In patients with a history of enthesitis-related JIA, which is similar to spondyloarthritis in adults, patients should be asked about a history of axial disease.
Dr. Sadun stated clearly that systemic JIA (sJIA) is essentially adult-onset Still’s disease, but with age of onset before 16 years. sJIA can be very aggressive, may have a number of systemic manifestations and may be poorly responsive to tumor necrosis factor-α (TNFα) inhibitor therapy. It is important to ask these patients about a history of lung involvement, macrophage activation syndrome (MAS), fevers and rash.
Finally, undifferentiated JIA is a wastebasket term for patients who either don’t meet criteria for another form of JIA or meet criteria for more than one form of JIA. In these patients, the adult rheumatologist should inquire about associated and extra-articular symptoms and treat on the basis of the type of adult inflammatory arthritis the patient has most closely exhibited to date.
A key point that Dr. Sadun discussed was that patients with JIA may uniquely have TMJ joint involvement. This can be an erosive, destructive process, with loss of joint space and development of micrognathia. On exam, it is important for pediatric and adult rheumatologists to auscultate the TMJ joints with their stethoscopes and listen for crepitus. If there is crepitus that worsens over time, this is worrisome for increasing disease activity in this joint. Patients should also be evaluated for maximum mouth opening capacity, which is defined as the maximal interincisal distance on unassisted active mouth opening. If this opening distance decreases over time, MRI with TMJ protocol may be needed to assess for disease activity and damage in this joint.
Differing Goals
Dr. Sadun noted a number of differences in management goals and medication uses between pediatric and adult rheumatologic care. She explained that the pursuit of remission can look quite different in adults than in children.
In a child, the risks associated with mild disease activity that persists for many decades may be greater than that seen in an older adult with fewer years to experience their disease. It is also important to recognize that children typically have much lower risks of infections than older adults. For both of these reasons, the goal in pediatric rheumatology is to achieve true disease remission, meaning absolutely no evidence of ongoing disease activity.
Because children tend to tolerate immunosuppression well overall and because of their more efficient drug metabolism, pediatric rheumatologists often feel more comfortable using higher doses of DMARDs and biologics than what is used in adult patients. For example, many patients with JIA may be started on methotrexate at a dose of 25 mg per week instead of working up to this dose.
