Inflammatory myopathies are a group of rare autoimmune diseases that cause muscle weakness and inflammation. Unlike muscle pain from overuse or injury, inflammatory myopathy involves immune-mediated damage to muscle tissue and often affects other organ systems as well. Dr. Adam Elisha, DO, is a board-certified rheumatologist at St. Luke’s Rheumatology Associates in Duluth, MN with fellowship training in the diagnosis and management of inflammatory muscle diseases.
Types of Inflammatory Myopathy
- Polymyositis (PM): Characterized by progressive, symmetrical proximal muscle weakness (affecting the shoulders, hips, and thighs). Patients may have difficulty rising from a chair, climbing stairs, or raising their arms above their head.
- Dermatomyositis (DM): Similar to polymyositis but accompanied by characteristic skin findings — a purple-red heliotrope rash around the eyes, Gottron’s papules over the knuckles, and a V-sign or shawl sign rash on the chest and upper back. Dermatomyositis is associated with an increased risk of underlying malignancy, which warrants cancer screening at diagnosis.
- Immune-Mediated Necrotizing Myopathy (IMNM): Characterized by severe muscle weakness and very high muscle enzyme levels. Can be associated with statin use or specific autoantibodies (anti-SRP, anti-HMGCR).
- Antisynthetase Syndrome: A subtype characterized by myositis, interstitial lung disease (ILD), inflammatory arthritis, mechanic’s hands, fever, and Raynaud’s phenomenon. Associated with anti-Jo-1 and related antibodies.
- Inclusion Body Myositis (IBM): The most common inflammatory myopathy in adults over 50, causing slowly progressive weakness of the forearm flexors and knee extensors. Unlike other inflammatory myopathies, IBM does not respond well to immunosuppressive therapy.
Symptoms of Inflammatory Myopathy
- Progressive proximal muscle weakness (difficulty with stairs, rising from a chair, lifting overhead)
- Muscle pain or tenderness (though weakness is more prominent than pain in most forms)
- Fatigue and general feeling of illness
- Skin rashes (in dermatomyositis)
- Difficulty swallowing (dysphagia) in severe cases
- Shortness of breath (if the respiratory muscles or lungs are involved)
- Joint pain or arthritis
Diagnosing Inflammatory Myopathy
Evaluation includes muscle enzyme levels (CPK, aldolase, LDH), a myositis-specific antibody panel, MRI of affected muscle groups, electromyography (EMG), and often muscle biopsy for definitive diagnosis. Pulmonary function tests and chest CT are performed when lung involvement is suspected.
Treatment of Inflammatory Myopathy
Treatment is individualized based on the specific type of myopathy, severity, and organ involvement. High-dose corticosteroids are typically used first to suppress acute inflammation, followed by steroid-sparing agents such as methotrexate, azathioprine, mycophenolate mofetil, or IVIG (intravenous immunoglobulin). Rituximab is used for refractory disease. Physical therapy is critical for rebuilding and maintaining muscle strength throughout treatment.
Inflammatory Myopathy Care in Duluth, MN
If you or a loved one is experiencing progressive muscle weakness or other symptoms consistent with inflammatory myopathy, prompt evaluation by a rheumatologist is important. Dr. Adam Elisha at St. Luke’s Rheumatology Associates in Duluth provides expert diagnosis and individualized treatment. Call (218) 249-6960 to schedule an appointment.