Would it surprise you to know arthritis in children can affect only one joint with swelling and yet still be pain free? That’s one of the reasons it is so difficult to make the diagnosis. Those symptoms can also describe other conditions such as Lyme disease, tuberculosis, tumor, lupus, and even inflammatory bowel disease.
Dr. Marilynn Punaro from the Texas Scottish Rite Hospital for Children and University of Texas Southwestern Medical Center in Dallas, Texas provides this in-depth look at arthritis in children. Dr. Punaro reviews the diagnostic criteria for all of these conditions to help the pediatrician make an accurate diagnosis.
The arthritic condition used to be called juvenile rheumatoid arthritis or JRA but it has been renamed juvenile idiopathic arthritis (JIA). The word “idiopathic” means “of unknown cause.”
Rheumatologic diseases can be difficult to recognize at first. There isn’t one blood test that tells all. Tests used more reliably in adults to look for rheumatoid arthritis (e.g., rheumatoid factor, antinuclear antibody or ANA) are usually negative in children or are a false-positive (positive when there is no rheumatologic disease present at all). X-rays and other imaging studies have equally limited value. The diagnosis really depends on the child’s history and clinical presentation.
The well-trained physician will recognize a telltale pattern of history, signs, and symptoms that will point to juvenile idiopathic arthritis (JIA). In the process, these other possibilities (infection, tumor, other inflammatory diseases) will have to be excluded or ruled out.
When there is pain, finding out what makes the pain better or worse can be helpful. For example, pain that is worse after activity is more likely to be mechanical — meaning a tendon or muscle problem like patellofemoral syndrome. Pain that is worse at night after going to sleep for several hours is a red flag for tumor or growing pains.
Pain with weight-bearing is not a typical pattern with juvenile idiopathic arthritis (JIA). Pain that moves around from joint to joint is another tip-off that the problem isn’t JIA. A hot, tender, swollen joint is more common with infection or trauma. And the presence of extra-articular symptoms points to other conditions.
Extra-articular means “outside the joint” and includes such things as fever, nausea, vomiting, weight loss, elevated blood pressure, skin rash, sores in the mouth, redness of the eye(s), or sudden muscle weakness. When these kinds of signs and symptoms are present, blood tests and urinalysis may be more valuable in identifying the underlying cause.
All of this tells us what is NOT juvenile idiopathic arthritis (JIA). So what does the physician look for that tells him or her that the problem is really JIA? It goes back to something called pattern recognition.
The pattern looks like this: persistent swelling and loss of motion in at least one and up to four joints for six weeks or more. Morning stiffness and limping are more common than actual pain. The child feels well and does not complain of fatigue.
There are several subtypes of juvenile idiopathic arthritis (JIA) but the majority of children with this condition are girls. For every one male with JIA, there are five girls affected. The first symptoms start to show up early (ages one to three). The knee and ankle are involved most often.
Dr. Punaro concludes that diagnosing juvenile idiopathic arthritis (JIA) in children is a challenging task. The physician spends more time making sure it isn’t something else before being certain it is JIA.
After reviewing the history, examining the child, and taking all the tests, the diagnosis is tested out by treating the problem and waiting to see what happens. Symptoms that do not respond to nonsteroidal antiinflammatory drugs (NSAIDs) signal a need to re-evaluate and test further. As shown in this article, knowing what to look for with JIA as well as all the other conditions that look like JIA is essential.