Joint pain is one of the most common childhood complaints.
The majority of these pains may not be all that dangerous, but sometimes, it may indicate an underlying illness that requires a bit more attention, such as juvenile idiopathic arthritis (JIA).
Childhood arthritis is the term used to describe all instances of pain and inflammation of joints in children, including JIA.
JIA itself is a group of disorders that encompass a wide range of arthritis of unknown cause.
It usually affects children aged 16 and below.
Diagnosis of the disease relies heavily on the duration of the arthritis.
A suspicion of JIA should be raised if the arthritis persists beyond six weeks, and a definite full diagnosis can be made after six months.
This is because the clinical signs associated with the joint pain may change with time and eventually fit into one of the seven subtypes of JIA.
A combination of good history and examination helps with the diagnosis.
However, as JIA is good at mimicking other diseases, it is of utmost importance to exclude these other possibilities first. These include:
This is the most common diagnosis for a child with prolonged multiple joint pains, especially the knees, ankles and wrists, without any joint swelling.
The child usually develops joint pain towards the evening or when triggered by strenuous activity, e.g. exercise, long walks or during writing.
The pain is usually relieved by rest or a massage.
It usually arises from bad habits such as poor posture, incorrect lifting methods and using non-ergonomic chairs.
This severe joint pain usually occurs following infections such as the flu, food poisoning or a urinary tract infection.
The pain will resolve by itself after several weeks.
If the child has high fever, rashes, and loss of appetite and weight, along with the severe joint pain, bone pain needs to be excluded.
This pain is characteristically more severe at night and often wakes the child up.
In this case, joint or bone infection, or even leukaemia, are more likely causes of the problem.
Unfortunately, there is no blood test or imaging that can pinpoint the diagnosis of JIA.
However, certain blood tests like rheumatoid factor (RF) and anti-nuclear antibody may be helpful to ascertain the JIA subtype.
Joint swelling and more
One of the most typical symptoms of arthritis is persistent unexplained joint swelling.
Despite this, most parents find it difficult to identify joint swelling unless it is severe.
The magnitude of the swelling does not always correlate to pain, i.e. a huge swelling does not necessarily cause great pain.
Usually, children experience mild aches after waking up from sleep or a period of rest.
Some may describe the pain as stiffness, as though the joint has “fallen asleep”.
When dealing with toddlers or infants, clumsiness or lack of movement in the affected limb should alert caregivers that arthritis may be present.
Most of the time, parents can identify that their child is not moving their limbs as usual and bring them to the doctor for a consultation.
Sometimes, the arthritis may only develop much later, leading to misdiagnosis.
Furthermore, other illnesses may coexist with JIA, such as Crohn’s disease and psoriasis.
JIA has seven classical subtypes, with each subtype differing with respect to their clinical presentation, inheritance, disease course and response to treatment. They are:
This subtype typically involves four joints or less within six months of the start of the disease.
The commonest joint involved is the knee, and it tends to affect girls more than boys.
At diagnosis, this subtype usually sees more than four joints affected.
It is similar to adult rheumatoid arthritis and affects older children.
It is a lifelong condition, with poorer prognosis and a high risk of joint damage.
The wrists and small joints of the fingers tend to be affected symmetrically.
Patients usually have a family history of rheumatoid arthritis.
Similar to its RF-positive sibling, patients with RF-negative polyarthritis typically have five or more joints affected by the time of diagnosis.
However, it usually strikes toddlers or young adolescents.
The progression is similar to RF-positive polyarthritis, and frequently involves the neck and jaw.
But these patients don’t usually have a family history of rheumatoid arthritis.
This is the only form of arthritis that hits more males than females.
It typically manifests after the age of six and is usually inherited.
This is the rarest group of arthritis and is associated with psoriasis.
This is the most unique and feared subtype of JIA simply because patients are usually very ill and it is difficult to diagnose.
Due to its potential to mimic other diseases, diagnosis is often delayed.
It is characterised by the presence of a peculiar pattern of fever lasting at least two weeks, i.e. a persistent high-grade fever that occurs at the night and resolves by morning.
During the fever, a typical salmon pink rash may appear.
Patients are also quite ill when the fever hits, but become well when it abates.
The arthritis is scattered, involving both large and small joints.
There could be large lymph nodes and swelling of the liver and spleen as well.
In some children, a severe and potentially fatal complication called Macrophage Activation Syndrome can arise if treatment is delayed.
In the end, patients may be left with an eroded joint.
This diagnosis is usually applied when the patient’s symptoms overlap between subtypes, only partially fulfil a subtype or are uncertain.
Further problems
One of the most common complications associated with JIA is uveitis, i.e. inflammation of the uvea – the middle layer of the eye.
This may occur even before the arthritis sets in.
It can present as painless eye redness at first, but if left untreated, will result in blindness.
When the joints are disrupted, they may cause abnormal bone growth, causing unequal length of limbs.
Sometimes, if the inflammation is severe, the growth of the bones may be stunted instead.
This is particularly true in the systemic and polyarthritis subtypes of JIA.
Uncontrolled inflammation of the joint can also progress to bony deformities, contractures, and finally, limited range of motion.
This is caused by erosion of the joint surface, leading to cartilage loss, narrowing of joint space, and finally, fusion of the joint.
The most vulnerable joints are the wrists, fingers, jaw and neck.
Controlling the disease
There is no permanent cure for JIA, but there are ways to control the progress of the disease.
Non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen, naproxen and indomethacin, help to reduce inflammation in the joints and offer pain relief.
Glucocorticoids such as prednisolone, remain one of the most effective treatment options, offering rapid relief.
But prolonged use or high doses can have side effects like growth retardation, osteoporotic fractures, cataracts and frequent infections due to severe immunosuppression.
Disease-modifying anti-rheumatic drugs (DMARDs) can be used in prolonged disease or if steroid-dependent (when the patient’s condition depends on receiving steroid therapy).
Among the DMARDs, methotrexate is the most widely used.
Although very effective, it may also cause nausea, stomach discomfort, fatigue or liver toxicity.
The introduction of biologics in the early 2000s revolutionised treatment, allowing for minimal use of steroids.
Their effectiveness is extremely good, with a quick onset of action and less side effects.
Examples include anti-tumour necrosis factor (aTNF) and interleukin 6 (IL-6) inhibitors.
Apart from medication, good, consistent rehabilitation and physiotherapy are very important for patients.
The aims of physiotherapy are to strengthen the muscles and improve the range of joint motion.
JIA remains one of the most frequently-missed chronic diseases among children.
Over the past few decades, advances in medicine have helped with control of the disease and enabled a reduction in physical disability.
Early recognition and aggressive treatment remain the key to full remission.
Dr Koay Beng Siang is a paediatric rheumatologist. For more information, email starhealth@thestar.com.my. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
Already a subscriber? Log in
Get 20% OFF The Star Digital Access
Cancel anytime. Ad-free. Unlimited access with perks.
