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Magill’s Medical Guide, 9th Edition

Polymyositis

by Leah Jacob

Category: Disease/Disorder

Anatomy or system affected: Muscular system

Specialties and related fields: Rheumatology

Definition: Polymyositis is an idiopathic disease of muscle inflammation. Myositis is the general category for inflammatory muscles diseases such as juvenile myositis, dermatomyositis, inclusion body myositis, and polymyositis. Referred to as inflammatory myopathies, the muscle inflammation can cause damage to the muscles. Referred to as inflammatory myopathy, the muscle inflammation can cause damage to the muscles. Polymyositis is considered to be an autoimmune disease. It can occur in persons of all ages, but is most common in middle childhood and in the twenties. Polymyositis is more common among women and girls. There are twice the number of cases in women than in men and boys. When the inflammatory condition of polymyositis is seen on the skin as well, this is termed dermatomyositis. The disease does not manifest immediately; rather, there is a gradual process of weakness over a three-to six-month period. Typically, there are remissions and exacerbations.

Key terms:

autoimmune: An autoimmune condition that is caused by the person’s immune system. In this situation the immune system has failed to delete the T cells that are not recognizing “self ” versus “non-self ” dysphagia: having difficulty swallowing due to muscle weakness

prognosis: the estimated good life or survival time as assessed by your physician

CAUSES AND SYMPTOMS

The main feature of polymyositis is the inflammation and the damage to the muscles that ensues. The person with polymyositis has white blood cells in the affected muscles. The inflamed muscles, caused by the disease, tend to release enzymes into the bloodstream. So, lab tests of the blood will demonstrate high levels of muscle enzymes. The muscles close to the trunk or torso are the main muscles affected. Usually there is symmetrical muscle weakness. Both the lungs and the heart can be affected by this condition. Problems in the lungs can cause dysphagia, shortness of breath, and infection. Heart problems are a little less common and can be a bad sign.

The primary symptom is the debilitating weakness, although it usually does not cause pain. There is a possibility that muscles of the body further away from the trunk can also become affected by the disease; if this occurs, it may only happen when there is a disease progression.

The disease may not be easily identified at first. Joint pain or weakness may be experienced as a general feeling of fatigue and exhaustion. Rising off a chair may be challenging as is the movement of raising one’s arms to perform a simple action. Climbing stairs or lifting objects may feel extremely difficult or impossible. Likewise, when lying down, a person may find it difficult to get up. The weakness is felt in the torso or core area. Muscles of the hips, thighs, and shoulders are usually affected. Sometimes muscles may ache, and the body may be sensitive to touch. Dysphagia may occur, with the person finding it difficult to swallow. Further symptoms may include fever and weight loss. A skin irritation may be seen, such as a rash around the eyes (red or violet), on the knuckle area of the hand, on elbows, knees, neck, and chest. Some researchers think that polymyositis may be inherited. It appears that if a patient’s family members have had neuromuscular problems, that the polymyositis may be inherited. It is also thought that it may be caused by a virus, such as cytomegalovirus.

TREATMENTS AND THERAPY

The polymyositis diagnosis is verified by a series of tests. Following a full physical examination by a doctor, the patient will be sent for blood tests. Further testing may be conducted to ascertain the state of the nerves and muscles. The most critical tests are EMG (electromyography) and an MRI (magnetic resonance imaging) of the muscles affected, and a muscle biopsy. The blood test may demonstrate a high level of muscle enzymes, a CPK, and liver enzymes. Further testing may be conducted to ascertain the state of the nerves and muscles. There is also the theory that the person may have another autoimmune disease with similar symptoms.

Medications for polymyositis may comprise a number of prescriptions. The primary medication consists of immune system suppressants. Corticosteroids are typically prescribed, particularly as the first option to treat the illness. Their effectiveness relates to the ability to reduce muscle inflammation. When corticosteroids are not found to improve the condition, specialists may prescribe immunosuppressive medications. Medicines of this type include methotrexate, azathioprine, cyclosporine, tacrolimus, chlorambucil, mycophenolate, cyclophosphamide, and rituximab. If the symptoms are particularly debilitating the physician may put the patient on an infusion of immunoglobulins (IVIG).

