This document provides information about Idiopathic Thrombocytopenic Purpura (ITP), including:
- ITP is a blood disorder characterized by a decreased number of platelets, which can cause easy bruising and bleeding.
- There are two main forms - acute (seen in children and resolves in <6 months) and chronic (onset at any age and lasts >6 months).
- The cause is unknown in most cases but involves antibodies destroying platelets. Diagnosis involves ruling out other causes through testing.
- Treatment options depend on severity but may include steroids, IVIg, splenectomy, thrombopoietin receptor agonists, and experimental agents.
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idiopathic thrombocytopinic purpura
1. Idiopathic
Thrombocytopenic Purpura
(ITP)
Dr yogendra vijay
RESIDENT DOCTOR ,BLOOD TRANSEFUSION AND IMUNOHAEMATOLOGY
SMS MEDICAL COLLAGE ,JAIPUR RAJASTHAN
(druogendravijay23@gmail.com)
3. Idiopathic thrombocytopenic purpura is a blood
disorder characterized by an abnormal decrease
in the number of platelets in the blood. can
result in easy bruising, bleeding gums and internal
bleeding.
"Idiopathic" means the cause is unknown.
"Thrombocytopenia" means a decreased number
of platelets in the blood.
"Purpura" refers to the purple discoloring of the
skin, as with a bruise.
4. There are two forms of ITP:
Acute thrombocytopenic purpura — This is most commonly seen in
young children (2 to 6 years old). The symptoms may follow a viral
illness, such as chickenpox. Acute ITP usually has a very sudden onset
and the symptoms usually disappear in less than six months (often
within a few weeks). The disorder usually does not recur. Acute ITP is
the most common form of the disorder.
Chronic thrombocytopenic purpura — The onset of the disorder can
happen at any age, and the symptoms can last a minimum of six months
to several years. Adults have this form more often than children, but it
does affect adolescents. Chronic ITP can recur often and requires
continual follow-up care with a blood specialist .
5. pathophysiology
In approximately 60 percent of cases, antibodies against platelets can be detected.
Most often these are membrane glycoproteins IIb-IIIa or Ib-IX, and are of the (IgG)
type.
The coating of platelets with IgG renders them susceptible
to opsonization and phagocytosis by splenic macrophages, as well by Kupffer cells in
the liver
. The IgG autoantibodies are also thought to damage megakaryocytes, the precursor
cells to platelets,
Recent research now indicates that impaired production of
the hormone thrombopoietin, which is the stimulant for platelet production, may be a
contributing factor to the reduction in circulating platelets.
The stimulus for auto-antibody production in ITP is probably abnormal T
cell activity. Preliminary findings suggest that these T cells can be influenced by drugs
that target B cells, such as rituximab.
6.
7. In most cases, the cause of ITP is unknown and It is not
contagious.
Often, the child may have had a virus or viral
infection about three weeks before developing ITP. It
is believed that the body, when making antibodies
against a virus, "accidentally" also made an antibody
that can stick to the platelet cells. The body
recognizes any cells with antibodies as foreign cells
and destroys them. That is why ITP is also referred to
as immune thrombocytopenic purpura.
8. The bone marrow responds to the low number of platelets and
produces many more to send out to the body. in the bone marrow
many young platelets that have been produced. However, the blood test
results of the circulating blood would show a very low number of
platelets.
The body is producing the cells normally, but the body is also
destroying them. In most cases, other blood tests are normal except for
the low number of platelets. ITP platelets usually survive only a few
hours, in comparison to normal platelets which have a lifespan of 7 to
10 days.
Platelets are essential for the formation of a blood clot. Blood clots
consist of a mass of fibers and blood cells. Platelets travel to a damaged
area and stick together to form a plug, whenever a person is cut, for
example. If there are not enough platelets, a clot cannot be formed,
resulting in more bleeding.
9. Signs and symptoms
Normal platelet count is in the range of 150,000 to 450,000. In a child with ITP, the platelet
count is generally less than 100,000. By the time significant bleeding occurs, the child may
have a platelet count of less than 10,000. The lower the platelet count, the greater the risk
of bleeding.
Because platelets help stop bleeding, the symptoms of ITP are related to increased
bleeding.
Purpura - the purple color of the skin after blood has "leaked" under it. A bruise is blood
under the skin. Children with ITP may have large bruises from no known trauma. Bruises
can appear at the joints of elbows and knees just from movement.
Petechia - tiny red dots under the skin that are a result of very small bleeds.
Nose bleeds
Bleeding in the mouth and/or in and around the gums
Blood in the vomit, urine or stool
Bleeding in the head - this is the most dangerous symptom of ITP. Any head trauma that
occurs when there are not enough platelets to stop the bleeding can be life threatening.
