Atypical Presentation of Systemic Arthritis in a Toddler with Down Syndrome

Area of Science:

• Pediatric Rheumatology
• Immunology
• Genetics

Background:

• Systemic juvenile idiopathic arthritis (sJIA) is a chronic childhood inflammatory disease.
• Children with Down syndrome (DS) exhibit immune system abnormalities, leading to atypical disease presentations.
• DS patients face increased risks for sJIA-associated arthritis and interstitial lung disease (ILD), with high mortality.

Observation:

• A 21-month-old male with DS presented with an atypical sJIA case.
• Fever, a common sJIA symptom, was absent during the initial presentation.
• The patient later developed macrophage activation syndrome (MAS) and ILD.

Findings:

• This case demonstrates a rare, atypical sJIA presentation in a child with DS.
• The absence of initial fever underscores the variability of sJIA in this population.
• The development of MAS and ILD highlights severe potential complications.

Implications:

• Increased awareness of atypical rheumatic disease presentations in children with DS is crucial.
• Early recognition and management are vital for improving outcomes in these complex cases.
• This case contributes to understanding the spectrum of sJIA in immunocompromised pediatric populations.