idiopathic thrombocytopenic purpura (redirected from ITP clinical features Acute Chronic)

Idiopathic Thrombocytopenic Purpura 

Definition

Idiopathic thrombocytopenic purpura, or ITP, is a bleeding disorder caused by an abnormally low level of platelets in the patient's blood. Platelets are small plate-shaped bodies in the blood that combine to form a plug when a blood vessel is injured. The platelet plug then binds certain proteins in the blood to form a clot that stops bleeding. ITP's name describes its cause and two symptoms. Idiopathic means that the disorder has no apparent cause. ITP is now often called immune thrombocytopenic purpura rather than idiopathic because of recent findings that ITP patients have autoimmune antibodies in their blood. Thrombocytopenia is another word for a decreased number of blood platelets. Purpura refers to a purplish or reddish-brown skin rash caused by the leakage of blood from broken capillaries into the skin. Other names for ITP include purpura hemorrhagica and essential thrombocytopenia.

Description

ITP may be either acute or chronic. The acute form is most common in children between the ages of two and six years; the chronic form is most common in adult females between 20 and 40. Between 10% and 20% of children with ITP have the chronic form. ITP does not appear to be related to race, lifestyle, climate, or environmental factors.

ITP is a disorder that affects the overall number of blood platelets rather than their function. The normal platelet level in adults is between 150,000 and 450,000/mm³. Platelet counts below 50,000 mm³ increase the risk of dangerous bleeding from trauma; counts below 20,000/mm³ increase the risk of spontaneous bleeding.

Causes and symptoms

In adults, ITP is considered an autoimmune disorder, which means that the body produces antibodies that damage some of its own products—in this case, blood platelets. Some adults with chronic ITP also have other immune system disorders, such as systemic lupus erythematosus (SLE). In children, ITP is usually triggered by a virus infection, most often rubella, chickenpox, measles, cytomegalovirus, or Epstein-Barr virus. It usually begins about two or three weeks after the infection.

Acute itp

Acute ITP is characterized by bleeding into the skin or from the nose, mouth, digestive tract, or urinary tract. The onset is usually sudden. Bleeding into the skin takes the form of purpura or petechiae. Purpura is a purplish or reddish-brown rash or discoloration of the skin; petechiae are small round pinpoint hemorrhages. Both are caused by the leakage of blood from tiny capillaries under the skin surface. In addition to purpura and petechiae, the patient may notice that he or she bruises more easily than usual. In extreme cases, patients with ITP may bleed into the lungs, brain, or other vital organs.

Chronic itp

Chronic ITP has a gradual onset and may have minimal or no external symptoms. The low platelet count may be discovered in the course of a routine blood test. Most patients with chronic ITP, however, will consult their primary care doctor because of the purpuric skin rash, nosebleeds, or bleeding from the digestive or urinary tract. Women sometimes go to their gynecologist for unusually heavy or lengthy menstrual periods.

The risk factors for the development of chronic ITP include:

• female sex
• age over 10 years at onset of symptoms
• slow onset of bruising
• presence of other autoantibodies in the blood

Diagnosis

ITP is usually considered a diagnosis of exclusion, which means that the doctor arrives at the diagnosis by a process of ruling out other possible causes. If the patient belongs to one or more of the risk groups for chronic ITP, the doctor may order a blood test for autoantibodies in the blood early in the diagnostic process.

Physical examination

If the doctor suspects ITP, he or she will examine the patient's skin for bruises, purpuric areas, or petechiae. If the patient has had nosebleeds or bleeding from the mouth or other parts of the body, the doctor will examine these areas for other possible causes of bleeding.

Patients with ITP usually look and feel healthy except for the bleeding.

The most important features that the doctor will be looking for during the physical examination are the condition of the patient's spleen and the presence of fever. Patients with ITP do not have fever, whereas patients with lupus and some other types of thrombocytopenia are usually feverish. The doctor will have the patient lie flat on the examining table in order to feel the size of the spleen. If the spleen is noticeably enlarged, ITP is not absolutely ruled out but is a less likely diagnosis.

