Pulmonary thromboembolism and deep venous thrombosis occur frequently in hospitalised patients with COVID-19, the prevalence increases on the intensive care unit (ICU) and is very high in patients on ...extracorporeal membrane oxygenation (ECMO). We undertook a literature review to assess the usefulness of screening for peripheral venous thrombosis or pulmonary thrombosis in patients admitted with COVID-19. Outside of the ICU setting, D-dimer elevation on presentation or marked increase from baseline should alert the need for doppler ultrasound scan of the lower limbs. In the ICU setting, consideration should be given to
routine
screening with doppler ultrasound, given the high prevalence of thrombosis in this cohort despite standard anticoagulant thromboprophylaxis. However, absence of lower limb thrombosis on ultrasound does not exclude pulmonary venous thrombosis. Screening with CT pulmonary angiography (CTPA) is not justified in patients on the general wards, unless there are clinical features and/or marked elevations in markers of COVID-19-associated coagulopathy. However, the risk of pulmonary embolism or pulmonary thrombosis in ICU patients is very high, especially in patients on ECMO, where studies that employed routine screening for thrombosis with CT scanning have uncovered up to 100% incidence of pulmonary thrombosis despite standard anticoagulant thromboprophylaxis. Therefore, in patients at low bleeding risk and high clinical suspicion of venous thromboembolism, therapeutic anticoagulation should be considered even before screening, Our review highlights the need for increased vigilance for VTE, with a low threshold for doppler ultrasound and CTPA in high risk in-patient cohorts, where clinical features and D-dimer levels may not accurately reflect the occurrence of pulmonary thromboembolism.
Anosmia, the loss of smell, is a common and often the sole symptom of COVID-19. The onset of the sequence of pathobiological events leading to olfactory dysfunction remains obscure. Here, we have ...developed a postmortem bedside surgical procedure to harvest endoscopically samples of respiratory and olfactory mucosae and whole olfactory bulbs. Our cohort of 85 cases included COVID-19 patients who died a few days after infection with SARS-CoV-2, enabling us to catch the virus while it was still replicating. We found that sustentacular cells are the major target cell type in the olfactory mucosa. We failed to find evidence for infection of olfactory sensory neurons, and the parenchyma of the olfactory bulb is spared as well. Thus, SARS-CoV-2 does not appear to be a neurotropic virus. We postulate that transient insufficient support from sustentacular cells triggers transient olfactory dysfunction in COVID-19. Olfactory sensory neurons would become affected without getting infected.
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•A postmortem bedside surgical procedure was developed for COVID-19 and control patients•Ciliated cells are the main target cell type for SARS-CoV-2 in the respiratory mucosa•Sustentacular cells (non-neuronal) are the main target cell type in the olfactory mucosa•No evidence for infection of olfactory sensory neurons or olfactory bulb parenchyma
Postmortem samples of respiratory and olfactory mucosa and whole olfactory bulbs are harvested immediately after the death of COVID-19 patients revealing ciliated cells and sustentacular cells but not olfactory sensory neurons as the main target cell types for SARS-CoV-2 infection and replication.
Increasing age and renal impairment are risk factors for venous thrombosis but also for anticoagulant-induced bleeding. In large-scale phase III trials, non-VKA oral anticoagulants (NOACs) were at ...least as effective and safe for the treatment of acute venous thromboembolism as warfarin. Here, we review the efficacy and safety of dabigatran, rivaroxaban, apixaban and edoxaban in the subgroups of elderly patients (≥75 years) and patients with impaired renal function (creatinine clearance ≤50 ml/min). In all phase III trials, the efficacy of NOACs in the prevention of recurrent VTE was conserved both in the elderly subgroup and in the subgroup with impaired renal function. In a meta-analysis of the pooled results, NOACs reduced VTE recurrence compared with warfarin in elderly patients. In elderly patients and patients with impaired renal function, the safety of NOACs was in line with the results of the overall study. NOACs may offer an effective, safer and more convenient alternative for VKAs also in the elderly. However, the efficacy/safety profile of NOACs in the aged population needs to be confirmed in real-life.
