Juvenile Rheumatoid
Arthritis (JRA)
JRA, which is a unique clinical entity
and distinct from rheumatoid arthritis,
affects 148-167 per 100,000 children;
68
it is the most common cause of acquired
disability in children. In JRA, the overall
inflammatory process causes swelling of
joints and is often accompanied by pain,
rash, and loss of mobility. The disease
is classified into three types: pauciarticular
onset, polyarticular onset, and systemic
onset, each with its own set of symptoms
and prognoses.
Subtypes
Pauciarticular
Pauciarticular onset, or oligoarticular
onset, is the most common form of JRA
accounting for 35 percent to 50 percent
of all JRA cases. 68
By definition, pauciarticular JRA affects
four or fewer joints and is most often
limited to the larger joint---the knee,
elbow, or ankle. 68
The effects of this form are usually
asymmetrical and symptoms include swelling
of the affected joints, stiffness, and
mild pain. The peak age for diagnosis
is between 1 and 3 years of age; it affects
females more commonly than males, the
ratio of females to males being 4-5:1.
68
In addition to joint inflammation, in
approximately 10-20 percent of the cases
pauciarticular JRA is associated with
anterior uveitis (i.e., inflammation of
the anterior portion of the uveal tract
of the eye). Uveitis most often occurs
in patients who develop pauciarticular
JRA before the age of 2 and who are ANA
positive (i.e., their blood tests positive
for antinuclear antibodies). Symptoms
of uveitis may occur for many years after
the joint-related symptoms of JRA have
remitted and may be relapsing or chronic.
68
Patients who fit this classification
should be monitored regularly by an ophthalmologist
who is familiar with the effects of JRA.
68
The prognosis of pauciarticular JRA is
the most favorable of all three forms
infrequently resulting in permanent disability
or joint damage. However, 10-20 percent
children with pauciarticular onset go
on to develop polyarticular JRA (i.e.,
arthritis that affects five or more joints),
sometimes called extended oligoarticular
JRA. Long term sequelea of pauciarticular
JRA are more common for those who develop
the disease at a younger age. 69
For those who develop chronic uveitis,
vision problems may persist for many years
after joint inflammation has subsided
and permanent eye damage may occur.
Polyarticular
Polyarticular juvenile rheumatoid arthritis
affects five or more joints; the overall
symptoms are similar to those of adult
rheumatoid arthritis. About 40 percent
of children with JRA have this form, with
girls accounting for approximately 80
percent of cases. 68
It occurs in two peaks, early childhood
and adolescence. While it typically affects
the small joints in the hands, it can
also affect larger joints or the knee,
ankle, hips, neck, and jaw. Polyarticular
JRA is a symmetrical form of arthritis
and can potentially inhibit growth in
affected joints. Many children experience,
for example, retarded growth of their
temporomandibular joint (TMJ), which causes
pain while chewing and brushing; this
can lead to decreased appetite and dental
problems.
Other symptoms of polyarticular JRA can
include low-grade fever, anemia, and inflammation
of internal organs. Chronic uveitis,
occurring in 10 percent of children, is
less common in children with this form
of JRA. 68
The prognosis of this form is dependent
on the number joints affected and the
degree of inflammation. The disease manifestations
of polyarticular JRA often continue into
adulthood and, similar to pauciarticular
JRA, those who experience onset at an
earlier age are more likely to see a longer
duration of the disease. 69
Systemic Onset
Systemic onset JRA is the least common,
but most virulent, form of JRA; it affects
between 10 and 20 percent of children
with JRA and strikes boys and girls at
equal rates. 68
The most common symptoms include persistent
high-grade fevers, rash, and arthritis
of multiple joints. Systemic onset JRA
can also cause inflammation of the outer
lining of the internal organs (most often
the heart and lungs), anemia, high white
blood cell and platelet counts, and enlarged
lymph nodes, liver, or spleen. Macrophage
activation syndrome is an uncommon and
potentially fatal complication; uveitis
is uncommon with systemic onset JRA.
The prognosis of systemic onset JRA varies
widely. One study shows that, unlike
pauciarticular and polyarticular JRA,
younger age at onset appears to indicate
a shorter duration of active disease.
