Juvenile dermatomyositis with IgA nephropathy: case-based review

Area of Science:

• Pediatric Rheumatology
• Pediatric Nephrology
• Immunology

Background:

• Juvenile dermatomyositis (JDM) is the most common idiopathic inflammatory myopathy in children, typically presenting with characteristic skin rashes and proximal muscle weakness.
• Renal involvement, such as acute kidney injury and glomerulonephritis, is an uncommon complication of JDM.

Observation:

• This report details a 10-year-old boy diagnosed with JDM and IgA nephropathy.
• The patient exhibited a significant response to standard JDM treatments, including steroids and methotrexate.
• No specific renal treatment was required, and the child achieved remission with normal kidney function and urinalysis at follow-up.

Findings:

• Literature review identified 11 cases of renal involvement in idiopathic inflammatory myopathies (IIMs).
• Among these, four patients had IgA nephropathy (one JDM, three other IIMs).
• Three of the four IgA nephropathy patients improved with primary disease treatment alone.

Implications:

• Treatment of the underlying JDM is often sufficient for managing secondary IgA nephropathy in pediatric patients.
• This suggests a potential link between inflammatory myopathies and IgA nephropathy, warranting further investigation.
• Early diagnosis and management of JDM may prevent or mitigate renal complications.