IMMUNE THROMBOCYTOPENIA

Cathy Payne MSN, ACNP-BC Hematology/Oncology Nurse Practitioner

Ironwood Cancer and Research Centers

OBJECTIVES

• Define ITP • Terminology • Epidemiology • Mortality/Morbidity • Pathophysiology • Diagnosis • ASH guidelines/Management

Immune Thrombocytopenia

• ITP is an autoimmune-mediated hematologic disorder, in which the patients immune system produces antibodies directed against platelet antigens resulting in immune mediated platelet destruction and/or suppression of platelet production

• Cines, D.B., Blanchet, VS, (2002) Immune thrombocytopenia purpura.

PATHOPHYSIOLOGY

• reduced platelet lifespan due to antibody mediated destruction, as well as impaired platelet production

• specific IgG autoantibodies produced by the patient’s B cells most often are directed against

• platelet membrane glycoproteins like GPIIb/IIIa inciting events- viral infections and systemic conditions, malignancies

TERMINOLOGY

• Diagnostic platelet count <100,000 • Primary vs secondary • Duration • Severity • Refractory ITP • Response to treatment

EPIDEMIOLOGY

• 1 to 3 per 100,000 adults • Young women • Incidence increases with age with a slight male

predominance

MORBIDITY/MORTALITY

• Most patients will have good outcomes with infrequent hospital admissions and no excess mortality compared with the general population

• patients with persistent severe thrombocytopenia not responding to therapy within first 2 years have considerable M/M

• Bleeding/infections cause of death

DIAGNOSING ITP

• HISTORY• ethanol history • liver disease • drug history • bleeding/bruising • family history • risk factors for HIV or hepatitis C and or B symptoms • Symptoms of MDS • autoimmune disorders • recent viral infection • history of transfusions

PHYSICAL EXAM

• petechiae • purpura • conjunctival bleeding • retinal hemorrhages • lesions on mucosal membranes • enlarged liver or spleen • lymph nodes • sighs of sepsis, DIC or other severe systemic

abnormalities • pregnancy

COMPLETE BLOOD COUNT

• Isolated thrombocytopenia, plt count < 100,000

• anemia only if significant bleeding otherwise normal red cell indices, WBC count and differential, normal coagulation parameters

• peripheral blood smear- schistocytes

LAB TESTS

• HIV and Hep C • coagulation studies • Helicobacter pylori • thyroid funtion • rheumatological studies • Vitamin B12 and folate levels • anti-platelet antibody testing- NO

BONE MARROW EXAM

• not always needed, but do if the etiology of thrombocytopenia is unclear

• any abnormality with History/Physical, blood smear or blood indices

• yes for those older than 60 years

DIFFERENTIAL DIAGNOSIS

• drug induced • infections • liver disease and hypersplenism • microangiopathic processes • MDS and other bone marrow disorders • vasculitic purpura

ASH GUIDELINES/MANAGEMENT OF ITP

INITIAL MANAGEMENT• consider treatment for patients with a platelet count

<30,000 • longer courses of corticosteroids are preferred over

shorter courses of corticosteriods or IVIG • IVIG may be used in conjunction with corticosteriods if a

more rapid increase in platelet count is required • either IVIG (1g.kg for one dose, repeated as necessary)

or anti-D (in appropriate patients) may be used as a first line treatment if corticosteriods are contraindicated

ASH GUIDELINES FOR SENCOND LINE THERAPY

• splenectomy • rituximab • thrombopoientin receptor agonist • high dose dexamethasone • immunosuppression