Now let's cover idiopathic
thrombocytopenia purpura or ITP.
ITP is a platelet disorder that occurs in people who
have an abnormally low number of platelets in the blood.
This is idiopathic, that means
we don't know the cause.
Thrombocytopenia which is the
decreased number of platelets,
And puprura, that's the discoloration
of the skin - it's purple, looks like a bruise.
In the United States, approximately 4 to
8 children per 100,000 under the age of 15
will have one of the two forms of ITP.
"Purpura" is a word of Latin origin meaning
purple and it denotes reddish purple lesions.
that are greater than 2 mm in size
caused by bleeding under the skin.
Here in the right, you'll see some petechiae
and those are smaller pinpoint hemorrhages,
those are usually less than 2 mm in size.
So this was first recognised by the ancient
Greeks and Romans, Hippocrates and Galen
ITP has acquired many different names throughout history and
through the study and understanding of the disease process.
There are two types, the first is
acute, this is the most common form.
We see this in pediatrics
usually ages 2 to 6.
This is usually after a viral
illness and it has a sudden onset.
It's gonna resolve in less than 6 months
and usually goes away within a few weeks.
It usually does not recur in these
patients, it's a one-time isolated incident.
That's in contrast to chronic ITP and this is less common,
this can happen at any age but it's more common in adults.
It's gonna last for greater than 6
months and that's what makes it chronic.
It's more common in females and it's going to recur
and require management by a specialist - a hematologist.
So let's compare and contrast here.
In acute ITP, the peak incidence we service
between 2 and 6 years old so we think of pediatrics.
It's not preferred male or
female, there's no sex predilection.
And the antecedent infection is usually viral.
These kids will usually have a virus or
a cold 1 to 3 weeks before this begins.
The onset of bleeding can be abrupt and the platelet
count is really low, it's less than 20,000 per microliter.
The eosinophils and the lymphocytes
in the white blood cells can be elevated
and this is common, this is
eosinophilia and lymphocytosis.
The duration, remember it lasts about 2 to 6 weeks,
it rarely last longer but it can last a few months.
And it will go away spontaneously
about 80% of the time.
That's in contrast to chronic ITP, remember
this is the adult population, 20 to 40 year olds.
It's more common in females than males, there's
usually no antecedent infection and it's insidious
which means it's not an abrupt bleeding,
it's a slow steady decline in the platelets.
The platelet counts are gonna
drop to between 30,000 and 80,000
and we rarely see changes with
the eosinophils and the lymphocytes.
This can last for months or years
because remember it's a chronic condition
and it usually does not
have spontaneous remission.
It is idiopathic in the absence of other causes of
thrombocytopenia such as medications, infections,
malignancies or other autoimmune disorders.
If you can explain by one of these causes why your
patient has thrombocytopenia, than they don't have ITP.
So we said most cases are unknown, it's
important to know this is not contagious,
you're not gonna spread this to another patient.
And a common cause that we talked about as a post-viral
setting usually three weeks after a viral illness.
So remember in the pediatric population,
it's benign and self limiting and it's rare.
We see this in 4 to 8 per 100,000 children per
Often a child will have a virus about 3 weeks
before developing ITP, this is the classic story
While making antibodies against their viral infection,
the body can also accidentally make antibodies
that are gonna stick to the platelets.
The body's gonna recognize these, mistakingly thinking
that they'r foreign cells and will begin to destroy them.
The bone marrow at the center of the long bones is
responsible for making the blood cells including the platelets.
the bone marrow's gonna respond to the low number of
platelets by trying to churn out even more platelets.
This is gonna result in an increased
number of young platelets in circulation.
A normal healthy platelet will live 7 to 10 days but in
the setting of ITP, they will only live for a few hours.
The rate of destruction is gonna
exceed the rate of production
and adequate number of useful platelets
are not available to form a blood clot.
So we see two processes going on in ITP.
The first is we have
increased platelet destruction.
These antibodies again are
gonna tag and mark the platelets
and that's gonna cause the cells of the
immune system to attack and destroy them.
The second process that's going on is
the body's not able to make enough platelets
to make up for those being destroyed.
ITP is gonna result in the increased platelet
destruction and the impaired platelet production.
Here we see the normal blood vessel up top,
the patient has a normal amount of red blood cells
and a normal amount of platelets.
Down in the setting of ITP, the patient's red blood cells
are normal but they have a decreased amount of platelets.