can be very troublesome, Methotrexate (a chemotherapy drug when given in higher doses) is usually introduced early to allow for tapering of the corticosteroids.

Other common treatments include Cyclosporine and Intravenous Immunoglobulin (IVIG). Less common treatments, but still used include Cellcept (chemotherapy), Enbrel and Remicade.
These medications all have their own side effects, but the most common ones for Prednisone are: -increased appetite and weight gain -rounded face -mood changes -high blood pressure -stretch marks -fragile bones and bone damage -cataracts -slow growth

What is the prognosis?

It is believed that a third of the children will suffer from JM most of their life, while another third will experience temporary remissions and the other third will experience a permanent remission (no medications, no symptoms).