Snapshot A 42-year-old man presents to his primary care physician's office for easy bruising and gingival bleeding. He reports his symptoms began one day prior to presentation and has never occurred before. Medical history is significant for a recently diagnosed hepatitis C infection. On physical exam, there is mild bleeding of the gums. There are petechiae throughout the chest, arms, and legs. There is no evidence of splenomegaly on abdominal exam. A complete blood count is significant for a platelet count of 24,000/μL and peripheral blood smear demonstrates enlarged platelets. He is started on corticosteroids. Introduction Clinical definition acquired immune-mediated destruction of otherwise normal platelets Epidemiology Demographics 1-7 years of age commonly in children Etiology Primary ITP unknown Secondary ITP autoimmune disorders login to view 2 more bullets infection login to view 2 more bullets malignancy login to view 1 more bullet vaccinations Pathogenesis IgG antibodies directed against platelet membrane glycoproteins such as GPIIb/IIIa login to view 1 more bullet Classification Primary immune thrombocytopenia (ITP) immune-mediated thrombocytopenia without an underlying condition Secondary ITP immune-mediated thrombocytopenia with an underlying condition (e.g., HIV infection) Presentation Symptoms asymptomatic bleeding symptoms login to view 2 more bullets Physical exam petechiae purpura ecchymosis atypical to have a palpable spleen Studies CBC and platelet count Differential Hypersplenism distinguishing factor login to view 1 more bullet Liver disease distinguishing factor login to view 2 more bullets Microangiopathic hemolytic process (e.g., thrombotic thrombocytopenic purpura) distinguishing factor login to view 1 more bullet Diagnosis Making the diagnosis primary ITP login to view 1 more bullet secondary ITP login to view 1 more bullet rule out other causes login to view 3 more bullets Treatment Conservative observation login to view 2 more bullets Medical corticosteroids login to view 2 more bullets intravenous immunoglobulins (IVIG) login to view 2 more bullets Operative splenectomy login to view 2 more bullets Complications Fatal hemorrhage