Inflammatory myopathy

Inflammatory myopathy, also known as idiopathic inflammatory myopathy (IIM), is disease featuring muscle weakness, inflammation of muscles (myositis), and in some types, muscle pain. The cause of much inflammatory myopathy is unknown (idiopathic), and such cases are classified according to their symptoms and signs, electromyography, MRI, and laboratory findings. It can also be associated with underlying cancer. The main classes of idiopathic inflammatory myopathy are polymyositis (PM), dermatomyositis (DM) (including juvenile, amyopathic, and sine-dermatitis form), inclusion-body myositis (IBM), immune-mediated necrotising myopathy (IMNM), and focal autoimmune myositis.