Juvenile onset spondyloarthropathies: therapeutic aspects

Abstract

Juvenile onset spondyloarthropathy (SpA) is a term that refers to a group of human leucocyte antigen (HLA)-B27 associated inflammatory disorders affecting children under the age of 16 years, producing a continuum of clinical symptoms through adulthood. This disease is characterised by enthesopathy and arthropathy affecting the joints of the lower extremities and seronegativity for IgM rheumatoid factor and antinuclear antibodies. Children usually present with undifferentiated SpA and progress to differentiated forms over time. Except for the prevalence of some clinical features at onset, the pathogenic and clinical aspects of juvenile onset SpAs resemble those of the adult disease. Thus application of the same or similar therapeutic measures for both juvenile and adult onset SpAs seems logical. Current treatments for juvenile onset SpA provide symptomatic improvement, but do not alter disease progression. The increased expression of tumour necrosis factor alpha (TNFalpha) in synovial tissue of patients with adult and juvenile onset SpA and its correlation with infiltration of inflammatory mediators into the synovia suggest a significant pathogenic role of this cytokine. Clinical trials of anti-TNFalpha antibody (infliximab) therapy in patients with adult onset SpA have demonstrated significant clinical improvement in inflammatory pain, function, disease activity, and quality of life in correlation with histological and immunohistochemical evidence of modulation of synovial inflammatory processes. These promising findings suggest that anti-TNFalpha therapy may confer similar benefits in patients with juvenile onset SpA.

Figure 1

Progression of children with juvenile onset undifferentiated spondyloarthropathy to fulfilment of the modified New York diagnostic criteria for AS over a 10 year period. The percentages of patients fulfilling each criterion are shown for each time. Most patients fulfil diagnostic criteria for definite AS after a mean of 7.5 years (range 5–10) after the onset of symptoms of juvenile onset SpA. Reproduced with permission of the authors and Rheumatic Disease Clinics of North America from Burgos-Vargas R et al. Rheum Dis Clin North Am 1997;23:569–98. Copyright © 1997 W B Saunders Company.

Figure 2

Cumulative frequency of joint disease in juvenile onset ankylosing spondylitis 10 years after diagnosis. Reproduced with permission of the authors and Rheumatic Disease Clinics of North America from Burgos-Vargas R et al. Rheum Dis Clin North Am 1997;23:569–98. Copyright © 1997 W B Saunders Company.

Figure 3

Long term structural changes of the feet in a 20 year old patient with juvenile onset AS. (A) Dorsoplantar aspect showing metatarsophalangeal joint surface erosions and misalignment. (B) Left foot oblique view showing ankylosis of the first metatarsal and cuneal bones, metatarsophalangeal joint subluxations and enthesophytes at the margin of the 5th metatarsal-cuneal joint. (C, D) Right and left lateral views showing a spectrum of changes, including enthesophytosis at the plantar fascia attachment to the calcaneus and complete fusion of the tarsal bones (ankylosing tarsitis in C and enthesophytosis of the talonavicular joint in D). These previously unpublished figures are provided courtesy of Dr R Burgos-Vargas.