Idiopathic (Autoimmune) Thrombocytopenic Purpura
Julie Adkins, Jill C. Cash, Beverly R. Byram, Cheryl A. Glass, Kristin Ownby, and Pat Obulaney
Definition
A.Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder in which an immunoglobulin G (IgG) autoantibody is formed that binds to platelets. Platelets help your blood clot by clumping together to plug small holes in damaged blood vessels. The platelet count is less than 150,000 mm³.
Incidence
A.Acute ITP commonly occurs in childhood, frequently precipitated by a viral infection. Peak age of incidence is between 20 and 50 years. There is a 2:1 female-to-male predominance; however the prevalence in men and women is equal in the elderly 65 or older. The adult form is usually a chronic disease (>6 months) and it seldom follows a viral infection.
Pathogenesis
A.ITP is due to production of antiplatelet antibodies that lead to peripheral destruction and sequestration of platelets. It is not clear which antigen on the platelet surface is involved. Platelets are not destroyed by direct lysis even if the antiplatelet antibody binds complement. Destruction takes place in the spleen, where splenic macrophages with Fc receptors bind to antibody-coated platelets.
Predisposing Factors
A.Infections including hepatitis C.
B.Chronic alcoholism.
C.Sepsis.
D.AIDS.
E.Immune disorders, such as systemic lupus erythematosus (SLE).
F.Drug use.
G.Chronic lymphocytic leukemia (CLL).
H.Pregnancy.
Common Complaints
A.Purple spots and bruises on skin.
B.Nosebleeds.
C.Mouth and gums bleeding.
Other Signs and Symptoms
A.Purpura, petechiae, and hemorrhagic bullae in the mouth.
B.Tendency to bleed easily—easy bruising.
C.Menorrhagia—abnormal heavy menstruation.
D.No systemic illness: The patient feels well and is not febrile.
Subjective Data
A.Determine when the patient or caregiver first noticed symptoms; note if the symptoms have changed or progressed.
B.Rule out pregnancy as cause of nosebleeds.
C.Ask if the patient is feeling well except for the bleeding or bruising.
D.Determine if the patient has a fever.
E.Obtain medication history for over-the-counter (OTC) and prescribed medications.
F.Determine the patient’s history of immune disorders, recent infections, alcoholism, and pregnancy.
G.Establish usual weight and any recent weight loss.
Physical Examination
A.Check temperature, pulse, respirations, blood pressure, and weight.
B.Inspect.
1.Observe general appearance.
2.Conduct dermal exam for purpura and petechiae.
3.Conduct eye exam; check sclera for hemorrhages.
4.Examine the mouth for dental carries and poor hygiene, mouth petechiae, and hemorrhagic bullae.
C.Palpate: Normally, the spleen should not be palpable.
1.Palpate the abdomen, liver, and spleen.
2.Palpate the cervical, axillary, and groin lymph nodes for adenopathy.
D.Percuss: Percuss the abdomen, liver, and spleen.
E.Auscultate:
1.Auscultate the heart and lungs.
2.Auscultate the abdomen for bowel sounds and bruits.
Diagnostic Tests
A.Platelet count: The major concern during the initial phase is risk of cerebral hemorrhage when platelet count is less than 5,000 platelets/fiL.
B.IgG: Increased levels of IgG appear on the platelet count in the presence of thrombocytopenia.
C.Complete blood count (CBC) with differential and peripheral smear: Peripheral smear shows normal white blood cells (WBCs) and red blood cells (RBCs), platelets low in count with large size.
D.Bleeding time is prolonged.
E.Tests for HIV and hepatitis C.
F.Referral for bone marrow aspiration if not responding to therapy. Bone marrow may appear normal or have increased megakaryocytes (early form of platelets) with thrombocytopenia.
Differential Diagnoses
Thrombocytopenia may be produced in two ways: By abnormal bone marrow function or by peripheral destruction of platelets.
A.Abnormal bone marrow function:
1.Aplastic anemia.
2.Hematologic malignancies.
3.Myelodysplasia: This can only be ruled out by examining the bone marrow.
4.Megaloblastic anemia.
5.Chronic alcoholism.
B.Non–bone marrow disorders:
1.Immune disorders:
a.ITP.
b.Drug induced from medications being taken.
c.Secondary to CLL and SLE.
d.Posttransfusion purpura.
2.Hypersplenism resulting from liver disease.
3.Disseminated intravascular coagulation (DIC).
4.Thrombotic thrombocytopenic purpura.
5.Sepsis.
