Blood reviews
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As activation of the coagulation pathway is a physiological response to injury, the development of disseminated intravascular coagulation (DIC) is a warning signal to the clinician that the primary pathological disease state is decompensating. In pregnancy, DIC can occur in several settings, which include emergencies such as placental abruption and amniotic fluid embolism as well as complications such as pre-eclampsia. Whilst the acuteness of the event and the proportionality in the coagulant and fibrinolytic responses may vary between these different conditions, a common theme for pregnancy-associated DIC is the pivotal role played by the placenta. ⋯ This is necessary because DIC itself can have pathological consequences that translate clinically into a worse prognosis for affected patients. This article will describe how pregnancy-associated DIC can be diagnosed promptly and how treatment should be managed strategically. It also discusses the latest developments in our understanding of haemostatic mechanisms within the placenta and how these may have relevance to new diagnostic approaches as well as novel therapeutic modalities.
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Spontaneous intracerebral haemorrhage is one of the most feared complications of long-term anticoagulation. Warfarin therapy not only increases the likelihood of suffering an intracranial haemorrhage, but also increases the mortality associated with it. ⋯ The specific management of patients with prosthetic heart valves is also discussed. A summary of current societal guidelines is also included, as are some key practice points.
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Idiopathic erythrocytosis is an uncommon disease, and is defined by an increase in red blood cell mass. The differential diagnosis of erythrocytosis is extensive, and can be divided into primary and secondary forms. Primary erythrocytoses are due to intrinsic defects in erythroid precursor cells and are characterized by low erythropoietin levels. ⋯ A distinct subset of secondary erythrocytoses are due to genetic mutations in key proteins of the oxygen-sensing pathway. These proteins constitute the core molecular machinery of oxygen-sensing with respect to red blood cell control. Apart from assigning physiologic roles for these proteins, studies of these rare mutations have (i) revealed the exquisite sensitivity of this pathway to genetic perturbations, (ii) highlighted important functional regions of the proteins, and (iii) provided a basis for potentially targeting this pathway for therapeutic benefit.
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Iron overload diseases of genetic origin are an ever changing world, due to major advances in genetics and molecular biology. Five major categories are now established: HFE-related or type1 hemochromatosis, frequently found in Caucasians, and four rarer diseases which are type 2 (A and B) hemochromatosis (juvenile hemochromatosis), type 3 hemochromatosis (transferrin receptor 2 hemochromatosis), type 4 (A and B) hemochromatosis (ferroportin disease), and a(hypo)ceruloplasminemia. ⋯ The combination of magnetic resonance imaging (for diagnosing visceral iron overload) and of genetic testing has drastically reduced the need for liver biopsy. Phlebotomies remain an essential therapeutic tool but the improved understanding of the intimate mechanisms underlying these diseases paves the road for innovative therapeutic approaches.
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While there is good evidence for a protective effect of aspirin against occlusive vascular events in individuals with arterial disease, its role in preventing venous thromboembolism (VTE) is unclear. In this article we review the role of aspirin and other antiplatelet drugs in prevention of venous thromboembolism in surgical patients, high risk medical patients requiring aspirin for other reasons, patients with myeloproliferative disorders, long distance travellers and patients receiving treatment with the IMiD class of drugs. Overall, data from the PEP study and Anti-Platelet Trialists' systematic review show that aspirin reduces the risk of VTE by around 25% in high risk surgical patients. ⋯ In patients who require aspirin because of high risk of arterial vascular occlusion (including patients with polycythaemia vera and essential thrombocythaemia), the additional small reduction in VTE risk is an added benefit with no additional risk associated. There is no evidence for a role of aspirin in prevention of travel-related thrombosis. At present there is no clear evidence that aspirin is the drug of choice for the prevention of VTE in any patient group.