Juvenile dermatomyositis — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar in the clinic. A six-year-old girl has three weeks of progressive difficulty climbing stairs, a violaceous periorbital rash with oedema, and scaly red papules over her knuckles, and her creatine kinase is 2 400 U per litre. Talk me through your unifying diagnosis and your immediate plan. ^[1]

Exemplar opening (Candidate)

This child has a clinical picture strongly suggestive of juvenile dermatomyositis, the commonest idiopathic inflammatory myopathy of childhood, and I would move quickly because disease activity accumulates damage and the window to prevent calcinosis is open now. The combination of a heliotrope rash, Gottron papules and symmetric proximal weakness with a raised creatine kinase is characteristic. I will confirm muscle inflammation with aldolase and lactate dehydrogenase, image the thigh muscles with magnetic resonance imaging, send a myositis-specific antibody panel, and start treatment in parallel rather than waiting for every result. ^{[1] [2]}