Background: Severe coronavirus disease 2019 (Covid-19) is a systemic multi-organ viral invasion. Previous studies found that many patients had a procoagulant state and/or severe hypoxemia with relatively well-preserved lung mechanics. Mechanisms underlying the vascular and its surrounding tissue are not well known yet. Histological data in Covid-19 tissues´ patients are still limited and mainly focused on post-mortem analysis. Since SARS-CoV-2 largely affects cutaneous tissue, we aim to examine in depth skin lesions related to Covid-19 in order to understand better how the disease might affect living tissue. Methods: Five skin lesions from Covid-19 adult patients were selected for histological tissue examination. Vast amount of data of immunohistochemistry (IHC) and direct immuno uorescent (DIF) were part of the assessment. Results: A common strong vasculopathic reaction pattern based on prominent vascular endothelial and myointimal cellgrowth was identi ed. Endothelial cell distortion generated vascular lumen obliteration and a strike erythrocyte and serum extravasation. Extensive signi cant vascular C4d and C3 deposition throughout vascular cell wall was also identi ed. A regenerative epidermal hyperplasia with tissue structure preservation was found. Conclusions: Covid-19 could comprise an obliterative micro-angiopathy consisting on endothelial and myointimal intensive growth with complement activation. This mechanism, together with increased vascular permeability identi ed, could contribute to obliterative vascular lumen and hemorrhage in Covid-19. Activation of the complement and angiogenic pathways could have an important role in inducing and maintaining this vasculopathic reaction pattern. Thus, anticoagulation by itself could not completely reverse vascular lumen obliteration, with consequent hemorrhagic increased risk associated. Skin is the largest organ in the body, the most accessible one and can mirror other organs of the body. Findings of this study could contribute to a better understanding of physio-pathological mechanisms underlying SARS-CoV-2 infection on living tissue and could help further studies nd potential targets for speci c therapeutic interventions in Covid-19 severe patients.

Background Clinical features and outcomes of patients with spontaneous ilio-psoas hematoma (IPH) in intensive care units (ICUs) are poorly documented. The objectives of this study were to determine epidemiological, clinical, biological and management characteristics of ICU patients with IPH.Methods We conducted a retrospective multicentric study in three French ICUs from January 2006 to December 2014. We included IPH diagnosed both at admission and during ICU stay. Surgery and embolization were available 24 h a day for each center, and therapeutic decisions were undertaken after pluridisciplinary discussion. All IPHs were diagnosed using CT scan.ResultsDuring this period, we identified 3.01 cases/1000 admissions. The mortality rate of the 77 included patients was 30 %. In multivariate analysis, we observed that mortality was independently associated with SAPS II (OR 1.1, 95 % CI [1.013–1.195], p = 0.02) and with the presence of hemorrhagic shock (OR 67.1, 95 % CI [2.6–1691], p = 0.01). We found IPH was related to anticoagulation therapy in 56 cases (72 %), with guideline-concordant reversal performed in 33 % of patients. We did not found any association between anticoagulant therapy type and outcome.ConclusionWe found IPH is an infrequent disease, with a high mortality rate of 30 %, mostly related to anticoagulation therapy and usually affecting the elderly. Management of anticoagulation-related IPH includes a high rate of no reversal of 38 %.