Polymyositis is a connective tissue disease that triggers inflammation and muscular weakness. The cause is unknown, but polymyositis is thought to be an tissue. The disease is more common in women than men and tends to develop between the ages of 50 to 70 years, although anyone of any age or either sex can be affected.
Usually, the muscle weakness develops gradually over the course of a few weeks or months. The inflammation may spread to other areas of the body including the. In many cases, polymyositis is associated with other autoimmune disorders of connective tissue such as The symptoms include: Tendency to fall over.
Polymyositis develops gradually over weeks or months
By the time the person experiences symptoms, they have already lost around half of their muscle fibres to the disease. The head, hands and feet are usually untouched by the disease. Difficulties may include:
- Profound muscular weakness in affected body parts
- such as being unable to lift the arms above shoulder height or lift the head off a pillow In its later stages
- abnormal shortening of muscles (contracture)
The cause of polymyositis hasn’t been found, but there is good evidence to indicate that it is likely to be an autoimmune disorder, which means the immune cells mistakenly attack the muscle fibres of the body.
If a small tag ( ) of affected muscle is examined in a laboratory, it looks withered and studded with immune system cells.
Muscle tissue could be damaged by the immune system as it tries to rid the tissue of a viral infection.
As people with polymyositis are likely to have other connective tissue disorders, such as rheumatoid arthritis or scleroderma, there could be a genetic susceptibility. People with polymyositis also tend to have family members with connective tissue disorders, which further supports the theory of an inherited tendency.
The person may experience difficulties with breathing or swallowing if the associated muscles weaken too severely.
Some of the other possible complications of polymyositis include:
- Respiratory failure. Polymyositis is sometimes mistaken for muscular dystrophy
- so careful diagnosis is important. Some of the tests for polymyositis include
- people with other connective tissue diseases
- such as scleroderma
- are at greater risk of polymyositis
This is the definitive test for polymyositis
– these include magnetic resonance imaging. – an antibody titre is included, since polymyositis is characterised by the overproduction of particular antibodies. There are also higher than normal amounts of a muscle enzyme indicating muscle damage (creatine phosphokinase) circulating in the bloodstream, which can be measured by a specific blood test.
The outlook for polymyositis is hard to predict
Some people will recover, most will respond satisfactorily to treatment, while others will die from complications. Treatment options include:
- used to dampen the activity of the immune system reduce inflammation. For some people corticosteroids contribute to muscle weakness
- so other medications have to be used instead
Only the blood cells are returned to the patient, leaving the antibodies behind in the plasma. – a special protein obtained from the plasma of blood donors, and administered intravenously, has sometimes had good results in difficult cases. – helps strengthen muscles.
– includes blood tests, so that medications can be adjusted if necessary. Generally, the initial doses are high, then gradually tapered down. Dermatomyositis is not the same disease, but is often grouped with polymyositis.
They share many similarities such as muscle inflammation and weakness, immune system involvement and similar treatment therapies. Apart from muscular weakness, other symptoms of dermatomyositis include:
- Children aged between five years most commonly affected. autoimmune disorder possibly triggered by a viral infection of muscle heart Since symptoms differ between individuals
- polymyositis is hard to diagnose
- may be mistaken for muscular dystrophy scleroderma
- systemic lupus erythematosus
- rheumatoid arthritis
- Sjogren’s syndrome Symptoms of polymyositis The shoulders
- hips usually affected first Muscular weakness Muscle wastage Muscle pain Fatigue Breathlessness Swallowing difficulties Tremors
- particularly of the hands Wide-footed stance
- walking style Clumsiness Progression of weakness Voice changes
- if the muscles of the larynx are affected Problems with swallowing if the oesophagus is affected
- with a tendency to regurgitate food Peristalsis (the muscular contractions of the bowel ) may falter
- dark red skin rash on the cheeks
- shoulders chest Sometimes the whole skin surface may appear reddened Swollen
Key Points
- cause is unknown, but polymyositis is thought to be an tissue
- By the time the person experiences symptoms, they have already lost around half of their muscle fibres to the disease
- Polymyositis is sometimes mistaken for muscular dystrophy, so careful diagnosis is important
- – these are used to exclude other causes such as bacterial or parasitical infections of muscle tissue
- Some people will recover, most will respond satisfactorily to treatment, while others will die from complications