British Journal of Rheumatology 1993,32:421^123
PAEDIATRIC RHEUMATOLOGY
SERIES EDITOR: P. WOO
EDITORIAL
CHILDHOOD ARTHRITIS: THE NAME GAME
labels should facilitate the precision and
brevity of communication. Unfortunately diagnostic
labelling which is indiscriminate, inaccurate, or inflexible has many disadvantages. If one diagnostic label is
found to cover a plethora of diseases, or one disease is
covered by a number of diagnostic labels, then a morass
of bewildering jargon may result and the understanding of disease delayed or even prevented. Confusion
over disease labelling is one of the problems facing all
concerned with the care of children with arthritis.
Currently there is no internationally recognized and
scientifically valid system of nomenclature for the
chronic arthritides of childhood.
Arthritis can be a presenting manifestation of a large
and heterogeneous group of diseases. These include
autoimmune and connective tissue diseases, sepsis,
non-accidental injury, leukaemia, metabolic and inherited diseases, bleeding diatheses and immunodeficiency. In other words, arthritis is a clinical feature, not
a disease. The diagnosis of which disease is causing
arthritis in a child is difficult enough without the shortcomings of the current labels for chronic arthritis. The
aims of this editorial are to outline the problems with
this nomenclature, and to propose a system which
might overcome some of these deficiencies.
disease; psoriasis; inflammatory bowel disease;
enthesitis; chronic anterior uveitis or iridocyclitis;
acute conjunctivitis; urethritis.
6. The presence of spinal or sacroiliac inflammation.
7. Serological associations: antinuclear antibodies
(ANA); rheumatoid factors (RF); anti-streptococcal antibodies (e.g. ASOT), other serological infective screens.
8. HLA associations: class I (B27); class II (DR5, DR8,
DR4, DPw2.1).
9. Radiological associations: erosive; non-erosive.
Even the classical subdivision on the basis of the
number of joints involved during the first 6 months of
the disease could also be questioned. At least a third of
children with pauciarthritis at onset develop polyarthritis with time, and HLA data suggest that these
patients are genetically distinct from persistent pauciarticular, and polyarticular disease [6].
The terms JCA, JRA, Still's disease and JA are not
strictly interchangeable. Still's disease is now regarded
as a historical term, although it is occasionally used to
describe chronic arthritis with systemic features. JRA
specifically excludes psoriatic arthritis, the spondyloarthropathies, and arthritis associated with inflammatory
bowel disease, all of which are included under the label
JCA. Both JCA and JRA are diagnoses of idiopathic
arthritis by exclusion, whereas a recent publication has
suggested that JA covers arthritis associated with
defined causes such as malignancy or congenital bone
dysplasias [7]. Such a broad, non-specific umbrella
term is unlikely to be useful in enhancing
communication.
The present labels have misleading or undesirable
connotations. The term 'juvenile' can be criticized on
several levels. Although the maturational state of the
musculo-skeletal and immune systems is almost certainly important in the aetiology and outcome of arthritis, labelling on the basis of an arbitrary age limit
(disease onset at less than 16 years of age) is unlikely to
be biologically relevant. In addition, adolescents with
arthritis do not appreciate the name 'juvenile' and the
unfortunate derivative 'junior' implies a less serious or
even unimportant disease. In JRA, 'rheumatoid'
implies a close similarity with RA in adults, when in
fact only a small minority (5-10%) of patients with
JRA have a RF positive, symmetrical, erosive polyarthritis. The designation 'chronic' in JCA is also seen
as perjorative, suggesting a life-long affliction for which
little can be done. There is also a lack of consensus
about the time beyond which the arthritis could be
classified as 'chronic'; three months in the definition of
JCA, six weeks for JRA. In either case, the time limits
appear to be arbitrary, and unlikely to be of biological
relevance.
DIAGNOSTIC
THE DEFICIENCIES OF THE CURRENT
NOMENCLATURE OF CHRONIC ARTHRITIS
IN CHILDREN
There are no consistent, internationally accepted
diagnostic labels for children with persistent arthritis.
In the UK, France and most other European countries,
they would be labelled as juvenile chronic arthritis
(JCA) [1]. However, in a few European countries and
most of the USA, juvenile rheumatoid arthritis (JRA)
[2] would be used. Other centres throughout the world
use the terms juvenile arthritis (JA) [3], or even Still's
disease [4].
None of the above refer to one homogeneous disease
[5]. Each term covers several diseases which can be
defined clinically and in some cases serologically and
genetically. The clinical and laboratory parameters
which have been used to subdivide chronic arthritis
include:
1. Disease pattern at onset of arthritis (during the first
6 months): pauci- and poly-articular onset (<4
joints, >4 joints respectively; systemic onset.
2. Disease pattern during the course of the disease:
extended
pauciarticular;
pauci-polyarticular
disease.
3. The description of the arthritic joint: dry; boggy.
4. The age at onset of arthritis: early onset (<6 years);
late onset (>6 years).
5. The presence of extra-articular features: systemic
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© 1993 British Society for Rheumatology
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BRITISH JOURNAL OF RHEUMATOLOGY VOL. 32 NO. 5
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The current nomenclature is inflexible, and does not
provide a system for refinement based on either the
clinical evolution of disease in individual patients, or
advances in scientific knowledge about the diseases in
general. Little account is taken of the fact that some
patients may not develop all the 'diagnostic' clinical
features simultaneously. For example, many years may
elapse between the onset of peripheral arthritis and the
onset of psoriasis [8] or the lack of involvement of the
spine in spondyloarthritis [9, 10].
