Investigations for juvenile dermatomyositis

Blood investigations for juvenile dermatomyositis (JDM) includeGowdie, 2013:

• serum creatine kinase (CK) concentration—usually raised
• alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) concentrations—usually raised but may be normal
• autoantibodies—including myositis-specific antibodies and myositis-associated antibodies; awareness of antibodies in identifying disease subtypes is increasing.

Magnetic resonance imaging (MRI) of the proximal musculature has reduced the need for electromyography and muscle biopsy in children and adolescents with typical clinical features of JDM. MRI can demonstrate the pattern of muscle involvement and show oedema in affected muscles.

Investigations to exclude malignancy are not routinely required in children because unlike adult disease, JDM is not associated an increased risk of developing malignancy.