Introduction Autoimmune lymphoproliferative syndrome (ALPS) was first described in 1967 when Canale and Smith reported on five children with massive lymphadenopathy and splenomegaly mimicking lymphoma. In 1992 Sneller et al. similarly described two patients with a progressive lymphoproliferative disorder associated with…
Epidemiology The reported incidence of heparin-induced thrombocytopenia (HIT) after heparin exposure is 0.2%–7%, though the accuracy of such estimates is limited by the challenges of disease recognition and diagnosis. Risk factors may be host- or heparin-related. Heparin-Related Risk Factors The…
Introduction Drug-induced thrombocytopenia (DIT) is a common clinical problem, and numerous drugs have been implicated in the development of thrombocytopenia. The risk of thrombocytopenia after any drug is low, and only a small number of patients taking a suspected medication…
Introduction Immune thrombocytopenia (ITP) is a bleeding disorder characterized by immune-mediated platelet destruction with resultant thrombocytopenia and mucocutaneous bleeding. Chronic ITP is defined by ITP persistence beyond 12 months, with spontaneous recovery occurring in less than 10% of adults. The…
Immune thrombocytopenia (ITP) is a bleeding disorder characterized by immune-mediated platelet destruction and resultant thrombocytopenia. Two forms of ITP had been described previously: acute ITP that resolves within 6 months and chronic ITP that persists beyond 6 months. Recently, an…
There are countless mechanisms for causing platelet abnormalities, many of which are likely yet to be discovered. This chapter is meant to touch on additional platelet abnormalities not completely discussed in other chapters of this book—but is not by any…
Multiple platelet signaling and synthetic pathways are necessary for the optimal propagation and stabilization of the forming thrombus. Mutations in platelet receptors, signaling proteins, and synthetic pathways have been identified in patients with granule release and aspirin-like defects. Patients with…
Platelets contain two major types of granules, dense and α-granules. Granule contents include numerous factors essential to the normal formation and stabilization of a hemostatic plug. Either a decrease in the number of platelet granules or a defect in their…
Glanzmann thrombasthenia (GT) is an autosomal-recessive platelet function disorder in which platelet appearance and platelet number are unaffected. Patients with GT present with platelet-type bleeding, which may be severe, such as purpura, epistaxis, oral mucosal bleeding, menorrhagia, or gastrointestinal bleeding.…
GPIb-IX is the major platelet receptor for von Willebrand factor (VWF). Normal GPIb-IX function is essential both for normal megakaryocyte/platelet maturation and for normal platelet function, most prominently adhesion. Mutations in GPIb-IX result in a number of different syndromes. Clinical…