SANTA MONICA, CALIF. — There is only one cause of joint inflammation in childhood that the child will typically outgrow: true oligoarthritis. Even though the inflammation will eventually pass, affected children still need treatment to prevent limb-length discrepancy or blindness resulting from uveitis, according to Dr. Thomas J.A. Lehman.
Because of the shortage of pediatric rheumatologists, adult rheumatologists often end up treating children with new-onset joint symptoms, he noted at the meeting sponsored by
Without genetic markers, it is difficult to separate all the types of arthritis—which are not limited to just the eight subtypes listed in the official diagnostic criteria—that occur in children. “There may be anywhere from 30 to 50 subtypes” of arthritis in children. This matters, because they will not all respond to the same treatment or have the same disease course, said Dr. Lehman, chief of the division of pediatric rheumatology at the Hospital for Special Surgery in New York.
Oligoarthritis is not a systemic disease, which makes it harder to diagnose early. The onset of joint swelling and pain should be limited to four or fewer large joints during the first 6 months, and most often only a single joint is affected. Because the stiffness and pain are worse upon awakening and tend to ease as the day progresses, parents often let it continue awhile and often cannot pinpoint when the symptoms started. Also, onset usually occurs at age 1–5 years (and typical oligoarthritis never begins after age 9 years), which means that the children are too young to describe their symptoms. A limp in the morning and a swollen knee may be the only sign that something is wrong; sometimes a visiting grandmother notices what the parents have overlooked.
Laboratory findings—or lack thereof—can help confirm the diagnosis. Because this is not a systemic disease, the hemoglobin level is never less than 11.0 g/dL and the erythrocyte sedimentation rate is never greater than 40 mm/h, according to Dr. Lehman. There is never fever, rash, or elevated white blood cell count. Oligoarthritis affects more girls than boys. The children are often positive for antinuclear antibodies and often have eye disease, usually uveitis.
It is important to make the diagnosis of true oligoarthritis as early as possible, according to Dr. Lehman. Too many children are allowed to continue limping without a diagnosis because some criteria require joint pain for at least 6 weeks, and others say 3 months. That doesn't mean children can't be treated before a definitive diagnosis of oligoarthritis is made, he said. Continued pain produces muscle loss and joint damage. In addition, it hinders a child's emotional development when they can's keep up with their friends and participate in normal activities.
Many children with true oligoarthritis will respond to NSAIDs, but physicians should use all the medication necessary to control the disease, he noted. Corticosteroid injections may be helpful if there is a single “stubborn” joint.
This arthritis never involves the fingers or hips and never more than four joints. “True oligoarthritis affects only the knees,” said Dr. Lehman, who stressed that these diagnostic criteria are his own and are not accepted by any accrediting body.
Children who present after age 9 years or who have involvement of four or fewer joints that expand to more than four joints do not have true oligoarthritis. Theirs is likely to be a debilitating arthritis, and they will not outgrow it, he stressed.
Disclosures: Dr. Lehman has financial relationships with Celgene Corp., BioMarin Pharmaceutical Inc., Genentech Inc., Bristol-Myers Squibb Co., Abbott Laboratories, Wyeth (now owned by Pfizer Inc.), and Amgen Inc. SDEF and
To see an interview with Dr. Lehman, please go to www.youtube.com/rheumatologynews