Laboratory testing

The doctor will order a complete blood count (CBC), a test of clotting time, a bone marrow test, and a test for antiplatelet antibodies if it is available in the hospital laboratory. Patients with ITP usually have platelet counts below 20,000/mm³ and prolonged bleeding time. The size and appearance of the platelets may be abnormal. The red blood cell count (RBC) and white blood cell count (WBC) are usually normal, although about 10% of patients with ITP are also anemic. The blood marrow test yields normal results. Detection of antiplatelet antibodies in the blood is considered to confirm the diagnosis of ITP.

Treatment

General care and monitoring

There is no specific treatment for ITP. In most cases, the disorder will resolve without medications or surgery within two to six weeks. Nosebleeds can be treated with ice packs when necessary.

General care includes explaining ITP to the patient and advising him or her to watch for bruising, petechiae, or other signs of recurrence. Children should be discouraged from rough contact sports or other activities that increase the risk of trauma. Patients are also advised to avoid using aspirin or ibuprofen (Advil, Motrin) as pain relievers because these drugs lengthen the clotting time of blood.

Emergency treatment

Patients with acute ITP who are losing large amounts of blood or bleeding into their central nervous system require emergency treatment. This includes transfusions of platelets, intravenous immunoglobulins, or prednisone. Prednisone is a steroid medication that decreases the effects of antibody on platelets and eventually lowers antibody production. If the patient has a history of ITP that has not responded to prednisone or immunoglobulins, the surgeon may remove the patient's spleen. This operation is called a splenectomy. The reason for removing the spleen when ITP does not respond to other forms of treatment is that the spleen sometimes keeps platelets out of the general blood circulation.

Medications and transfusions

Patients with chronic ITP can be treated with prednisone, immune globulin, or large doses of intravenous gamma globulin. Although 90% of patients respond to immunoglobulin treatment, it is very expensive. About 80% of patients respond to prednisone therapy. Platelet transfusions are not recommended for routine treatment of ITP. If the patient's platelet level does not improve within one to four months, or requires high doses of prednisone, the doctor may recommend splenectomy. All medications for ITP are given either orally or intravenously; intramuscular injection is avoided because of the possibility of causing bleeding into the skin.

Surgery

Between 80% and 85% of adults with ITP have a remission of the disorder after the spleen is removed. Splenectomy is usually avoided in children younger than five years because of the increased risk of a severe infection after the operation. In older children, however, splenectomy is recommended if the child has been treated for 12 months without improvement; if the ITP is very severe or the patient is getting worse; if the patient begins to bleed into the head or brain; and if the patient is an adolescent female with extremely heavy periods.

Prognosis

The prognosis for recovery from acute ITP is good; 80% of patients recover without special treatment. The prognosis for chronic ITP is also good; most patients experience long-term remissions. In rare instances, however, ITP can cause life-threatening hemorrhage or bleeding into the central nervous system.

Resources

Books

Linker, Charles A. "Blood." In Current Medical Diagnosis and Treatment, 1998, edited by Stephen McPhee, et al., 37th ed. Stamford: Appleton & Lange, 1997.

Key terms

Autoimmune disorder — A disorder in which the patient's immune system produces antibodies that destroy some of the body's own products. ITP in adults is thought to be an autoimmune disorder.

Idiopathic — Of unknown cause. Idiopathic refers to a disease that is not preceded or caused by any known dysfunction or disorder in the body.

Petechiae — Small pinpoint hemorrhages in skin or mucous membranes caused by the rupture of capillaries.

Platelet — A blood component that helps to prevent blood from leaking from broken blood vessels. ITP is a bleeding disorder caused by an abnormally low level of platelets in the blood.

Prednisone — A corticosteroid medication that is used to treat ITP. Prednisone works by decreasing the effects of antibody on blood platelets. Longterm treatment with prednisone is thought to decrease antibody production.

