investigation At this time, MSAs are of greatest utility in cases with atypical features, for example in those without the characteristic rash or with features of an overlap syndrome FIGURE 101.5 Gottron papules in juvenile dermatomyositis (JDM) (Courtesy of Lisa Rider, MD.) Because JDM is a microangiopathic process, active disease is also characterized by elevated levels of von Willebrand factor antigen (vWF:Ag), which is released by damaged endothelial cells In contrast, evidence of systemic inflammation may be absent, and acute-phase markers (including ESR and CRP) and CBCs are typically normal MRI of the bilateral thighs may be the most sensitive method of documenting muscle inflammation ( Fig 101.4 ) Muscle biopsy can elucidate the diagnosis; however, the diagnosis is more often made without it Evidence of cardiac involvement should also be sought, particularly with an EKG and an echocardiogram Serologic markers of myocardial involvement are unreliable because both the CK-MB fraction and the troponin level are elevated in JDM due to myoblast proliferation in skeletal muscles Management General Management The primary goal of therapy is to aggressively control muscle inflammation The more rapidly markers of myocyte damage such as CK and aldolase can be normalized, the lower the chance that acute and chronic complications will occur Thus, virtually all children with clinical or biochemical evidence of muscle inflammation begin treatment with pulsed doses of IV methylprednisolone (30 mg/kg, maximum 1.5 g) infused over to hours Oral prednisone is then started at a dose of to mg/kg/day If muscle