A new study suggests that serious lung complications may be more common in patients with systemic juvenile idiopathic arthritis (sJIA) than previously believed. These complications can go undiagnosed and may be fatal. But researchers stress that they affect a very small subset of patients and, if identified early, can be addressed.

The complications include three conditions in which inflammation is suspected of playing an important role: pulmonary artery hypertension (PAH), interstitial lung disease (ILD) and alveolar proteinosis (AP). Until 2008, there were only scattered reports of these diseases in sJIA, but more frequent reports have surfaced since then. This led researchers to question whether there is link between these lung problems and the use of certain biologics – such as anakinra (Kineret) and canakinumab (Ilaris) – which became more common around the same time.

The study, which was published online recently in Arthritis Care & Research, compared a group of 25 children with one or more of these lung complications to 389 sJIA patients without lung complications to see if they differed in important ways. The children in the second group came from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry database.

“We are looking at reports from physicians about these complications in these children. And the concern is [they] tend to be increasing in the past five to 10 years,” says study author Yukiko Kimura, MD, chief of pediatric rheumatology at the Joseph M. Sanzari Children’s Hospital at Hackensack University Medical Center in New Jersey. “It is something that we need to pay more attention to and be more concerned about.”

But Dr. Kimura also cautions that the incidence of these complications remains quite rare. She says that up to 10 percent of juvenile idiopathic arthritis patients have systemic JIA, which is very different from other types of JIA and is associated with a daily fever, rash and problems outside of the joints, including in different organs.

The comparison shows the patients who developed the three pulmonary complications had more severe disease symptoms than the patients who didn’t have lung complications, including enlarged liver or spleen, rash, fever and inflammation around the heart, lungs or abdomen. Further, of those with the lung complications:

  • 92 percent had these systemic symptoms when the pulmonary issues were diagnosed.
  • 80 percent had macrophage activation syndrome (MAS) – a potentially fatal complication that occurs when the immune system goes into overdrive to fight infection, but then doesn’t slow down when the infection is gone.
  • 68 percent of these patients died an average of nine months after being diagnosed with the pulmonary complications.

Researchers say that not enough information is known to be able to say whether the lung complications were triggered by severity of the patients’ disease or whether they may have been influenced by certain medications. But 68 percent of the patients with pulmonary complications were on a biologic medication or had discontinued one within a month of being diagnosed, and 80 percent of the complications occurred after 2004.

“I can’t say that there is a definite relationship to taking any medication, but we do know that patients with systemic JIA were being treated with biologic agents much more frequently after 2004,” Dr. Kimura says.