Idiopathic thrombocytopenic Purpura (ITP)

Sample for Idiopathic thrombocytopenic Purpura (ITP)

1. Plasma is needed.
2. Plasma is separated and frozen in a plastic tube.
3. Or collect the blood in acid citrate dextrose (ACD) solution.
4. Apply the pressure or do a pressure dressing to stop the bleeding.

Precautions for Idiopathic thrombocytopenic Purpura (ITP)

1. Apply the pressure to the site of the blood sample.
2. If bleeding occurs from the site, ask the patient to apply pressure.

Indications for Idiopathic thrombocytopenic Purpura (ITP)

1. This test is indicated when there are low platelet counts.
2. In the case of unresponsive to the treatment of low platelets.

Pathophysiology of Idiopathic thrombocytopenic Purpura (ITP)

1. Platelets are mainly involved in the clotting mechanism.
2. Antiplatelet antibodies are found in patients with idiopathic thrombocytopenic purpura (ITP), where the antigen is platelets.
3. Autoimmune (idiopathic) thrombocytopenic purpura may be divided into:
   1. Acute.
   2.  Chronic.
4. There is the immune-mediated destruction of the platelets.

5. The antibodies are usually directed against the HLA-antigen on the surface of platelets. Or maybe platelets-specific antigens (PLA1 and PLA2)

Immunologic thrombocytopenia:

1. Immunologic thrombocytopenia may be due to the following causes:

1. Idiopathic thrombocytopenic purpura (ITP):

1. This is an autoimmune phenomenon; platelets are destroyed in the spleen or reticuloendothelial system.
   1. Chronic idiopathic thrombocytopenia:
      1. This is more common in females aged 15 to 50 years.
      2. This is the most common cause without anemia and leucopenia.
      3. This is also associated with other diseases like systemic lupus erythematosus (SLE), HIV infection, chronic lymphocytic leukemia, Hodgkin’s disease, or autoimmune hemolytic anemia.
   2. Platelets associated with antibodies (Immunoglobulin IGg) are found in 90% of the cases.

2. Post-transfusion purpura:

1. This rare phenomenon is seen after a blood transfusion and may be seen within a few hours to a few days.
2. It is usually seen around the 10th day of the transfusion.
3. This will develop due to antibodies in the recipient developing against platelet antigen-1a (HPA-1a) absent from the patient’s own platelets on transfused platelets.
4. Treatment is by giving intravenous immunoglobulin, plasma exchange, or corticosteroids.

3. Maternal-fetal platelet incompatibility:

1. This usually occurs when the fetus has PLA1 and the mother lacks this antigen. Mothers develop antibodies, which can cross the placental barrier and give rise to neonatal thrombocytopenia.

Drug-induced thrombocytopenia.

• This is due to the hypersensitivity reaction to drugs. e.g., Cimetidine, analgesics like salicylate and acetaminophen, antibiotics (cephalosporin, penicillin, sulphonamide), quinidine drugs, oral hypoglycemic agents, heavy metal ( gold, organic arsenical), diuretics (chlorothiazide), digoxin, heparin, and propylthiouracil.

Other classifications of thrombocytopenia:

1. Increased platelets destruction:
   1. Primary immune mechanism:
   2. Idiopathic thrombocytopenic purpura (ITP).
      1. Post transfusional purpura.
      2. Neonatal isoimmune purpura.
      3. Drug-induced thrombocytopenia.
   3. Secondary immune mechanism:
      1. Lymphoproliferative disorder.
      2. Autoimmune disease SLE.
      3. Viral infections like infectious mononucleosis, HIV, and measles.
      4. Hemolytic uremic syndrome.
      5. Disseminated intravascular coagulopathy (DIC).
      6. Microangiopathic thrombocytopenia.
      7. Pregnancy-associated thrombocytopenia.
2. Abnormal platelets destruction:
   1. Splenomegaly leads to hypersplenism.
   2. Hemangiomas.
3. Decreased production of the platelets:
   1. Lymphomas.
   2. Leukemias.
   3. Metastatic carcinoma infiltration of the bone marrow.
   4. Myelofibrosis.
   5. Aplastic anemia.
   6. Pernicious anemia.
   7. Folic acid deficiency.

Symptoms of low platelets:

1. If there is a bruise or bleeding, it will take longer to stop.
2. Skin bruises easily.
3. In the female, there is heavy bleeding.
4. There are frequent nosebleeds.

Signs and symptoms of  Idiopathic thrombocytopenic purpura (ITP):

1. In the beginning, there are nonspecific symptoms.
2. It may develop ITP within 1 to 3 weeks of the viral infection in young children.
   1. The onset of symptoms is usually abrupt and usually counts as <20,000 /cmm.
   2. The disease is usually self-limiting, and spontaneous remission with or without therapy occurs in most cases.
3. In adults, this is seen between the ages of 20 to 50 years and is more common in females.
   1. There is no recent history of infection or drug therapy.
   2. Typically platelets <30,000/cmm, the patient may have a bleeding tendency.
   3. Typically patients will have mucosal bleeding.
   4. The primary hemostatic defect is seen as menorrhagia, epistaxis, bruises, or petechiae.

Signs and symptoms of Thrombotic thrombocytopenic purpura (TTP):

1. This rare and often fatal syndrome is associated with low platelet count (thrombocytopenia).
   1. Then patients develop weakness, malaise, fatigue, and fever.
   2. The patient may develop abdominal pain.
      1. The patient may have abdominal pain, pancreatitis, and gastrointestinal bleeding.
   3. These patients may have neurologic and renal dysfunction.
      1. There may be a mild headache; in some cases, patients may develop coma and seizures.
2. S/S severity is variable.
3. Fever is usually <38 °C.
4. The patient may develop proteinuria or hematuria, and these signs are mild.

Possible Complications of Idiopathic thrombocytopenic Purpura (ITP):

1. There is the possibility of bleeding.
2. There may be a bruise formation.
3. There is the possibility of infection.
4. Some patients may feel dizziness.

The normal level of platelets

Platelets

• Platelet antibody = Negative

Increased levels of Ab seen in:

1. Immunologic thrombocytopenic purpura( ITP)
2. Neonatal thrombocytopenia.
3. Posttransfusion purpura.
4. Drug-induced thrombocytopenia.
5. Systemic lupus erythematosus.

Treatment of Idiopathic thrombocytopenic Purpura (ITP)

1. The count above 50,000/cmm does not require treatment.
2. Steroids (corticosteroids)  are given in high doses.
   1. 80% of the patients respond and go into remission.
      1. Prednisolone 1 mg/kg/day is the initial dose in the adult.
      2. The dose is gradually reduced to lower doses after 10 to 14 days.
   2. Splenectomy is the second choice.
      1. This is advised in patients with a count <30,000/cmm after the steroids for three months.
      2. Or in patients on high doses of steroids to maintain a count above 30,000/cmm.
   3. Immunoglobulins are given intravenously in high doses, and there is a rapid increase in the platelet count.
      1. 400 mg/kg/day for 5 days or 1 gram/kg/day for 2 days.
   4. Immunosuppressant drugs like vincristine, cyclophosphamide, azathioprine, or cyclosporin alone or in combination.
   5. Platelets transfusion.
   6. Stem cell transplantation can be tried.

Critical value = <50,000/cmm or >one million /cmm.

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