In this lecture, we will discuss
Juvenile Idiopathic Arthritis.
Here's a classic case.
An 11-year-old child is presenting to
you after several rounds of antibiotics
with a complaint of long standing pain and
swelling of the fingers, wrists and ankles.
What's the most
In this case, it's probably
Juvenile Idiopathic Arthritis
or JIA for short.
JIA causes pain and swelling in the joints
that typically lasts longer than six weeks.
It's an autoimmune disease that
primarily affects children,
and is typical onset is
before 16 years of age.
There are three different major types of
JIA and a few smaller less common types.
The major types that are
likely to show up on our exam
are Oligoarticular JIA which usually
involves fewer than six joints,
Polyarticular JIA which
is multiple joints,
and Systemic JIA which may involve
a wide variety of systemic symptoms.
There are other types of JIA
too that are less common.
Enthesitis-associated JIA is a
variety of JIA that causes enthesitis
which is an inflammation of the
insertion of around the joint.
Psoriatic JIA is associated
with psoriasis of the skin.
And Undifferentiated JIA may be a
variety of different types of JIA
that don't really fit into one
category in that particular patient.
So, JIA characteristics do usually
involve joint inflammation.
And the synovium is the target
for that autoinflammatory process.
It results in a proliferation of synovial
tissue and increased joint fluid.
You may see increased blood flow,
swelling and inflammatory cells
if you were to tap that joint.
The progression of symptoms is generally
it starts off with a persistent synovitis
which then results
in joint destruction,
which can cause long term bone,
tendon, ligament problems.
So of the three major types,
they tend to present slightly differently.
Let's start with
This is about half of cases, females
are more commonly affected than males.
And it's really in
the 2-3 year range.
It would be very rare for this disease
to present after 10 years of age.
Polyarticular JIA is
about a third of cases.
Again, females are more
affected than males.
And there seem to be two periods
of time when it shows up the most
between 2 and 5,
and between 10 and 14.
Systemic JIA is the minority
of cases only about 1 in 10.
And there's no predominance
for either gender.
It can happen at any age,
really under 17 years of age.
So let's drill down on the
three major types of JIA.
Oligoarticular JIA is
usually less than five
or at least less than six
joints that are affected.
Those joints include
medium and large joints,
the disease tends to be asymmetric
and how it attacks the child.
It's rarely that
involves the hips,
and this tends to be a
There are usually no
These children are a febrile
and otherwise doing well.
But there are two groups.
If the child has ANA+,
they are more likely to have a
uveitis about 20% of the time.
The ANA- patients
are less likely to.
Polyarticular JIA usually
involves multiple joints.
It can involve any joint it wants to but
this disease is usually more symmetric.
So our initial case with
involvement of the hands, the feet,
the ankles would be classic
for a Polyarticular JIA.
It rarely involves the hips as well
and this is a destructive arthritis
It less frequently
Polyarticular JIA is
broken down into 0-
and 0+ Polyarticular
JIA depending on whether
the rheumatoid factor
is negative or positive.
0+ Polyarticular JIA,
an analogue of adult
is seen in less than 10%
of pediatric patients.
0- Polyarticular JIA,
an entity more
specific for childhood
appears with widespread large
and small joint involvement.
Systemic JIA may have
any joints or no joints.
If it involves joints,
it's often a destructive arthritis.
These patients usually come in
complaining of high fevers daily.
They may have an evanescent
and I'll show you a photo
of that in a minute.
They may have a hepatosplenomegaly,
lung or liver involvement.
These children have a
systemic autoimmune process.
Here's an example of how
children can be affected.
These are two sisters.
And this 4-year-old sister
is substantially affected
in terms of her ability to have
functioning joints long term.
This is the chronic destruction you
see in what is likely in this child.
Polyarticular JIA, it's symmetric,
it's involving multiple joints.
So when you're
diagnosing a patient,
you will want to hear a history
of joint pain and typically,
unless it's the systemic
variety that you're suspecting.
Oftentimes patients will have
morning stiffness or stiffness still
for after being still for a prolonged
period of time we call this gelling.
In other words, if a patient is
just sitting there for a while
and then gets up,
they have that stiffness again,
These patients often have limp, especially
when the lower extremities are involved.
About 25% of patients with JIA will have
no report of pain and only swelling,
and the massage
doesn't seem to help.
So here is that salmon-pink rash that
evanescent rash of systemic onset JIA.
I'll be honest,
I have not seen this rash in the patients
that I've seen
with systemic JIA.
It's not always there and it doesn't
always show up in any individual patient.