6.Hemangiomas.
7.Viral infection, AIDS.
8.Pregnancy.
9.Hypothyroidism.
Plan
A.General interventions:
1.Comanage the patient with a physician for medication therapy.
B.Patient teaching:
1.Instruct the patient to avoid trauma; advise no contact sports.
2.Instruct the patient to avoid salicylates or nonsteroidal anti-inflammatory drugs (NSAIDs), which impair platelet function.
3.Prednisone therapy benefits:
a.Prednisone increases platelet count by increasing platelet production.
b.Long-term therapy may decrease antibody production.
c.Bleeding often diminishes 1 day after beginning prednisone.
d.Platelet count usually begins to rise within a week; responses are almost always seen within 3 weeks.
e.About 80% of patients respond, and the platelet count usually returns to normal.
C.Medical or surgical management:
1.Splenectomy is considered 6 to 12 months after initial diagnosis and when medical management has failed.
2.Two to 10 weeks prior to the splenectomy, patients need to be immunized with pneumococcal conjugate vaccine (PCV13), haemophilus influenzae type B, meningococcal conjugate, and meningococcal B vaccines. Patient will receive pneumococcal polysaccharide vaccine (PPSV23) 8 weeks after the splenectomy and a second dose 5 years later. Annual influenza immunization is recommended.
D.Pharmaceutical therapy:
1.Initial treatment:
a.Prednisone 1 to 2 mg/kg/d.
b.High-dose therapy should be continued until the platelet count is normal, and the dose should then be gradually tapered.
2.In most patients, thrombocytopenia recurs if prednisone is completely withdrawn.
3.High-dose therapy should not be continued indefinitely in an attempt to avoid surgery.
4.Alternative drug therapy:
a.High-dose intravenous immunoglobulin (IVIg) 400 mg/kg/d for 3 to 5 days is highly effective in rapidly raising the platelet count:
i.This treatment is expensive, costing approximately $5,000.
ii.The beneficial effect lasts only 1 to 2 weeks.
iii.This therapy should be reserved for emergency situations such as preparing a severely thrombocytopenic patient for surgery.
5.Rituximab may be considered for adult patients who failed corticosteroids and IVIg and are at risk of bleeding.
6.Thrombopoietin receptor agonists are recommended for patients at risk of bleeding who relapse after splenectomy and have failed other therapies
7.Platelet transfusions are an option rarely used.
8.Avoid aspirin, NSAIDs, and warfarin, which interfere with platelet function and blood clotting. Be aware if the patient is also taking any new selective inhibitors of factor Xa such as Xarelto, Pradaxa, or Eliquis, and so on.
Exogenous platelets survive no better than the patient’s own platelets. In many cases, platelets survive less than a few hours. This therapy is reserved for cases of life-threatening bleeding in which enhanced hemostasis for even an hour may be of benefit.
Follow-Up
A.The patient must be monitored very closely. Platelet counts should be drawn daily to weekly; frequency depends on the severity and course.
B.Prognosis for acute ITP: 80% respond and fully recover within 2 months; 15% to 20% progress to chronic ITP.
C.Prognosis for chronic ITP: 10% to 20% recover fully; remainder continue to have low platelet counts and may see a remission or relapse over time.
D.The principal cause of death from ITP is intracranial hemorrhage.
Consultation/Referral
A.After diagnosis, refer the patient to a hematologist.
Individual Considerations
A.Pregnancy:
1.Rule out hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome, infection, and DIC as causes of thrombocytopenia.
2.There is an increased incidence of spontaneous abortions and hemorrhage at the time of delivery from genital tract injury.
3.Antepartum management: Conduct fetal blood sampling and testing when the mother has a known history of ITP.
4.Intrapartum management:
a.Avoid fetal hypoxia, which can decrease the fetal platelet count.
b.Avoid prolonged labor.
c.Conduct continuous fetal monitoring.
d.Epidural anesthesia may be used if the platelet count is at least 100,000 cells/mm3.
5.Postpartum management: Breastfeeding is not recommended because of the possible transmission of antiplatelet antibodies through breast milk.
B.Geriatrics:
1.ITP is uncommon in this population; there is usually another cause for low platelets
2.Avoid medications that impede platelet function.
3.Research posited that geriatrics with ITP respond well to low-dose prednisone as first-line treatment.
4.Studies suggest that once geriatrics are diagnosed with ITP, they experience approximately two bleeding-related events a year. These statistics support the importance of examining bleeding and use of ITP therapy in the elderly population suffering with ITP.