What is it HLH?
Hemophagocytic Lymphohistiocytosis (HLH) is a rare and often fatal syndrome of uncontrolled and ineffective inflammatory response to a certain trigger. It is characterized by excessive proliferation of lymphocytes and macrophages (histiocytes), hence the name “lymphohistiocytosis”. This results in the overproduction of cytokines, responsible for many of the clinical features present in this syndrome.
Familial, or genetic, HLH occurs as a result of a genetic mutation leading to impaired cytotoxic function. There have been several genetic mutations indicated in the development of HLH, including an association with congenital immunodeficiency syndromes, such as Chediak-Higashi, Griscelli and X-Linked Lymphoproliferative Syndromes. This form most often occurs within the first year of life (median age 8 months), with the majority of pediatric cases occurring <2 years of age, but can range from infancy to adulthood.
Acquired HLH occurs in the setting of an underlying condition, such as immunodeficiency, malignancy, or autoimmune disease. When HLH is secondary to a predisposing autoimmune disease, it is referred to as macrophage activating syndrome (MAS). Acquired HLH is the most common cause of this syndrome in adults, but this form can be seen in all ages. Overall, the syndrome is most often triggered by an infectious agent in an otherwise healthy person....Read More
Background: Factor Xa inhibitors have gained more use over the past several years due to the ease of administration and easier monitoring. However, bleeding, namely intracranial hemorrhage (ICH) is still a risk and the lack of a proven antidote is a cause for concern. Guidelines for the treatment of ICH published in 2016 recommended the administration of prothrombin complex concentrates (PCCs, both activated [aPCC] and 4 factor) . In 2018 andexanet alfa gained accelerated approval by the FDA for the reversal of factor Xa inhibitors. Despite this new antidote, many organizations such as the American Society of Hematology and the European Stroke Organization still recommend the use of PCCs. Research thus far has been performed in healthy volunteers, or small (<100 total patients with ICH) trials leaving a gap in the literature of what agent to use at the bedside....Read More
Early reports have shown that COVID-19 is most likely causing a hypercoagulable state, however the prevalence of acute VTE and exactly how to treat it is an evolving area. Limited data suggest pulmonary microvascular thrombosis may play a role in progressive respiratory failure. However, most evidence is limited to small retrospective trials. As we wait for more evidence, clinical decisions have to made at the bedside and decisions about pharmacological prophylaxis are starting to emerge. In this episode I sit down with a special guest that is new to REBEL Cast to talk about the dilemmas involving COVID-19 and thrombosis....Read More
Background: In patients with ICH, antiplatelet therapy is withheld due to the perceived risk of hematoma expansion. Often, these medications are either not restarted or there is prolonged delays until they are restarted, but the risk of occlusive vascular events might be higher without resumption of antithrombotic therapy. A meta-analysis of observational studies found no difference in the risk of hemorrhagic events and a lower risk of occlusive vascular events associated with antiplatelet therapy resumption after any type of intracranial hemorrhage (ICH); however, randomized trials for antiplatelet efficacy in occlusive vascular disease have excluded patients with a history of intracerebral hemorrhage. Due to the paucity of evidence, no guidelines have strong recommendations about long-term anti-platelet therapy after ICH. The RESTART Trial  aimed to address the question of whether or not to start antiplatelet therapy following an intracerebral hemorrhagic stroke. ...Read More