Inflammatory Myositis Diagnosis refers to a group of diseases characterized by muscle weakness and inflammation. The muscle inflammation is caused by the body’s immune system attacking and damaging healthy muscle tissues for an unknown reason. Some of the most common types of inflammatory myositis include dermatomyositis, polymyositis, and inclusion body myositis.
Symptoms of Inflammatory Myositis
The main symptoms of inflammatory myositis include progressive weakness and pain in the proximal (close to the trunk) muscle groups of the limbs and neck. Some other common symptoms are difficulty climbing stairs, rising from a chair, or lifting objects overhead. Fatigue is another hallmark symptom that is usually out of proportion to physical activity levels. Additional symptoms may include low-grade fever, skin rashes, photosensitivity, and nailfold changes in dermatomyositis cases. It is important to see a doctor if any persistent muscle weakness or pain is experienced.
Blood Tests in Diagnosis
The initial evaluation of a potential myositis case begins with blood tests. Elevated muscle enzyme levels such as creatine kinase (CK), lactate dehydrogenase (LDH), and aldolase are suggestive of muscle damage and inflammation. Additional routine blood tests like a complete blood count, electrolytes, and liver/kidney function tests may help rule out other disease processes. Autoantibody tests are also done to check for autoimmune disorders and help distinguish between the different types of inflammatory myositis. Specific autoantibodies associated with myositis include anti-Jo-1, anti-Mi-2, anti-SRP, and anti-HMGCR.
Electromyography (EMG) is usually the next diagnostic test performed. EMG evaluates nerve and muscle function through small needle electrodes inserted into specific muscles. Abnormalities detected on EMG support an inflammatory myopathy diagnosis. A muscle biopsy, where a small sample of muscle is removed for examination under a microscope, provides the most definitive evidence of myositis. Features such as muscle inflammation, necrosis, and invasion by mononuclear inflammatory cells help confirm the diagnosis. The findings on the biopsy are also crucial for distinguishing between the main types of inflammatory myositis.
Imaging Tests
Imaging tests like magnetic resonance imaging (MRI) can help assess the extent and distribution of muscle involvement in myositis cases. MRI is usually more sensitive than regular X-rays at detecting subtle muscle abnormalities. While not required for Inflammatory Myositis Diagnosis, imaging is useful for monitoring disease progression and response to treatment over time. Ultrasound is another modality sometimes used to visualize muscle structure and texture changes in myositis patients.
Final Diagnosis and Treatment
Making a definitive Inflammatory Myositis Diagnosis involves considering all available clinical and diagnostic evidence. Criteria developed by organizations like Bohan and Peter help classify patients as having definite or probable myositis with standardized evaluation protocols. Once diagnosed, treatment usually involves immunosuppressive medications like corticosteroids, methotrexate, or azathioprine aimed at reducing muscle inflammation and damage. Additional symptom management and physical/occupational therapy also play a vital role. Prognosis depends on how quickly treatment is initiated and individual patient factors, but the overall long-term outlook is improving with newer targeted therapies. Regular monitoring with repeat exams and tests is important for disease assessment and management over the long term as well.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it