Purpura — A skin discoloration of purplish or brownish red spots caused by bleeding from broken capillaries.

Splenectomy — Surgical removal of the spleen.

Thrombocytopenia — An abnormal decline in the number of platelets in the blood.

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purpura /pur·pu·ra/ (pur´pu-rah)

1. a small hemorrhage in the skin, mucous membrane, or serosal surface.

2. a group of disorders characterized by the presence of purpuric lesions, ecchymoses, and a tendency to bruise easily.purpu´ric

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allergic purpura , anaphylactoid purpura Henoch-Schönlein p.

purpura annula´ris telangiecto´des  a rare form in which punctate erythematous lesions coalesce to form an annular or serpiginous pattern.

fibrinolytic purpura  purpura associated with increased fibrinolytic activity of the blood.

purpura ful´minans  nonthrombocytopenic purpura seen mainly in children, usually after an infectious disease, marked by fever, shock, anemia, and sudden, rapidly spreading symmetrical skin hemorrhages of the lower limbs, often associated with extensive intravascular thromboses and gangrene.

purpura hemorrha´gica  idiopathic thrombocytopenic p.

Henoch's purpura  Henoch-Schönlein purpura in which abdominal symptoms predominate.

Henoch-Schönlein purpura  nonthrombocytopenic purpura of unknown cause, usually in children; associated with symptoms such as urticaria, erythema, arthropathy and arthritis, gastrointestinal disorder, and renal involvement.

idiopathic thrombocytopenic purpura  thrombocytopenic purpura not directly associated with a systemic disease, although often following a systemic infection; believed to be due to an IgG immunoglobulin that acts as an antibody against platelets.

malignant purpura  meningococcal meningitis.

nonthrombocytopenic purpura  purpura without any decrease in the platelet count of the blood.

Schönlein purpura  Henoch-Schönlein purpura with articular symptoms and without gastrointestinal symptoms.

Schönlein-Henoch purpura  Henoch-Schönlein p.

purpura seni´lis  dark purplish red ecchymoses occurring on the forearms and backs of the hands in the elderly.

thrombocytopenic purpura  any form in which the platelet count is decreased, occurring as a primary disease (idiopathic thrombocytopenic p.) or as a consequence of a primary hematologic disorder (secondary thrombocytopenic p.) .

thrombotic thrombocytopenic purpura  a form of thrombotic microangiopathy marked by thrombocytopenia, hemolytic anemia, neurological manifestations, azotemia, fever, and thromboses in terminal arterioles and capillaries.

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idiopathic thrombocytopenic purpura

n. Abbr. ITP

A systemic illness of unknown cause, characterized by extensive ecchymoses and hemorrhages from mucous membranes, deficiencies in the numbers of platelets, anemia, and extreme weakness. Also called immune thrombocytopenic purpura, purpura hemorrhagica, thrombocytopenic purpura, Werlhof's disease.

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idiopathic thrombocytopenic purpura (ITP),

a deficiency of platelets that results in bleeding into the skin and other organs. Acute ITP is a disease of children that may follow a viral infection, lasts a few weeks to a few months, and usually has no residual effects. Chronic ITP is more common in adolescents and adults, begins more insidiously, and lasts longer. Antibodies to platelets are found in patients with ITP. The condition may be transmitted to the fetus if the mother is affected. Treatment includes hemophoresis, corticosteroids, therapeutic plasmapheresis, and splenectomy. See also thrombocytopenia, thrombocytopenic purpura.

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purpura (pur´pyoor),

n an extravasation of blood into the tissues, resulting in blue to black lesions of the skin or mucosa (petechiae and ecchymoses).

