Juvenile dermatomyositis: a case of delayed recognition with unusual complication of nephrocalcinosis

Area of Science:

• Pediatric Rheumatology
• Dermatology
• Nephrology

Background:

• Juvenile dermatomyositis (JDM) is the most common childhood inflammatory myopathy, primarily affecting skin and muscles.
• Renal involvement is uncommon in JDM, unlike other autoimmune diseases such as lupus.
• Calcinosis cutis, the deposition of calcium in the skin, can be a complication of JDM.

Observation:

• A child presented with extensive calcinosis cutis as the primary complaint.
• Subtle proximal muscle weakness was noted on physical examination.
• Diagnostic workup, including MRI and muscle biopsy, confirmed underlying myositis.

Findings:

• Routine ultrasound screening revealed bilateral medullary nephrocalcinosis.
• This case represents the first reported instance of JDM associated with both calcinosis cutis and bilateral medullary nephrocalcinosis.
• The co-occurrence of these conditions in a pediatric patient is highly unusual.

Implications:

• This case expands the understanding of potential JDM manifestations beyond skin and muscle involvement.
• It underscores the importance of thorough systemic evaluation in children diagnosed with JDM, even with atypical presentations.
• Early detection and management of renal complications like nephrocalcinosis are crucial for improving patient outcomes in JDM.