Because of the muscular effects of the disease, doctors usually recommend a course of physical therapy to accompany medical treatment.

PERSPECTIVE AND PROSPECTS

The cause of polymyositis remains elusive despite constant research. There is a possibility that hereditary factors may be responsible for polymyositis. As research continues and develops more insight into the immune system and related diseases. The hope is that understanding of the immune system and its functioning will facilitate deeper knowledge, and disease causes. There is a good prognosis for people who develop the disease in its early stages. Current research has revealed so far that immune system cells appear to invade muscle tissue at the onset of the disease, continuing to attack the muscles and causing damage. There is a good prognosis for people who develop the disease in its early stages. Possibilities of the disease becoming inactive happen often. In these instances, the process of rehabilitating the muscles can occur with beneficial results. Exercises to prevent the wasting away of unused muscles will be implemented with the aim of strengthening the affected and surrounding muscles.

Following are some organizations related to Polymyositis. In the United States, there are a number of organizations or associations providing information or support regarding muscle diseases such as polymyositis. These include: Muscular Dystrophy Association, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), Information Clearinghouse, National Institutes of Health, Myositis Association, and National Organization for Rare Disorders. Concerned patients or members of the public are always advised to consult with their doctors in addition to seeking medical information via public resources. Personal medical history is taken into account by a person’s private doctor, physician, or specialist.

For Further Information:

1 

“Polymyositis and Dermatomyositis.” ArthritisResearch UK, Arthritis Research UK, 2016. Web. 1 May 2016.

2 

“Polymyositis.” Cleveland Clinic, The Cleveland Clinic Foundation, 2015. Web. 1 May 2016.

3 

“Polymyositis.” The Johns Hopkins Myositis Center, Johns Hopkins Medicine, 2016. Web. 1 May 2016.

4 

“Polymyositis (PM).” MDA For Strength, Independence& Life, Muscular Dystrophy Association, Inc., 2016. Web. 1 May 2016.

5 

“NINDS Polymyositis Information Page.” National Institute of NeurologicalDisorders and Stroke, National Institute of Neurological Disorders and Stroke, 2015. Web. 1 May 2016.

6 

“Polymyositis-Adult.” The New York Times Health Guide, 22 March 2013. Web. 1 May 2016.

7 

“Polymyositis-Adult.” MedlinePlus, U.S. National Library of Medicine, 26 April 2016. Web. 1 May 2016.

8 

“Polymyositis.” Victoria State Government. Better Health Channel, State Government of Victoria, Australia, 2016. Web. 1 May 2016.

9 

MedicineNet. (2017) Polymyositis and Dermatomyositis Symptoms and Diagnosis. Retrieved on September 10, 2017 from medicinenet.com/polymyositis/article.htm

10 

Pappu, Ramesh,MD, DPH. MBBS: Chief Editor. (22 November 2016) Polymyositis Clinical Presentation. Retrieved on September 10, 2017 from emedicine.medscape.com/article/335925-clinical

Citation Types

Type
Format
MLA 9th
Jacob, Leah. "Polymyositis." Magill’s Medical Guide, 9th Edition, edited by Anubhav Agarwal,, Salem Press, 2022. Salem Online, online.salempress.com/articleDetails.do?articleName=MMG2022_1090.
APA 7th
Jacob, L. (2022). Polymyositis. In A. Agarwal, (Ed.), Magill’s Medical Guide, 9th Edition. Salem Press. online.salempress.com.
CMOS 17th
Jacob, Leah. "Polymyositis." Edited by Anubhav Agarwal,. Magill’s Medical Guide, 9th Edition. Hackensack: Salem Press, 2022. Accessed October 22, 2025. online.salempress.com.