The Journal of the Arkansas Medical Society Med Journal Jan 2019 Final 2 | Page 17

A Review of Juvenile Idiopathic Arthritis
for the General Practitioner
Sukesh Sukumaran, MD
Assistant Professor of Pediatrics, Division of Rheumatology,
Department of Pediatrics, UAMS, Arkansas Children’s Hospital, Little Rock
Introduction
J
uvenile Idiopathic Arthritis (JIA) is
defined as chronic arthritis persist-
ing six weeks or longer with onset
before the age of 16 years. 1 This was previ-
ously known as juvenile chronic arthritis or ju-
venile rheumatoid arthritis. The terminology has
been replaced by JIA to underscore the fact that
arthritis in childhood is a distinct disease and
differs from adult-onset rheumatoid arthritis.
The pathogenesis and etiology of JIA are
unclear but thought to be due to multifacto-
rial interactions among genetic factors, immune
mechanisms, and environmental exposures.
Most of the genetic predisposition to JIA is de-
termined by the major histocompatibility com-
plex loci. Several potential pathogens have been
proposed but none have been definitely shown
to be casual. 2
The estimated incidence and prevalence of
JIA in the U.S. is approximately 14 per 100,000
children (95% confidence interval: 10–18) and
113 per 100,000 (95% confidence interval: 55–
155), respectively. 3 However, to care for these
patients, there are <300 practicing pediatric
rheumatologists in the U.S. and only two pedi-
atric rheumatologists in Arkansas. 4 The shortage
of board-certified pediatric rheumatologists has
made it necessary for primary care physicians to
assume the care of many children with JIA and
other rheumatologic diseases. Therefore, it is im-
portant for these physicians to be familiar with the
clinical presentation and evaluation of children
with JIA as they are likely to encounter these chil-
dren in their practice.
This article provides an update on identifi-
cation of JIA, management strategies, and po-
tential complications of the disease.
Classification of JIA
The International League of Associations for
Rheumatology classification (ILAR) categorizes
JIA into seven subtypes based on the number
of joints involved, extra-articular features, and
serology identified in the first six months of dis-
ease presentation. 1 The features of each type are
summarized in Table 1.
Clinical Features
JIA is a clinical diagnosis and there is no de-
finitive diagnostic test. Exclusion of other causes
of arthritis such as infections, malignancy,
trauma, reactive arthritis, and connective tissue
diseases such as systemic lupus erythematosus,
is critical before making a diagnosis of JIA. 1, 2, 5
Clinical features that are suggestive of JIA
include presence of morning stiffness for > 15
minutes with improvement after activity, stiff-
ness after prolonged periods of inactivity, and
decreased range of motion of the joints. It is
important to recognize that toddlers may not
present with classic features of arthritis. Parents
often describe that the child is fussy in the morn-
ing or refusal to use certain extremities. Fever,
malaise, weight loss, night sweats, bone or joint
pain, generalized pain, refractory or unremitting
pain, nighttime pain should raise concern about
infection or malignancy, and a work-up for these
conditions must be performed immediately.
All joints must be examined for the pres-
ence of arthritis (i.e, swelling, warmth, restricted
range of motion, or tenderness with range of mo-
tion). On careful observation of the child, prefer-
ential use of certain extremities may be noted.
Signs of chronic arthritis include the presence
of muscle atrophy due to disuse, bony over-
growth due to hyperemia of the area, leg length
discrepancy, and micrognathia or retrognathia
due to temporomandibular joint involvement. 1, 2,
5
Documentation of the number of joints involved
is important for categorizing type of arthritis. 1
Enthesitis-related arthritis is more com-
monly seen in males and generally presents with
axial involvement of the spine or sacroiliac joints
and “enthesitis” or inflammation at the sites at
which tendons or ligaments insert onto bone.
Most commonly involved areas include the achil-
les tendon, greater trochanter, metatarsal heads,
and planter fascia insertion on the feet. Nail pit-
ting, psoriasis, dactylitis, or “sausage digits” are
suggestive of psoriatic arthritis.
Uveitis or inflammation of the eyes in chil-
dren with JIA is often asymptomatic and hence
children with JIA must be regularly screened
for uveitis by an ophthalmologist. The American
Academy of Pediatrics has published guidelines
on the frequency of ophthalmological examina-
tions based on child’s age of diagnosis and ANA
positivity. 6,7 These recommendations are sum-
marized in Table 2.
Systemic-onset JIA
The clinical presentation of systemic-onset
JIA (SoJIA) differs remarkably from other cat-
egories of JIA. The typical presentation is daily
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