Juvenile spondyloarthropathy: an important clinical lesson to remember.

Spondyloarthropathy (SpA) is a group of inflammatory conditions that include spondylitis, sacroiliitis, asymmetrical peripheral arthritis and enthesitis. This condition is known as juvenile SpA when the diagnosis is made in patients up to 16 years of age. Enthesitis is a highly specific feature that occurs more often in juvenile SpA than in the adult form. In contrast to adult onset SpA, the initial manifestation of juvenile SpA rarely presents as inflammatory back pain. Peripheral arthritis is the more common presenting feature. We report a case of a 12-year-old boy who presented with a 1-year history of progressive low back pain, gluteal pain and thigh pain. There were no clinical symptoms of arthropathy of the distal extremities. MRI of the whole spine was performed twice, which, unfortunately, was unyielding. Finally, MRI of the sacroiliac joints revealed asymmetric sacroiliitis as well as enthesitis of the hips and pelvis. Further laboratory data showed negative rheumatoid factor and positive human leucocyte antigen (HLA) B27. A diagnosis of juvenile SpA with sacroiliitis and enthesitis was made. The imaging characteristics of juvenile SpA are highlighted.