Unmasking the Mystery of Myositis
Date: September 1, 2007
Myositis is a painful, debilitating muscle disease in which the immune system attacks healthy muscle tissue. Its chief symptom is muscle weakness, but because it so closely resembles other diseases, it’s difficult to diagnose. In fact, most patients see as many as six doctors, on average, before they get a proper diagnosis.
Tamika Moore’s primary care doctor believed she had liver disease. The 26-year-old physical therapist on staff at Johns Hopkins was inexplicably weak; a blood test had showed elevated liver enzymes. A gastroenterologist scheduled her for a liver biopsy. A second blood test, though, showed abnormally high amounts of the muscle enzyme creatine kinase, an indicator of muscle disease.
Moore’s next stop? The Myositis Center where specialists in muscle disease, including neurologists, rheumatologists and a pulmonologist treat adults with all forms of the disease: polymyositis, which sometimes affects the lungs; dermatomyositis, which is often accompanied by a skin rash and is linked to a high rate of cancer; and inclusion myositis, an inherited form of the disease.
Patients undergo a battery of tests, most often electromyography (EMG) to assess the health of the nerves controlling the muscles, muscle MRI, CT scans, and pulmonary function tests. All can usually be done in one visit.
Patients are treated medically with drugs, especially corticosteroids. “A significant fraction go into remission. A second group continues treatment with some sign of disease. A third group,” says center co-director Andrew Mammen, “is difficult to help, but you keep trying.”
Center co-director Lisa Christopher-Stine is collecting clinical, serologic, imaging and pathologic information from large numbers of patients to help determine optimal treatments. “Now,” says Mammen, “we have a grab bag of medicines, but we can’t predict which patient will be most helped by which medicine.”
One of the center’s strengths is that it is jointly led by a neurologist, Mammen, and a rheumatologist, Christopher-Stine. “That’s unusual because with autoimmune disease, neurologists and rheumatologists don’t always see eye to eye,” says Mammen. “Neurologists think rheumatologists are poor at diagnosis; rheumatologists think neurologists are poor at using medicines to treat immuno-supression. Lisa and I, though, have none of those hang-ups. We’re learning from one another.”