69
Some cases remit within one year but
recurrent flare-ups are common. Up to
30 percent of cases disappear completely
with no long-term effects, but approximately
one-half of cases worsen with time and
are marked by increasingly destructive
arthritis. 68
Table
A.1: Characteristics of Juvenile Rheumatoid
Arthritis Subtypes
Characteristics |
Pauciarticular
Onset |
Polyarticular
Onset |
Systemic
Onset |
Percentage of
JRA cases |
35-50% |
35-45% |
10-20% |
Female/Male ratio |
4-5:
1 |
3-4:
1 |
1:
1 |
Typical age of
onset |
1-3 years |
Variable/early
and late childhood |
Variable |
Number of joints
involved at onset |
4 or fewer |
5 or more |
Variable |
Pattern of joints |
Large; Asymmetrical |
Any; Symmetrical |
Any; Symmetrical |
Risk of uveitis |
High |
Medium |
Low |
Disease duration
with early onset |
Longer |
Longer |
Variable |
Overall Prognosis |
Minority progress
to destructive arthritis |
Half progress
to destructive arthritis |
Some remit completely;
some worsen to severe arthritis |
Other Pediatric Rheumatology Diseases
Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE), commonly
known as lupus, is an autoimmune disease
that typically affects the joints, skin,
kidneys, heart, lungs, blood, and central
nervous system. Symptoms vary greatly
across individuals, ranging from fatigue,
high fever, skin rashes, and swollen joints
to kidney failure, seizures, and cardiac
and lung disease. The Lupus Foundation
of America estimates that approximately
1.4 million Americans have some form of
the disease. 70
More than 85 percent of patients are
women and SLE is most common among minorities,
with African American women experiencing
the highest incidence. 71
While it is rare for lupus to be diagnosed
in pre-pubescent individuals, the Arthritis
Foundation estimates that in the United
States approximately 25,000 children and
adolescents have the disease. 72
There are three other less severe types
of lupus: discoid lupus erythematosus,
drug-induced lupus, and neonatal lupus,
the rare form that affects newborns of
women with lupus.
The overall prognosis for SLE is improving
over time with 5-year survival rates increasing
from 50 percent in 1950 to 80-90 percent
in the 1990s; 73
some statistics now show the 10-year survival
rate at 90 percent, which is believed
to be a result of improved medical care.
68
The treatment of SLE involves the use
of NSAIDs, corticosteroids, antimalarials,
and immunomodulating drugs. The side
effects of some of the drugs can be serious,
including weight gain, osteoporosis, anemia,
high blood pressure, and immunosuppression,
which increase susceptibility to infections.
Immunosuppression is a particularly vexing
problem as several studies have found
infection to be the most common cause
of death in SLE. 74,
75
Much like children with JRA, children
affected by lupus require close medical
supervision to monitor medication side
effects and disease flares and access
to a continuum of collaborative care across
several areas of medicine, including nephrology,
cardiology, and others.
Other Diseases
There are dozens of rare rheumatic diseases
that can affect children. A few of the
more common kinds are:
- Juvenile Psoriatic Arthritis
– characterized by nail pitting, psoriatic
rashes behind the ears, on the eyelids,
and other atypical areas. Long-term
effects include permanent joint damage
and decreased range of motion and eye
problems.
- Juvenile Vasculitis – variants
include polyarteritis, Wegener’s granulomatosis,
and Takayasu’s arteritis, but the most
common symptoms include rash, arthritis,
lung problems, abdominal pain, and renal
dysfunction. More serious cases can
involve major organs, nerves, and the
intestinal tract. Some forms are more
common in boys.
- Juvenile Scleroderma – thickening
of the skin caused by increased collagen
deposits that can lead to growth abnormalities,
loss of skin elasticity, and Raynaud’s
phenomenon. Disease can be localized
or systemic, affecting multiple organs,
and affects more girls than boys.
- Juvenile Dermatomyositis (JDMS)
– skin rash and weakened muscles caused
by inflamed blood vessels in skin and
muscle tissue. Affects 3,000-5,000
children in the United States.
- Juvenile Spondyloarthropathy Syndromes
– family of disorders characterized
by arthritis in the spine, sacroiliac
and other large joints, and eye inflammation.
Occurs more often in boys than girls.
Rheumatic diseases can range from being
very localized and mild to systemic and
potentially life threatening. Because
of the complex nature of the trajectories
of pediatric rheumatic disease, it is
crucial that a child suspected of having
one of these illnesses visit a pediatric
rheumatologist early in the illness to
either establish or confirm the diagnosis,
and to continue to be monitored throughout
the duration of the illness to ensure
proper use of pharmacotherapies as well
as adjunctive therapies. The involvement
of a pediatric rheumatologist also enhances
access to novel therapies and therapies
available only through clinical trials.
In addition, a child with a rheumatic
disease may require the care of a team
of physicians and other providers to ensure
that all physical and emotional symptoms
are being addressed.
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