Harlequin Syndrome (also known as North-South Syndrome) is a complication of veno-arterial extracorporeal membrane oxygenation (V-A ECMO) that can occur when left ventricular function starts to ...recover. While most commonly due to continued impaired gas exchange in the lungs, we present a case caused by right ventricular dysfunction, successfully managed by conversion of the ECMO circuit to a veno-veno-arterial (VV-A) configuration.
We review the evidence for tranexamic acid (TXA) for the treatment and prevention of bleeding caused by surgery, trauma and bleeding disorders. We highlight therapeutic areas where evidence is ...lacking and discuss safety issues, particularly the concern regarding thrombotic complications.
An electronic search was performed in PubMed and the Cochrane Library to identify clinical trials, safety reports and review articles.
TXA reduces bleeding in patients with menorrhagia, and in patients undergoing caesarian section, myomectomy, hysterectomy, orthopedic surgery, cardiac surgery, orthognathic surgery, rhinoplasty, and prostate surgery. For dental extractions in patients with bleeding disorders or taking antithrombotic drugs, as well as in cases of idiopathic epistaxis, tonsillectomy, liver transplantation and resection, nephrolithotomy, skin cancer surgery, burn wounds and skin grafting, there is moderate evidence that TXA is effective for reducing bleeding. TXA was not effective in reducing bleeding in traumatic brain injury and upper and lower gastrointestinal bleeding. TXA reduces mortality in patients suffering from trauma and postpartum hemorrhage. For many of these indications, there is no consensus about the optimal TXA dose. With certain dosages and with certain indications TXA can cause harm, such as an increased risk of seizures after high TXA doses with brain injury and cardiac surgery, and an increased mortality after delayed administration of TXA for trauma events or postpartum hemorrhage. Whereas most trials did not signal an increased risk for thrombotic events, some trials reported an increased rate of thrombotic complications with the use of TXA for gastro-intestinal bleeding and trauma.
TXA has well-documented beneficial effects in many clinical indications. Identifying these indications and the optimal dose and timing to minimize risk of seizures or thromboembolic events is work in progress.
Adhesion of Staphylococcus aureus to blood vessels under shear stress requires von Willebrand factor (VWF). Several bacterial factors have been proposed to interact with VWF, including VWF-binding ...protein (vWbp), a secreted coagulase that activates the host's prothrombin to generate fibrin. We measured the adhesion of S aureus Newman and a vWbp-deficient mutant (vwb) to VWF, collagen, and activated endothelial cells in a microparallel flow chamber. In vivo adhesion of S aureus was evaluated in the mesenteric circulation of wild-type (WT) and VWF-deficient mice. We found a shear-dependent increase in adhesion of S aureus to the (sub)endothelium that was dependent on interactions between vWbp and the A1-domain of VWF. Adhesion was further enhanced by coagulase-mediated fibrin formation that clustered bacteria and recruited platelets into bacterial microthrombi. In vivo, deficiency of vWbp or VWF as well as inhibition of coagulase activity reduced S aureus adhesion. We conclude that vWbp contributes to vascular adhesion of S aureus through 2 independent mechanisms: shear-mediated binding to VWF and activation of prothrombin to form S aureus–fibrin–platelet aggregates.
•vWbp mediates adhesion of S aureus under flow to activated endothelial cells and the subendothelium via VWF.•vWbp activates prothrombin and triggers the formation of bacteria–fibrin–platelet aggregates, which enhance adhesion to vessels under flow.
On March 11, 2020 the World Health Organization declared COVID‐19 pandemic, leading to a subsequent impact on the entire world and health care system. Since the causing Severe Acute Respiratory ...Syndrome Coronavirus 2 houses in the aerodigestive tract, activities in the gastrointestinal outpatient clinic and endoscopy unit should be limited to emergencies only. Health care professionals are faced with the need to perform endoscopic or endoluminal emergency procedures in patients with a confirmed positive or unknown COVID‐19 status. With this report, we aim to provide recommendations and practical relevant information for gastroenterologists based on the limited amount of available data and local experience, to guarantee a high‐quality patient care and adequate infection prevention in the gastroenterology clinic.
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