Human genetics. To clot or not

[Acute coronary syndrome. A diffuse diagnosis]

Acute coronary syndrome is one of the most common reasons for a presentation in an emergency room. The biggest component of the overall mortality in adults is acute coronary syndrome or in this context its complications. The term "acute coronary syndrome" comprises on one hand 3 entities--unstable angina pectoris, Non-ST-elevation myocardial infarction and ST-elevation myocardial infarction. On the other hand particularly in emergency medicine the term is used as a working diagnosis for patients with unclear, acute chest pain. Although the underlying disease has not changed, especially with the introduction of troponins and the changes of their reference values the concept and importance of acute myocardial infarction has changed. This article emphasises on the current nomenclature and its importance for the adequate diagnosis and treatment are explained.

Acute coronary syndromes: diagnosis and management, part I

The term acute coronary syndrome (ACS) refers to any group of clinical symptoms compatible with acute myocardial ischemia and includes unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). These high-risk manifestations of coronary atherosclerosis are important causes of the use of emergency medical care and hospitalization in the United States. A quick but thorough assessment of the patient's history and findings on physical examination, electrocardiography, radiologic studies, and cardiac biomarker tests permit accurate diagnosis and aid in early risk stratification, which is essential for guiding treatment. High-risk patients with UA/NSTEMI are often treated with an early invasive strategy involving cardiac catheterization and prompt revascularization of viable myocardium at risk. Clinical outcomes can be optimized by revascularization coupled with aggressive medical therapy that includes anti-ischemic, antiplatelet, anticoagulant, and lipid-lowering drugs. Evidence-based guidelines provide recommendations for the management of ACS; however, therapeutic approaches to the management of ACS continue to evolve at a rapid pace driven by a multitude of large-scale randomized controlled trials. Thus, clinicians are frequently faced with the problem of determining which drug or therapeutic strategy will achieve the best results. This article summarizes the evidence and provides the clinician with the latest information about the pathophysiology, clinical presentation, and risk stratification of ACS and the management of UA/NSTEMI.

Acute coronary syndromes: diagnosis and management, part I

The term acute coronary syndrome (ACS) refers to any group of clinical symptoms compatible with acute myocardial ischemia and includes unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). These high-risk manifestations of coronary atherosclerosis are important causes of the use of emergency medical care and hospitalization in the United States. A quick but thorough assessment of the patient's history and findings on physical examination, electrocardiography, radiologic studies, and cardiac biomarker tests permit accurate diagnosis and aid in early risk stratification, which is essential for guiding treatment. High-risk patients with UA/NSTEMI are often treated with an early invasive strategy involving cardiac catheterization and prompt revascularization of viable myocardium at risk. Clinical outcomes can be optimized by revascularization coupled with aggressive medical therapy that includes anti-ischemic, antiplatelet, anticoagulant, and lipid-lowering drugs. Evidence-based guidelines provide recommendations for the management of ACS; however, therapeutic approaches to the management of ACS continue to evolve at a rapid pace driven by a multitude of large-scale randomized controlled trials. Thus, clinicians are frequently faced with the problem of determining which drug or therapeutic strategy will achieve the best results. This article summarizes the evidence and provides the clinician with the latest information about the pathophysiology, clinical presentation, and risk stratification of ACS and the management of UA/NSTEMI.

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome and adult onset Still's disease: case report and review of the literature

Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP/HUS) is a multisystem disorder characterized by consumptive thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal function abnormalities, and fever. Coexistence of TTP/HUS and adult onset Still's disease (ASD) is extremely rare. We report the case of a 46-year-old woman who presented with fever, arthritis, myalgias, petechia on skin and confusion five years after the onset of ASD. Thrombocytopenia, renal failure, marked elevation lactate dehydrogenase, and red cell fragmentation on peripheral blood smear were observed. We made a diagnosis of TTP/HUS associated with ASD, according to physical examination and characteristic laboratory data. She recovered from the TTP/HUS following daily sessions of therapeutic plasma exchange with fresh frozen plasma replacement and glucocorticoid therapy. Awareness of the possible development of TTP/HUS in ASD is important for early diagnosis and treatment.

Thrombotic thrombocytopenic purpura in systemic lupus erythematosus: disease activity and the use of cytotoxic drugs

Thrombotic thrombocytopenic purpura (TTP) is a rare and occasionally fatal haematologic disorder that can coexist with systemic lupus erythematosus (SLE) and other autoimmune diseases. We identified all cases of TTP seen in our institution over a 3 year period using a computerized database. We found that SLE activity (measured by the SLE Disease Activity Index) and TTP activity ran a parallel course in three patients with coexistent SLE and TTP. TTP in these three patients, although refractory to plasmapheresis, responded to cytotoxic therapy. These observations further support an autoimmune contribution to the pathogenesis of some cases of TTP. A literature review revealed that mortality in SLE patients with more severe, refractory TTP treated with plasmapheresis and cytotoxics, may not be higher than in patients responding to plasmapheresis alone (who are likely to have milder disease). These data suggest that cytotoxics may have a role in treatment of patients with active SLE and TTP refractory to plasmapheresis.

Pathogenetic concepts of acute coronary syndromes

The propensity of plaque to disrupt is a major determinant of future ischemic events. Although they are distinct from one another, the atherosclerotic and thrombotic processes appear to be interdependent and may be integrated under the term "atherothrombosis." It is now clear that plaque composition, rather than the percent stenosis, is a major determinant of plaque vulnerability. Plaque disruption seems to depend on both passive and active phenomena and is not purely mechanical. Inflammation (activation of monocytes/macrophages) is a major determinant of both plaque vulnerability and thrombogenicity as they relate to plaque disruption. In one-third of acute coronary syndromes, there is, however, no plaque disruption but only superficial erosion of a markedly stenotic, fibrotic plaque. In these cases, thrombus formation may be exacerbated by a hyperthrombogenic state present in patients with certain systemic risk factors. The endothelium plays a pivotal role in vascular homeostasis and hemostasis. This dynamic organ regulates blood thrombogenicity as well as contractile, secretory, and mitogenic activities in the vessel wall. Some classic risk factors induce endothelial dysfunction by reducing the bioavailability of nitric oxide, increasing tissue endothelin-1, and activating pro-inflammatory signaling pathways. Vascular hemostasis, which is the maintenance of blood fluidity and vascular integrity, is achieved by counter-balancing the intrinsic clotting tendency of blood. As a consequence of the central role of endothelial cells in hemostatic control, a dysfunctional endothelium will generate a pro-thrombotic environment favoring development of atherosclerotic lesions and thrombotic complications.

Thrombotic thrombocytopenic purpura (TTP)--an enigmatic disease finally resolved?

Thrombocytopenic thrombocytopenic purpura (TTP), characterized by hemolytic anemia, thrombocytopenia and fluctuating neurological abnormalities, was almost universally fatal until in the 1970s, when it was discovered that remissions could usually be achieved by exchanging plasma from patients with that of donors. For the following 25 years, this therapy was routinely used without any real understanding of why it was effective. Three recent papers published almost simultaneously offer insights into the molecular basis of TTP, a rationale for why plasma exchange is helpful, and avenues for development of new and highly specific therapeutic agents.