Myositis is a condition that refers to the inflammation of the muscles. It is considered a form of autoimmune disorder. However, myositis may be caused by injury, infection, or drug toxicity. Typically, patients with myositis may feel fatigued and tired after walking or standing for a long time. They may also have swelling, pain and discomfort, trouble with swallowing, or breathing.
There are several types of myositis, depending on the severity and location of the affected muscle. Some of the different types of myositis include dermatomyositis, polymyositis, toxic, and juvenile myositis. Diagnosis of myositis is usually made by performing a series of tests such as physical examination, MRI scans, biopsy, nerve conduction study, and blood tests to rule out possible conditions and identify the exact cause of this condition.
Treatment of myositis mainly consists of a combination therapy of medications and physical exercises to treat the symptoms. Simultaneously, in the case of autoimmune disorder, palliative therapy may be continued to treat the underlying cause. Today’s article will highlight the types of myositis. Furthermore, we will discuss the diagnosis and treatment of myositis.
What is myositis?
Myositis typically means inflammation of the muscles in the body. It is a chronic, progressive disorder that is commonly associated with skin rashes. Primarily myositis causes pain and soreness of the muscle. Additionally, it may lead to muscle fatigue, difficulty in breathing, and swallowing. (1)
The prevalence of myositis is estimated to be around 1600 to 3200 new cases each year. Myositis can affect both children and adults. Therefore, it is considered as a dangerous disorder.
What causes myositis?
As mentioned above, myositis is an autoimmune condition that mainly causes the body to attack its muscles. Therefore, in most of the cases, the definite cause is unknown. However, some experts think that it may be triggered by an injury or infection of the muscle. Some researchers also believe that myositis may be associated with the following conditions –
- Rheumatoid arthritis
- Lupus
- Common cold, flu or even HIV
- Drug toxicity
What are the types of myositis?
Typically, there are five types of myositis depending on the severity and location of the symptoms –
Dermatomyositis
It is the most common form of myositis that is characterized by purple to red rashes shaped in the form of a heliotrope flower on the skin. Often, this type of myositis affects the eyelids, face, chest, neck, and back. Moreover, it may spread to elbows, knees, and toes. (2) Symptoms of dermatomyositis include –
- Muscle weakness especially in the neck, back, hip and shoulders
- Dry, scaly skin
- Gottron’s papules – small raised and rough bumps over the knuckles, elbow, knees, and toes
- Hoarseness of the voice
- Difficulty in swallowing
- Muscle pain and joint inflammation
- Weight loss
- Irregular heartbeat
- Gastric ulcers
Inclusion – body myositis
This type of myositis affects men more than women above the age of 50 years. The weakness of muscles in this condition begins from the wrist, fingers, and thigh muscles. some of the symptoms f inclusion-body myositis include –
- Loss of balance
- Trouble rising from a seated position
- Weak handgrip (3)
- Difficulty in walking
- Muscle pain and weakness
- Diminished deep tendon reflexes
Juvenile myositis
As the name suggests, this type of myositis mainly affects children under the age of 18 years. Girls are more likely to get affected by juvenile myositis. Some of the characteristic features of juvenile myositis are as follows –
- A red-purplele rash over the eyelids and joints in the shape of a heliotrope flower
- Muscle weakness and pain
- Stomach aches
- Irritability
- Trouble in climbing stairs, rising from a seated position and getting dressed
- Hard lumps of calcium under the skin
- Joint pain
- Gottron’s papules
- Hoarseness of voice
Polymyositis
Polymyositis mainly affects the muscles of the trunk and expands gradually. It is commonly found in people with autoimmune diseases. Some of the typical features of polymyositis are as follows –
- Muscle pain and weakness
- Chronic dry cough
- Thickening of the skin on the hands (4)
- Difficulty breathing and swallowing
- Feeling of falling
- Trouble rising from a seated position
Toxic myositis
Medications and illicit drugs usually cause toxic myositis. Commonly, cholesterol-lowering medications such as statins lead to toxic myositis. Some other drugs responsible for this condition include –
- Immunosuppressant
- Omeprazole
- Cocaine
- Toluene – paint thinner that is used as an illicit drug
How is myositis diagnosed?
Typically, the diagnosis of myositis includes a detailed physical examination and blood test. Some other investigations may consist of –
- Electromyography
- MRI scan
- Nerve conduction study
- Antinuclear antibody blood test (5)
- Myositis specific antibody panel blood test
- Muscle biopsy
- Genetic testing
What is the treatment for myositis?
Treatment of myositis varies depending on the underlying cause. However, medications like prednisone, immunosuppressant drugs, and methotrexate may be prescribed. Additionally, physical exercises such as stretching and yoga may help to keep the muscle healthy and flexible. Moreover, it helps to prevent muscle atrophy. (6)
Take away message
Myositis is a chronic condition that causes inflammation of the muscles in the body. Typically, it is classified into five types depending on the severity of the disease. Myositis affects both children and adults and leads to muscle pain and weakness.
Often, the common symptoms of any type of myositis include muscle fatigue, difficulty in walking, or rising from sitting position, difficulty in breathing and swallowing. Additionally, skin rashes, loss of balance, and hoarseness of voice may also be experienced by some patients.
Although there is no exact cause of myositis, it may be associated with autoimmune diseases such as arthritis and lupus, injury, and infections. Diagnosis includes a series of physical, blood tests, and soft tissue scans. Treatment includes a course of medication and physical therapy to cure the symptoms and treat the underlying cause.