A case of juvenile-onset ankylosing spondylitis effectively treated with tumour necrosis factor-alpha inhibitor agents.

A 15-year-old girl had experienced hip pain at 11 years of age. At 15 years of age, the patient complained of persistent generalised pain. Her rheumatoid factor and serum matrix metalloproteinase-3 levels were below standard values; there were no inflammatory responses, and the human leukocyte antigen test was negative for B27 and positive for B52 and B62. The bath ankylosing spondylitis disease activity index (BASDAI) value was 8.0 at the time of induction and 3.1 at 6 months after the introduction of adalimumab (at a dose of 40 mg). The BASDAI value improved with an increase in the dose of adalimumab to 80 mg at 8 months after the initial introduction of adalimumab (at 40 mg), although it remained at 4.8 at 16 months after the dose increase. The BASDAI value was 2.6 at 6 months, 2.7 at 1 year, and 1.8 at 1.5 years after the introduction of infliximab, indicating that the patient had progressed well without any adverse events. Based on this case, juvenile ankylosing spondylitis is a differential diagnosis for low back pain and generalised pain since childhood. Tumour necrosis factor (TNF) inhibitors were promptly introduced in this case, although it took 4 years from the initial presentation. TNF inhibitors were effective in treating juvenile ankylosing spondylitis in the present case without any adverse events. This case is notable because juvenile onset ankylosing spondylitis is one of the reasons for severe lumbago since childhood and because TNF inhibitors were administered promptly after diagnosis.