Ultrasound for Myositis

Early stage myositis often affects the hips and shoulders.

Myositis is a rare and painful immune disease, in which the body's own natural defenses attack healthy muscle tissue, causing inflammation. This disease may take several forms, and usually takes a long time to develop. It may appear in people of any age. The first signs of myositis include pain and weakness in the hips and shoulders. Unfortunately, this condition may be hard to detect. Ultrasound is one tool which helps doctors accurately determine whether or not a patient has myositis.

Myositis

While myositis is incurable, prompt treatment early in the disease can help reduce its long term effects. Untreated myositis can eventually weaken the muscles of the chest and lungs, or make it difficult for sufferers to swallow. Early detection can help myositis patients get the correct treatment early, and help them manage their symptoms effectively.

Ultrasound

Ultrasound is readily available and easy to use. It offers a high resolution scan and real-time imaging, without the need to expose the patient to ionizing radiation, unlike a CT scan. According to Medscape Today, ultrasound can detect myositis in a significant percentage of myositis cases and is much less expensive than other techniques.

Effectiveness

Ultrasound provides reasonable effectiveness at detecting myositis when compared to other techniques. According to Medscape Today, muscle ultrasound is about 83 percent effective, while electromyography is about 92 percent effective. Checking levels of creatine kinase, a muscular enzyme, is effective only about 69 percent of the time. Ultrasound is not always as effective at determining the specific type of myositis, however.

Expert Insight

According to the National Institutes of Health, a study originally published in the Journal of Neurological science found that ultrasound was effective both in determining the presence of myositis and establishing its absence. Ultrasound was able to positively predict myositis in a little over 95 percent of cases, was able to disprove myositis in slightly more than 89 percent of cases and was 91 percent accurate over all. Ultrasound helped improve clinical assessment of myositis patients by telling doctors where the muscles were abnormal.

Considerations

Ultrasound is most effective at detecting myositis with the use of high frequency probes, but in some cases, such as large patients with deep abnormalities, low frequency probing may be appropriate. The ultrasound can also detect the extent and type of muscle damage and may be more effective at detecting certain problems than an MRI. However, it is not the right tool for every case. Not all myositis cases are detectable by ultrasound and some of the information provided by this process is too unspecific to be useful.

References

• American Academy of Orthopaedic Surgeons: Myositis
• National Institutes of Health: Muscular ultrasound in idiopathic inflammatory myopathies of adults
• MedScape Today: Imaging Tools for the Assessment of Idiopathic Inflammatory Myositis: Ultrasound
• Imaging: Ultrasound of muscle