Inflammatory Myopathy

1. Inflammatory Myopathy
AdeWijaya, MD – April 2021

2. Polymyositis
Inclusion Body
Myositis
Dermatomyositis

3. Polymyositis
• Proximal weakness
• Elevated CK enzyme
• 1:100.000
• F:M – 2:1
• Onset 40-50 tahun
• Marked atrophy
• Muscle pain sometimes

4. Dermatomyositis
• Similar features to polimyositis + skin lesions

5. Inclusion Body Myositis
• Older onset; > 50 years old
• Chronic/slow progression
• Proximal and distal muscles
• Marked atrophy
• Painless

6. Pathophysiology
• Autoimmune
• T-cells and macrophage mediated
• Cytokines: gamma-interferon and interleukins  damage
myofibres

7. Evaluation
• History and physical examination
• CK enzyme
• Electromyography
• MRI
• Muscle biopsy

8. Treatment
• Corticosteroids
• Immunosuppressants: azathioprine, mycophenolate mofetil,
methotrexate, tacrolimus, cyclosporine, rituximab, and
cyclophosphamide.
• Consider intravenous immunoglobulin in severe and refractory
cases

9. Prognosis
• Good with partial or complete recovery
• Unless in severe respiratory muscles involvement 
potentially fatal.

10. THANKYOU

11. References:
• Sasaki H, Kohsaka H. Current diagnosis and treatment of polymyositis and dermatomyositis.
Modern rheumatology. 2018 Nov 2;28(6):913-21.
• Sriram S,Varghese CM. Case study on polymyositis. MOJ Biol Med. 2017;1(1):15–16.
DOI: 10.15406/mojbm.2017.01.00004
• Guimarães JB, Nico MA, OmondAG, Aivazoglou LU, Jorge RB, Zanoteli E, Fernandes AR.
Diagnostic imaging of inflammatory myopathies: new concepts and a radiological approach.
Current rheumatology reports. 2019 Mar;21(3):1-3.
• Grundtman C, MalmströmV, Lundberg IE. Immune mechanisms in the pathogenesis of idiopathic
inflammatory myopathies. Arthritis ResTher 2007;9:208.
• Moghadam-Kia S, Aggarwal R, Oddis CV.Treatment of inflammatory myopathy: emerging
therapies and therapeutic targets. Expert Rev Clin Immunol 2015;11:1265–75.
• Venalis P, Lundberg IE. Immune mechanisms in polymyositis and dermatomyositis and potential
targets for therapy. Rheumatology 2014;53:397–405.