Inflammatory myopathy is disease featuring weakness and inflammation of muscles and (in some types) muscle pain. The cause of much inflammatory myopathy is unknown (
idiopathic
An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. From Greek ἴδιος ''idios'' "one's own" and πάθος ''pathos'' "suffering", ''idiopathy'' means approximately "a disease of its own kind ...
), and such cases are classified according to their
symptom
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
s and
signs
Signs may refer to:
* ''Signs'' (2002 film), a 2002 film by M. Night Shyamalan
* ''Signs'' (TV series) (Polish: ''Znaki'') is a 2018 Polish-language television series
* ''Signs'' (journal), a journal of women's studies
*Signs (band), an American ...
and
electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyo ...
,
MRI and laboratory findings. It can also be associated with underlying cancer. The main classes of idiopathic inflammatory myopathy are
polymyositis
Polymyositis (PM) is a type of chronic inflammation of the muscles ( inflammatory myopathy) related to dermatomyositis and inclusion body myositis. Its name means "inflammation of many muscles" (''poly-'' + '' myos-'' + ''-itis''). The inflammat ...
(PM),
dermatomyositis
Dermatomyositis (DM) is a long-term inflammatory disorder which affects skin and the muscles. Its symptoms are generally a skin rash and worsening muscle weakness over time. These may occur suddenly or develop over months. Other symptoms may in ...
(DM), and
inclusion-body myositis (IBM).
Diagnosis
There are a number of know