Inside Pediatrics Spring 2015

Cron Leads Worldwide TMJ Arthritis

Inside the Medicine

The jaw opens and closes about 2,000 times a day. The motion is spontaneous and automatic, easy and fluid, both deliberate and involuntary. It’s also painless, or it should be. For children suffering from temporomandibular joint (TMJ) arthritis as a complication of juvenile idiopathic arthritis (JIA), though, the jaw can be a source of pain, and sometimes disfigurement, that most physicians struggle to treat. But pediatric rheumatologist Randy Cron, M.D., Ph.D, at Children’s of Alabama, is seeing some success in a uniquely aggressive approach to screening for and managing TMJ arthritis in his JIA patients. TMJ arthritis in children with chronic arthritis is difficult to diagnose. Too often, the first indication of disease is when evidence of deterioration and inflammation is clear. “We screen every child with JIA at the time of diagnosis by MRI with contrast because they’re asymptomatic until the damage is done,” Cron said. “The longer you wait, the harder it is to treat.” Those MRIs are performed in the Children’s imaging department, headed by Radiologist-in-Chief Yoginder Vaid, M.D. “Up to 80 percent of JIA patients have disease in the jaw at diagnosis,” Vaid said, “but it is clinically silent. We try to diagnose it early with MRI. It has become the gold standard.”

The scans are performed on an outpatient basis, although they may require anesthesia or IV sedation to keep the children, especially the youngest patients, still enough to get clear images. Some patients are scanned at Children’s main campus in downtown Birmingham, where the imaging department is equipped with both a 1.5 and a 3.0 TESLA MRI machine. Others are seen at the Children’s South outpatient center, about 20 miles away, where a 1.5 TESLA machine is in operation. Scans are repeated in children with JIA at least every six months if disease is present, Vaid said. “I think I can comfortably say our radiologists have read more TMJ MRIs since 2008 than anyone else on the planet,” Cron said. When signs of changes in the jaw are present on the images, Cron and his team have found that early and aggressive use of systemically administered arthritis medicines, such as tumor necrosis factor inhibitors, seem to partially help prevent such abnormal bone development as micrognathia (or small jaw), but are not completely effective in treating TMJ arthritis. “While almost all other arthritic joints in children with JIA respond very well to early and aggressive systemic therapy with tumor necrosis factor inhibitors like etanercept [Enbrel],

Dr. Randy Cron, rheumatology, said one in 1,000 children in the U.S. will develop chronic arthritis.

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