Controversies and unresolved issues in antiphospholipid syndrome pathogenesis and management

While much is understood concerning the clinical features of patients with antiphospholipid syndrome (APS), many issues remain. The proper designation of patients with "definite" APS and the correct categorization of patients by both laboratory and clinical features are matters of ongoing debate. Recent proposals have identified new subsets of patients who have many typical features of APS but either do not fit the criteria for a "definite" diagnosis or have initially negative laboratory tests for antiphospholipid antibodies. Meanwhile, decisions about laboratory tests are based on expert opinion, rather than the results of controlled trials. As for treatment, many guidelines are offered, but few are backed by data from strong clinical trials. This article summarizes the clinical questions remaining to be answered and debates concerning pathogenesis, diagnosis, and management.

The relationship between the antiphospholipid syndrome and heparin-induced thrombocytopenia

Antiphospholipid syndrome (APS) and heparin-induced thrombocytopenia (HIT) are immune-mediated thrombotic conditions caused by antibodies targeted to a protein-antigen complex. Although each disorder is attributed to two distinct antibodies, these autoimmune disorders are characterized by a similar pathogenesis that includes a hypercoagulable state, platelet activation, damage to the vascular endothelium, and inflammation. APS and HIT share similarities in the clinical presentation because each is associated with thrombocytopenia, a high risk of thrombosis in all venous and arterial sites, and catastrophic thrombotic outcomes occur if untreated. Understanding the disease process for one disorder could potentially aid in understanding the other disorder.

Heparin-induced thrombocytopenia, paradoxical thromboembolism, and other adverse effects of heparin-type therapy

This article discusses the common and uncommon side effects of heparin and heparin-like therapy. Most attention is devoted to heparin-induced thrombocytopenia, as it is the most clinically aggressive adverse reaction. Additionally, less common and several newly reported side effects are discussed.