10. Testing and diagnosis
The diagnosis of ITP is a process of exclusion.
First, it has to be determined that there are no blood abnormalities other than a low
platelet count, and no physical signs other than bleeding. Then, secondary causes (5–
10 percent of suspected ITP cases) should be excluded.
secondary causes include leukemia,
medications (e.g., quinine,heparin),
lupus erythematosus,
cirrhosis,
HIV, hepatitis C, congenital causes, antiphospholipid syndrome, von Willebrand
factor deficiency,
Despite the destruction of platelets by splenic macrophages, the spleen is normally not
enlarged.
In fact, an enlarged spleen should lead to a search for other possible causes for the
thrombocytopenia.
Bleeding time is usually prolonged in ITP patients. a normal bleeding time does not
exclude a platelet disorder.
11. Bone marrow examination may be performed on patients over the age
of 60 and those who do not respond to treatment, or when the diagnosis
is in doubt.
On examination of the marrow, an increase in the production of
megakaryocytes may be observed and may help in establishing a
diagnosis
A complete blood count (CBC), which measures the size, number, and
maturity of different blood cells
Additional blood and urine tests, which measure bleeding time and
detect possible infections
Careful review of the child's medications
A bone marrow aspiration may be performed to look at child's
production of platelets and to rule out any abnormal cells your child's
bone marrow could be producing that could lower platelet counts.
12. Treatment-
Not all children with ITP require treatment. Many
children spontaneously recover in about 2 to 4 day
Steroids, which help prevent bleeding by decreasing
the rate of platelet destruction. Steroids, if effective,
will result in an increase in platelet counts seen
within two to three weeks.
Initial treatment usually consists of the administration
of corticosteroids,
in urgent situations, infusions of
dexamethasone or methylprednisolone may be used,
while oral prednisone or prednisolone may suffice in
less severe cases
13. Anti-D
Another option, suitable for Rh-positive, non-splenectomized patients is
intravenous administration of Rho(D) immune globulin [Human; Anti-D].
The mechanism of action of anti-D is not fully understood. However, following
administration, anti-D-coated red blood cell complexes saturate Fcγ receptor sites
on macrophages, resulting in preferential destruction of red blood cells (RBCs),
therefore sparing antibody-coated platelets.
Steroid-sparing agents
Immunosuppresants such as mycophenolate mofetil and azathioprine
vincristine, a chemotherapy agent,and vinca alkaloid, has significant side-effects
and To be used with caution, especially in children.
Intravenous immunoglobulin (IVIg) may be infused in some cases. it is costly and
produces improvement that generally lasts less than a month.
14. Thrombopoietin receptor agonists
- are pharmaceutical agents that stimulate platelet production in the bone
marrow. Two such products are currently available:
•Romiplostim (trade name Nplate) is a thrombopoiesis stimulating Fc-peptide
fusion protein that is administered by subcutaneous injection.
• romiplostim is effective in treating chronic ITP, especially in relapsed
post-splenectomy patients.
•Eltrombopag (trade name Promacta ) is an orally-administered agent with
an effect similar to that of romiplostim. It too has been demonstrated to
increase platelet counts and decrease bleeding in a dose-dependent
manner.
Side effects of thrombopoietin receptor agonists include headache, joint
or muscle pain, dizziness, nausea or vomiting, and an increased risk of
blood clots.
15. Surgery
Splenectomy may be considered, as platelets which have been bound by
antibodies are taken up by macrophages in the spleen .
The procedure is potentially risky in ITP cases due to the increased
possibility of significant bleeding during surgery.
Platelet transfusion
Platelet transfusion alone is normally not recommended except in an
emergency, and is usually unsuccessful in producing a long-term platelet
count increase. This is because the underlying autoimmune mechanism
that is destroying the patient's platelets will also destroy donor platelets.
H. pylori eradication
In adults, particularly those living in areas with a high prevalence ,
identification and treatment of this infection has been shown to improve
platelet counts in a third of patients.
16. Experimental and novel agents
•Dapsone is an anti-infective sulfone drug. In recent
years, Dapsone has also proved helpful in treating
lupus, rheumatoid arthritis and used as second-line
treatment for ITP. The exact mechanism by which
Dapsone assists in ITP is unclear.
•The off-label use of rituximab, a chimeric monoclonal
antibody against the B cell surface antigen CD20, has
been shown in preliminary studies to be an effective
alternative to splenectomy in some patients.
•Promising results have been reported with kinase
inhibitor tamatinib fosdium