Purpura.

purpura, allergic,

n (anaphylactoid purpura) a thrombocytopenic or nonthrombocytopenic purpura related to an allergic reaction. Manifestations include the common symptoms of allergy.

purpura, anaphylactoid

n See purpura, allergic.

purpura, essential,

n See purpura, thrombocytopenic, idiopathic.

purpura hemorrhagica

n See purpura, thrombocytopenic and purpura, thrombocytopenic, idiopathic.

purpura, idiopathic thrombocytopenic,

n (essential purpura, land scurvy, primary purpura, purpura hemorrhagica) a type of unknown cause.

purpura, nonthrombocytopenic,

n a type related to increased capillary permeability. Included are allergic purpuras and those resulting from vitamin C deficiency, bacterial toxins (scarlet fever, typhoid), drug intoxications, and metabolic toxins (nephritis, liver disease).

purpura, primary,

n See purpura, thrombocytopenic, idiopathic.

purpura, secondary,

n See purpura, thrombocytopenic, symptomatic.

purpura, symptomatic thrombocytopenic,

n (secondary purpura) a type resulting from the effects of chemical, physical, vegetable, or animal agents or infections or related blood disorders.

purpura, thrombocytopathic

n a type associated with qualitative abnormalities of the platelets.

purpura, thrombocytopenic

n (essential thrombopenia, pseudohemophilia, hemorrhagica, Werlhof's disease) a type characterized by severe ecchymoses and petechiae associated with marked reduction in the numbers of blood platelets. There is prolonged bleeding time and poor clot retraction, but the coagulation and prothrombin times are normal. Hemorrhage may occur spontaneously from any area of the oral mucosa. This disease may be acute and fatal, whereas in other instances it may run a chronic course with intermittent attacks.

purpura, thrombotic thrombocytopenic,

n a febrile disease of unknown cause characterized by hemolytic anemia, neurologic symptoms, hemorrhage into the skin and mucous membranes, icterus, hepatosplenomegaly, low platelet count, and platelet thrombi occluding capillaries and arterioles.

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idiopathic thrombocytopenic purpura

Werlhof's disease Hematology A diagnosis of exclusion characterized by thrombocytopenia without known exogenous etiologic factors, or conditions known to be associated with 'secondary' thrombocytopenia; in most Pts, ITP is attributed to immune-mediated accelerated platelet destruction; acute ITP is more common in children, causing a self-limited wave of ecchymotic hemorrhage 2º to viral infection or vaccination; chronic ITP is more common in adults and often is autoimmune with mucocutaneous, CNS, cardiac and renal hemorrhage–and potentially, infarction, bruisability, transient thrombocytopenia–with normal or ↑ megakaryocytes in BM;²⁄₃ of cases have IgG antiplatelet antibodies and hemolysis in splenic sinusoids Clinical ♀:♂ ratio 3:1, microangiopathic hemolytic anemia, fever, transient neurologic defects, renal failure, microthrombolic 'showers' to brain, heart, lungs, kidneys, adrenal glands, spleen and liver DiffDx Microthrombi of TTP of young ♀, microangiopathic hemolytic anemia, neurologic defects, renal failure Treatment Efficacy of most therapies used in ITP is uncertain, especially given that spontaneous remission occurs, the small populations studied, and the wide difference in Pt populations; modalities include splenectomy–up to 75% markedly improve with splenectomy, prednisone, IV gamma globulin, immunoadsorption apheresis on staphylococcal protein A columns, plasmapheresis; low-dose corticosteroids or to pulsed high-dose dexamethasone, combination chemotherapy–eg, azathioprine, cochicine, cyclosporine, danazol, vincristine

ITP clinical features   Acute Chronic

Peak age Children, age 2-6 Adults, age 20-40

Sex (♀:♂ratio) 1:1 3:1

History, recent infection Common Rare

Onset  Abrupt Insidious

Hemorrhagic bullae-oral Present if severe Rare

Eosinophilia, lymphocytosis Common Rare

Platelet count < 20 x 10⁹/L 30-80 x 10⁹/L

Duration 2-6 weeks Months, years

Spontaneous remission Common, ± 80% Rare, ± 20%  

After TC Bithell, in GR Lee, et al Eds, Wintrobe's Clinical Hematology, 9th ed, Lea & Febiger, Philadelphia, 1993