TIME FOR CHANGE
There is concensus that the nomenclature of childhood arthritis needs to be re-evaluated, but some
would maintain that it is premature to attempt this task
before the diseases are better understood. With the
rapid advances being made in the detailed analysis of
HLA and its associations with childhood arthritis
(reviewed in [11]), it could be argued that just a few
more years may render nomenclature arguments
redundant. However, no HLA associations or other
laboratory investigations have so far proved diseasespecific. It is a worrying possibility that any disease
specificity may be obscured by the imprecision of the
current disease labels. To attempt to remedy this situation, it would seem opportune to address the problems of nomenclature now, rather than procrastinate.
Umbrella terms such as JA, JRA or JCA should not
be used. Those who believe that such terms are useful
for communicating with people not working in the field
of paediatric rheumatology could consider just referring to 'arthritis in children' to describe the common
clinical feature of the whole group of diseases. For communication among paediatric rheumatology cognoscenti, non-specific umbrella terms appear to have so
little clinical, therapeutic, prognostic, or indeed biologic value, that they are useless in isolation.
The ultimate aim of the proposed new system of
nomenclature is to allocate an individual label to each
disease which causes arthritis in children. Of course, a
major limitation of defining labels by aetiology at present is that the causes of most arthritides are unknown!
A more achievable, immediate aim of the proposed
system is to increase the biological homogeneity of
patients classified under any particular label. This may
be accomplished in two ways:
1. By using strict criteria for each label to specify diseases of clinical homogeneity (recognizing that the
more restrictive the criteria, the more arthritic diseases may remain unclassified).
2. By building in theflexibilityto refine the criteria and
reassign patients to more specific disease categories.
Another problem is to use labels which clearly discriminate one disease from another. The new system
must remain clinically relevant, so clinical features
have been used as the primary criteria for the diag-
TABLE1
1.
Systemic arthritis
2.
Uveitis related arthritis
Definite
Probable
Arthritis
characteristic rash
>2 wk of quotidian fever
2.1 Uveitis and oligoarthritis
onset <6 yr
[•HLA DRP0801]
[
DPP0201]
2.2 Uveitis and extending
arthritis
2.3 Uveitis and polyarthritis
onset <6 yr ANA pos
[•HLA DRf30801]
[
DRP1301]
Radiological sacroiliitis
and
Lower limb oligoarthritis onset >6 yr
Typical rash and fever, organomegaly and/or
lymphadenopathy and/or serositis in the absence
of arthritis
3.
Spondyloarthritis
4.
Psoariasis related arthritis
5.
Inflammatory bowel related
Inflammatory bowel disease lower limb
arthritis
oligoarthritis
Symmetrical polyarthritis [16] 6.1 Rheumatoid factor pos
and HLA DR4/DR1
6.2 Rheumatoid factor neg
Mixed arthritis
6.
7.
Psoriasis and arthritis
2.1 or 2.2 or 2.3 in the absence of uveitis
Lower limb oligoarthritis onset >6 yr
and
Enthesitis, or HLA B27 positive, or positive
family history of ankylosing spondylitis
Positive family history of psoriasis, and one of the
following: nail pitting, or psoriasis-like rash, or
dactylitis,
•Associated genetic patterns, but not to be used as diagnostic as yet.
Note 1: The 6 yr. cut off age limit may need adjustment in the light of further genetic data.
2: For the diagnosis of any of the above all mimics must first be excluded.
PAEDIATRIC RHEUMATOLOGY: EDITORIAL
noses. In the absence of primary criteria however, diagnoses may still be made with combinations of
secondary criteria (e.g. genetic and serological features). The groups will be more homogeneous in terms
of current clinical, serological and genetic knowledge.
Further subdivisions or mergers can be made according
to newer genetic information, for example different
mutations of a single gene like collagen type III can
produce a spectrum of clinical manifestations.
A PROPOSED SYSTEM OF NOMENCLATURE
FOR THE ARTHRITIDES OF CHILDHOOD
This system could include all of the diseases which
may cause arthritis in children (reviewed in [12]). However, the outline in Table I will not list those arthritic
diseases for which the cause is known, such as septic
arthritis or leukaemic arthritis, and will instead be limited to those conditions which are currently 'idiopathic'. The suggested name for the disease is listed
first, followed by the definite and probable criteria for
the diagnosis. In all cases, arthritis must be present
before the definite diagnosis can be considered, and
other causes of arthritis must have been ruled out. If
any patient fulfills the criteria for more than one diagnosis, then he/she would be assigned a 'mixed' diagnosis. Oligoarthritis and polyarthritis refer to the
number of joints affected during the first 6 months of
disease (four joints or less, or more than four joints
respectively). Extending oligoarthritis refers to
patients who had a polyarticular disease course after
initial oligoarthritis.
CONCLUSION
It is clear that this proposed system will need to be
validated, and changed as a result of the validation process. Perceived associations may not have any biologic
relevance and may obscure the 'real' association. However, if any classification can increase the homogeneity
of disease groups and allow greater predictive accuracy, it would seem a worthwhile basis for discussion.
We hope that the views expressed in this Editorial will
stimulate further constructive debate on the subject.
ACKNOWLEDGEMENTS
We would like to thank Drs B. M. Ansell, A. Hall, P. Hollingworth, J. Sills and M. Rooney for helpful discussions.
T. R. SOUTHWOOD* AND P. Woof
^Childhood Arthritis Unit, Department of Rheumatology, University of Birmingham, Birmingham B15 2TT;
fMolecular Rheumatology Section, MRC Clinical
Research Centre, Watford Road, Harrow, Middlesex
HA1 3UJ
423
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