The spondyloarthropathies (SpAs) are a heterogeneous group of seronegative inflammatory arthropathies affecting peripheral and axial joints, and entheses and demonstrate strong association with human leukocyte antigen (HLA) B27. The term “spondyloarthritis” isn’t favoured by paediatric rheumatologists due to its absence in the International League of Associations for Rheumatology (ILAR) criteria for Juvenile Idiopathic Arthritis (JIA) where in distinct classifications of Enthesitis Related arthritis (ERA) and psoriatic arthritis (PsA) are employed. Despite shared characteristics, recognizing disparities in nomenclature, classification criteria, presentation, and treatment is pivotal, especially when transitioning from paediatric to adult care.

Navigating Nomenclature and Criteria

Adult SpAs encompass axial SpA, including ankylosing spondylitis (AS) and non-radiographic axSpA, along with other forms like psoriatic arthritis, enteropathic arthritis, reactive arthritis, and undifferentiated SpA. In contrast, JIA includes ERA and PsA separately and does not specifically account for IBD–associated arthritis, juvenile ankylosing spondylitis, or reactive arthritis. In comparison to the Adult Assessment of Spondylarthritis International Society (ASAS) criteria, paediatric criteria do not address axial disease, and there is no inclusion of imaging, markers of inflammation, or therapeutic response criteria. Peadiatric criteria, on the other hand, are inclusive of any tender enthesis as part of the JIA criteria, whereas the adult criteria limit the inclusion of enthesitis to enthesitis of the heel. Discrepancies also exist in criteria for psoriatic arthritis, with paediatric criteria limiting family history to a first-degree relative and omitting image for new bone formation.

Unraveling Clinical Presentations

The onset of SpA spans across childhood to adolescence and adulthood with a peak incidence in late adolescence and early adulthood. Key differences emerge in the clinical presentation: juvenile SpA (JSpA) exhibits predominant peripheral arthritis and enthesitis, contrasting with an adult-onset disease where axial manifestations are more common. Children with ERA experience insidious onset, asymmetrical oligoarthritis, and rare axial involvement at the disease’s start. Uveitis in JSpA appears distinct, characterized by red, painful, and recurrent episodes. JSpA also displays lower HLA-B27 positivity, decreased acute anterior uveitis, increased peripheral arthritis, and enthesitis, with reduced axial involvement compared to adult-onset cases. Gastrointestinal symptoms are prevalent in JSpA, mirroring adult patterns, while cardiac complications are rare in paediatric cases.

Tailoring Treatments Across Age Divides

NSAIDs, specifically naproxen, remain the primary choice for symptomatic relief in peripheral and axial symptoms of ERA. In cases of limited joint disease, additional intraarticular glucocorticoids are employed, with short courses used as ‘rescue therapy’ for severely ill patients or in the presence of widespread, severe joint inflammation. Unlike adults, Methotrexate is the preferred first-line DMARD for peripheral arthritis in children. Sulfasalazine, though considered ineffective for axial disease, also proves beneficial for managing peripheral disease activity. As the impact of DMARDs on axial disease is still unclear, early consideration of biological therapies is advocated. We prefer TNF inhibitors, such as adalimumab or etanercept, for refractory arthritis and enthesitis, especially when peripheral or axial disease is unresponsive to DMARDs.

Transitioning Challenges in Care

Transitioning paediatric patients to adult care is a critical process and requires collaboration between paediatric and adult healthcare providers. Careful planning, communication, and education empower patients and families to navigate the adult healthcare system effectively. At our centre, anticipating the transition, we facilitate introductions between patients and their future physicians during periods of relative stability, avoiding referrals during acute illness. A detailed summary of the patient’s course and management is immensely helpful for the new team and provides reassurance to the patient and family.
 

Suggested Reading

1. Fisher C, Ciurtin C, Leandro M, Sen D, Wedderburn LR. Similarities and Differences Between Juvenile and Adult Spondyloarthropathies. Front Med (Lausanne).2021; 8:681621.
2. Weiss PF, Roth J. Juvenile-Versus Adult-Onset Spondyloarthritis: Similar, but Different. Rheum Dis Clin North Am.2020;46(2):241-257.