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Editorial Indian Pediatrics 2003; 40:393-397 |
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Chronic Arthritis: Current Perspectives |
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Juvenile chronic arthritis (syn. juvenile rheumatoid arthritis) is the commonest rheumatological problem seen in children(1-4). Epidemiological studies conducted in the West suggest that the prevalence of this condition may be in the range of 2-11/1000 children below 15 years of age. If these figures are correct, it may suggest that juvenile chronic arthritis (JCA) may, in fact, be as common a pediatric condition as rheumatic arthritis. Yet, it is a fact that many children with this condition in India (as also in many other developing countries) are not given this diagnostic label and continue to be mistreated as tubercular arthritis or even as rheumatic arthiritis in some cases! The differential diagnosis of a child with chronic arthritis can be very broad and a large number of conditions can mimic the clincial features of this conditon(5-12). However, with some experience it is not difficult to exclude most of these conditions on the basis of a good clinical history and physical examination(13-15). Terminology The terminology pertaining to chronic arthritis in children may appear a little confus-ing. The American College of Rheumatology (ACR) uses the term Juvenile Rheumatoid Arthritis( JRA) while the European League Against Rheumatism prefers the term Juvenile Chronic Arthritis (JCA). The International League of Associations for Rheumatology (ILAR), however, have adopted the term Juvenile Idiopathic Arthiritis (JIA) to characterize children having arthritis persist-ing beyond 6 weeks and having no known cause(16). However, it is important to remember that from the clinician’s point of view the simplest classification is the one given by the American College of Rheumato-logy (ACR). This is still widely used by many rheumatologists and is notable for its simplicity and clarity(13,15). The ACR and ILAR classificlations are summarized in Tables I & II. The ILAR classification, in particular, is tedious and difficult to apply in a busy outpatient clinic. Table I ACR Classification of Juvenile Arthritis
Table II Juvenile Idiopathic Arthritis (JIA) - Durban Classification
Table III Doses of NSAIDs in JRA
Treatment The treatment of chronic arthritis is difficult and has to continue long-term just as is the case in adults with rheumatoid arthritis. However, many parents are unable to accept this fact because of the misconception that most children would ultimately get well on their own - this is certainly not true. The course of the disease is notoriously unpredict-able and may be marked by unexpected exacerbations and remissions. Non-steroidal anti-inflammatory drugs (NSAIDs) form the cornerstone of management of these children(15). A large number of these are available in the market but the preferred ones in children are only 3: naproxen, ibuprofen and tolmetin. NSAIDs inhibit both COX-1 and COX-2, but drugs specifically inhibiting only the latter have still not been validated in children. The doses of commonly used NSAIDs are given in Table III. A reasonable trial of NSAIDs would mean monotherapy for a period of 3-4 months in appropriate doses. The anti-inflammatory dose of most NSAIDs is 2-3 times the analgesic dose. The response is usually slow and many children may continue to be symptomatic even after 4-6 weeks of therapy. This should not mandate change of therapy. It is also not advisable to add a second NSAID if response to the first is less than appropriate. However, idiosyncratic reactions are well known and a given patient may respond to one NSAID and not to the other. Both the physician and the family have to exercise patience, discretion and caution in selecting the most appropriate NSAID and waiting for its response. It must be made clear to the parents that NSAIDs do not modify the natural history of the disease and, therefore, would not prevent joint damage. These drugs only provide relief from pain and are anti-inflammatory. While using these the physician is, in fact, merely buying time and waiting for a natural remission of the disease to occur. The only drug, which can modify the natural course of the disease, is methotrexate and it is almost considered to be the drug of choice in children who fail to respond to a reasonable trial of NSAIDs. It is usually given orally in a dose of 10-30 mg/m2 once every week, empty stomach(17,18). It is proven to be safe in children and has been in regular use since the early nineties. Its major advantage is that it is neither gonadotoxic nor oncogenic. It is efficacious and between 50-75% children achieve a remission. Significant hepato-toxicity (occasionally fatal) is a known complication and the parents must be warned accordingly. Salazopyrine is preferentially used in children with spondyloarthropathies. Other DMARDs like gold and penicilla- mine are not frequently used in children now-a-days. The other commonly used drugs in children with JRA are the corticosteroids. Oral prednisolone is often required in children with systemic onset JRA as also in some patients with polyarticular disease. When used for the latter it is given as bridge therapy for a few weeks till the methotrexate begins to exert its disease modyfing action. Intra-aritcular corticosteroids (usually triamcino-lone) are sometimes used in children with pauci-articular disease specially when the involve-ment is restricted to large joints like the knee. Intravenous pulses (usually given over 3-5 days) of methylprednisolone/dexamethasone can be used in patients with life threatening forms of JRA (e.g., with pericarditis, vasculitis) or where the systemic manifesta-tions are very prominent. Local steroid drops are used for the treatment of iridocyclitis. A number of newer forms of therapy have been proposed for use in adult onset rheumatoid arthritis and some of these may turn out to be useful even in children with JRA. Leflunomide is a pyrimidine synthesis inhibitor and appears to be a promising agent. It is a useful add-on drug when used as an adjunct with methotrexate. Infliximab is an antibody to tumor-necrosis factor (TNF)-alpha. It is highly effective but has not been used frequently in children. Etanercept is a recombinant human tumour necrosis factor receptor Fc fusion protein. It has been used in children showing a less than adequate response to methotrexate. It may be noted that these drugs have not been frequently used in India till date and should only be considered in children not responding to a reasonable trial of methotrexate(19-21). Follow-up and Prognosis Long term prognosis of JRA depends on the pattern of joint involvement in the first 6 months of onset of the disease(22-24). Children with pauciarticular disease tend to have a much more benign course as compared to the aggressive rheumatoid factor positive polyarticular disease. However, the former can have disabling (and in some cases blinding) iridocyclitis which can run an insidious but relentlessly progressive course. Development of secondary amyloidosis is also a concern especially in children with active ongoing inflammation(25). Chronic arthritis in children is still a difficult condition to manage. It is considered to be a common cause of morbidity and school absenteeism in children. In spite of the many advances in therapy, 20-30% of children with JRA will continue to have features of active arthritis even as adults (26,27). However, the long-term outlook of this condition is now much more favorable than was the case a couple of decades ago. A number of highly effective and exciting new therapies are in the offing and these may completely change the outlook of this disease. Surjit Singh, | ||||||||||||||||||||||||||||||||||||||
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