Complications and Comorbidities in Systemic Juvenile Idiopathic Arthritis

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Children living with systemic juvenile idiopathic arthritis (SJIA) can face many health challenges. New medical conditions may arise because of the disease itself (considered a complication) or occur along with the primary disease (considered a comorbidity). These health challenges are largely triggered by systemic inflammation and some medications designed to treat the underlying disease.


A few decades ago, joint damage and disability were the main complications of SJIA. That’s no longer true for the majority of kids, but growth and lung problems can occur.

  • Bone problems. Persistent inflammation of the joint lining can interfere with normal bone growth, causing one arm or leg to be longer than the other and slowing or stunting overall growth. At the American College of Rheumatology symposium on SJIA in (year), it was reported that almost half of patients with SJIA are more than two standard deviations below their target heights. To prevent these issues, doctors try to bring inflammation under control as fast as possible, usually with high-dose corticosteroids, says Theresa Wampler Muskardin, MD, pediatric rheumatologist at Hassenfeld Children’s Hospital at NYU Langone Health in New York City. The problem is that corticosteroids like prednisone can stop kids from growing normally, too. One solution is to switch to nonsteroid treatments, such as traditional disease-modifying drugs and biologics,  as soon as inflammation calms down. Most doctors start kids on bone-protective calcium and vitamin D supplements, too. Growth hormones may also be an effective option for children who are slow to grow. In some cases, a physical or occupational therapy may be helpful to project joints and preserve mobility.
  • Macrophage Activation Syndrome (MAS). The most serious complication of SJIA, MAS is a life-threatening inflammation that overwhelms the  body. Known triggers for MAS include infections, a disease flare or  certain drugs used to treat SJIA. The syndrome can come on very quickly and be fatal without prompt treatment. Recognizing signs of MAS and getting a prompt and accurate diagnosis is critical.

  • Lung problems. In recent years, doctors have seen an increase in serious lung diseases among kids with SJIA, including pulmonary arterial hypertension and interstitial lung disease. Pulmonary hypertension is high blood pressure that affects the arteries in the lungs and the right side of the heart. Interstitial lung disease causes scarring of lung tissue, making it harder to get oxygen into the bloodstream. Though rare, these diseases have no cure and can be life threatening.  Treatment is complex and may involve oral or inhaled medications, oxygen therapy and pulmonary rehabilitation, which teaches kids breathing techniques and lifestyle changes that may help them feel better. Yukiko Kimura, MD, a pediatric rheumatologist at Hackensack University Health Network in New Jersey, says it’s not certain why more children are developing these diseases. Research by Dr. Kimura and others has shown that many kids have MAS or very severe SJIA symptoms when they’re diagnosed with lung disease, and most have taken powerful arthritis drugs.


Studies have shown that a significant number of kids with SJIA have at least one comorbidity, and they’re more likely to have fatigue, pain and a lesser quality of life than those who don’t. The most common co-occurring conditions in SJIA are heart-related. In a study reported in the Sept/Oct 2013 issue of Clinical and Experimental Rheumatology, around 10 percent of kids with other types of juvenile arthritis had heart problems compared to nearly 41 percent of those with SJIA.   

  • High blood pressure (hypertension). This is one of the most common comorbidities in SJIA, and it can occur for at least two reasons. One is atherosclerosis – the buildup of fatty deposits on artery walls. When the arteries narrow, the heart has to pump harder to move blood through them. Although atherosclerosis can develop in healthy children, it’s seen more often in SJIA – likely due to ongoing inflammation.  But Dr. Wampler Muskardin says a more frequent cause of high blood pressure is treatment with corticosteroids, which cause fluid retention and weight gain. “The aim is to transition to a corticosteroid-sparing treatment as soon as possible,” she says, noting that it’s uncommon for kids to need high blood pressure medication.

  • Osteoporosis. Like high blood pressure, osteoporosis can result from long-term inflammation or from treatment with corticosteroids. Both can make bones weaker and more likely to break. Bone loss begins within the first three months of corticosteroids, even at low daily doses. According to a study published in the Annals of Rheumatic Diseases in 2016, 6 percent of children with juvenile arthritis had a fracture after taking steroids for one year, and the risk was even higher for those with SJIA. “Minimizing the use of these drugs can reduce the risk, but patients aren’t always able to come off steroids when we would like them to,” explains Daniel Lovell, associate director of rheumatology at Cincinnati Children’s Hospital Medical Center. For that reason, many doctors start calcium and vitamin D supplements from the beginning.  It’s also important to make sure kids get plenty of physical exercise – one of the best ways to ensure strong, healthy bones. Poor nutrition can also be a contributing factor. So, eating calcium and vitamin D-rich foods such as dairy, broccoli, salmon and oranges are also important.

Complications and comorbidities associated with SJIA can’t always be prevented. But experts say keeping inflammation well controlled and weaning kids off steroids as soon as possible may provide some protection.


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