Juvenile Idiopathic Arthritis: The Most Common Pediatric Rheumatological Disorder

The term arthritis refers to inflammation of a joint which is evident in the form of pain and swelling of the affected joint. It can be acute or chronic arthritis. Acute arthritis is more common than chronic arthritis in children, which usually subside by 4 to 6 weeks. But if it doesn't resolve by 6 weeks, we label a child with chronic arthritis. Juvenile idiopathic arthritis (JIA) is the most common chronic arthritis of unknown cause. Therefore, one should think about JIA for any child with joint pain/joint swelling/early morning stiffness in the affected joint or limping for more than 1 and ½ months of duration. It is the most common rheumatic disease of childhood, affecting 1 in 1000 kids. The term rheumatic suggests that it is related to the dysfunction of the immune system. We all have an inbuilt immune system that protects us against various infections. However, sometimes, it becomes overactive due to an unknown cause and starts harming its own body part. In this process, joints are the most common site of affection. It's the need of the hour to be aware of these diseases as around 5 lac children in our country are suffering from this disease.

Seven types of juvenile idiopathic arthritis have been defined in children based on the number of joints, co-occurrence of fever, psoriasis, rheumatoid factor (RF), and HLA B27. In India, the most common type of JIA in children is either systemic juvenile idiopathic arthritis (SJIA) or enthesitis-related arthritis (ERA), followed by oligoarticular JIA. Systemic JIA can affect children of either sex in all age groups, typically between 1 to 5 years of age. A child with SJIA presents with typically high-grade fever daily for more than 2 weeks, along with pain in joints or joints swelling. Sometimes parents may also appreciate the presence of a fading rash on warm areas of the body such as armpits, groin, or while giving warm water bath. Therefore, one should suspect SJIA in a child who has prolonged fever and is not responding to multiple courses of antibiotics. 

Another category called enthesitis-related arthritis primarily affects boys more than 6 years. They usually complain of pain and swelling of the lower extremity joints, mainly knees, ankles, and feet. Sometimes they can have redness of the eyes concomitantly called acute uveitis (swelling of the middle layer of the eye) or pain in the backbone called sacroiliitis. The majority of them are positive for HLA B27.

Kids with oligoarticular JIA are typically toddler girls. The knees and ankles are the most commonly affected joints. Therefore, one should suspect it in a specifically 2 to 3-year-old girl who refuses to walk or cannot bear weight on her legs after waking up in the morning due to swelling (arthritis) of knees or ankles. But, the vital thing to remember here is the co-existence of chronic silent uveitis, which can be blinding in nature if not detected early. Therefore children having oligoarticular JIA should have regular uveitis screening from an eye specialist as per standard guidelines.

The most important point to highlight is that the various types of juvenile idiopathic arthritis in children respond to various medications better than adults, with good outcomes if diagnosed and treated early. These diseases are best managed by various specialists who are trained and have expertise in the field of pediatric rheumatology. It's very satisfying for the doctor and parents to see that a child who came in a crippling state starts walking within a few days of initiation of therapy and later grows into a normal healthy adult. Many times parents ask about preventive measures for such diseases. All kids should be fully vaccinated against various infections as per the immunization schedule. In addition, they should have healthy eating habits and a healthy lifestyle.

(Dr. Anju Singh, Consultant Pediatric Rheumatologist, Artemis Hospitals, Gurgaon)

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