Polymyositis and collagen disease • Weakness the dominant feature + evidence of an associated collagen disease 3. Severe collagen disease with minor weakness (polymyositis) • Dermatomyositis with florid skin changes and minor weakness 4. Polymyositis or dermatomyositis associated ABT-263 supplier with malignancy Walton and Adams also made some prescient pathological observations. In the more modern terminology of lumping versus splitting they noted “The basic uniformity of the histological change, in conformity with the nosology of the clinical

disease, leads us to conclude, for the moment, that all such cases should be considered as a single syndrome”. They noted the occasional absence of cellular infiltrates and whilst accepting that this might be due to inaccurate sampling also

suggested that it “might imply an aetiology other than allergy”. These Z-VAD-FMK datasheet cases may have represented what we now call necrotizing myopathy, and which may be either metabolic or immune-mediated in origin. Their cases with vacuolar change were almost certainly examples of sIBM. It was then nearly 20 years before the next major review of classification and the papers of Bohan and Peter [7], [8] and [9]. There is no doubting their importance and they have acted as a framework for diagnosis and epidemiological studies ever since. Arguably, over-strict adherence to them has to some extent stifled debate and it is appropriate to remember that in the first of their papers they stressed that their inhibitors criteria were “empirically derived” and that failure to meet the criteria did not necessarily exclude the diagnosis of PM and DM. Although it can hardly be called a failing, given knowledge available at the time, a “criticism” of their criteria is that they fail to recognise sIBM as a specific entity. Bohan and Peter recognised the need for accurate classification

Unoprostone and looked to develop diagnostic criteria akin to those used for rheumatic fever and rheumatoid arthritis. They proposed five major diagnostic criteria to define DM and PM (Box 2). I. Weakness • Symmetrical II. Muscle biopsy evidence of: • Necrosis of type 1 and 2 fibres III. Elevated muscle enzymes in serum IV. Electrophysiological triad • Small, short, polyphasic units V. Dermatological features • Heliotrope discolouration of eyelids + periorbital oedema The diagnosis of DM or PM could be considered Definite, Probable or Possible depending upon the number of criteria met, with cutaneous features being a sine qua non of DM ( Box 3). Definite ∘ DM: 3 or 4 major criteria (+ rash) With respect to overall classification of the IIM they proposed five groups, with each of which could be further defined as definite, probable or possible according to the above diagnostic criteria: • I: primary, idiopathic PM; Many would argue that the Bohan and Peter approach to classification and establishment of diagnostic criteria has served us well for many years, but it is clear that, as they said, their approach was empirical, based on observation.