What is the treatment for polymyositis

How is the diagnosis of polymyositis and dermatomyositis made?

The diagnosis of PM / DM can often only be made after numerous, detailed examinations. If PM / DM-like symptoms are noticed by the patient or the attending GP, a specialist, i. H. in this case an internal rheumatologist should be consulted. He will then initiate the necessary examinations. A number of different examination methods are often required, the results of which are then assessed as a whole in order to be able to make the diagnosis of PM / DM. To this end, the rheumatologist cooperates with colleagues from a wide range of specialist disciplines (e.g. general medicine, dermatology, cardiology, pulmonology, neurology, etc.).

First, the rheumatologist will ask the patient about his general state of health (anamnesis). This includes inquiring about general and specific complaints, previous illnesses and the current medication. A subsequent physical examination, blood test and referral to representatives of the various specialist disciplines mentioned above can, among other things, provide information on possible organ involvement by PM / DM. The rheumatologist can then classify the PM / DM by looking at all the available findings, provided that the classification criteria are met. It should be mentioned here that classification criteria (which were developed for study purposes) should not be confused with diagnostic criteria.

Classification criteria

PM and DM are classified using the 2017 classification criteria developed by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). Certain, disease-specific complaints (symmetrical weakness of the muscles close to the trunk, difficulty swallowing) or findings are assigned different point values ​​and added up. Possible findings are: increased muscle values ​​in the blood (e.g. creatine kinase = CK, aldolase = ALD, aspartate amino transferase = AST, alanine amino transferase = ALT or lactate dehydrogenase = LDH); disease-specific antibody in the blood (anti-Jo1 antibody); pathologically altered muscles (demonstrated by a tissue sample). The same applies to the time (age of the patient) when the complaint began. The higher the score, the more likely the patient is to have PM. If there are also DM-typical skin changes (heliotropic rash, Gottron's papule or signs), DM can be classified. Pathological findings in magnetic resonance imaging (MRI) of the muscles with evidence of inflammatory changes as well as pathological changes in muscle activity, proven by electromyography (EMG), can also be helpful in classifying myositis.