Myositis
| Myositis | |
|---|---|
idiopathic, adverse drug reaction |
Myositis is a rarely-encountered
Causes
Myositis can arise from various causes, including injury, certain medications, infections, inherited muscle disorders, or autoimmune conditions. In some instances, the origins of myositis remain idiopathic, without a discernible cause.
- Injury - A mild form of myositis can occur with hard exercise.[4] A more severe form of muscle injury, called rhabdomyolysis, is also associated with myositis.[4] This is a condition where an injury to the patient's muscles causes them to quickly break down.[4]
- Medicines - A variety of different medicines can cause myositis. One of the most common types of drugs that can cause myositis are statins, which are used to lower cholesterol levels. One of the most common side effects of statin therapy is muscle pain[5] which, more rarely, can lead to myositis.[5]
- Infection - The most common infectious cause of myositis is parasitic, and fungal infections.[6] Viruses, such as COVID-19, are also shown to be a rare cause of myositis.[7] Benign acute childhood myositishas been described in children after prodromal viral infections with different viral agents.
- Inherited muscle disease - Many inherited myopathies may have secondary myositis, including LMNA-associated myopathy.[8]
- Autoimmune - systemic lupus erythematosus, can also cause myositis-like symptoms.[4]
Diagnosis
There are various tools that can be used to help diagnose myositis. The most common methods are physical examination, electromyography (EMG), magnetic resonance imaging (MRI), muscle biopsy, and blood tests. The first course of action a doctor will likely take is perform a physical exam.[2] The doctor assesses for muscle weakness or rashes.
Another possible test is electromyography. This test involves the insertion of small needles into the patient's muscles.
Muscle biopsies, however, are the most reliable tests for diagnosing myositis.[4]
There are also a variety of blood tests available that help in the diagnosis of myositis. The doctor may look for an elevation of creatine kinase in the blood, which is indicative of muscle inflammation.[4] Certain autoantibodies (antibodies that target muscle cells) can also be found in the blood, which can indicate that myositis is caused by an autoimmune disease.[3] Some specific examples of autoantibodies are Anti-Jo-1, Anti-HMGCR, Anti-TIF1, etc.[3]
Treatment
Treatment for myositis depends on the underlying cause.[4] For myositis, which is caused by a viral infection, no treatment is typically needed.[4] For myositis caused by a bacterial infection, antibiotics can be used.[4] For myositis caused by a medication, it is important to stop using that medication.[4]
There are a variety of treatment options available if myositis is caused by an autoimmune disease.
See also
- Benign acute childhood myositis
- Inflammatory myopathies
- Myopathy (muscle disease)
- Myalgia (muscle pain)
- Masticatory muscle myositis (a disease in dogs)
- Perimyositis
- Sarcoidosis § Bones, joints, and muscles
References
- ^ "Amplified Musculoskeletal Pain Syndrome (AMPS)". Children's Health.
- ^ PMID 23981102.
- ^ S2CID 41157692.
- ^ a b c d e f g h i j k l m n o Hoffman M (19 April 2021). DerSarkissian C (ed.). "Myositis: Symptoms and Causes". WebMD. Retrieved 2022-06-12.
- ^ S2CID 3239804.
- PMID 30505013.
- PMID 34216297.
- S2CID 25515951.
- S2CID 25027014.
- ^ S2CID 4934267.
- PMID 25406359.
External links
- Myositis: NIH
Myositis Association https://www.myositis.org