Pulmonary Embolism as a Complication of Sars- Cov-2 Infection and Complement Mediated Autoimmune Hemolytic Anemia

Abstract

SARS-Cov2 infection, especially in the acute phase, has been in many cases associated to the development of hypercoagulable states and a subsequent increased risk of venous thromboembolism [1]. The prevalence of pulmonary embolism (PE) has been shown to be higher in COVID-19 hospitalized patients compared to critically ill ones who test negative for the viral infection [2]. This is the reason why current guidelines of the International Society of Thrombosis and Haemostasis recommend the administration of thromboembolic prophylaxis in all hospitalized patients with SARS-CoV-2 infection or the use of a therapeutic dose of anticoagulant in the most critical cases. Although the pathophysiology underlying the onset of hypercoagulability during SARS-CoV-2 infection is yet not fully understood, the triggering of a powerful inflammatory response together with the role of cytokines and angiotensin converting enzyme 2 (ACE2) receptor, have shown to be able to induce endothelial cell dysfunction and damage with the subsequent onset of hypercoagulability [1]. The presence of activated neutrophils and macrophages in the target tissues has been associated with the induction of neutrophil extracellular traps (NETs) and thrombocytogenesis, promoting vascular collapse, respiratory distress up to a stage of multiorgan failure [3]. Several studies analysing the potential role of SARS-Cov-2 have shown that viral infection can induce immune system dysregulation through phenomena of epitope spreading, bystander activation, cross-reaction or molecular mimicry [4]. In particular, a limited number of autoimmune haemolytic anaemia (AIHA) cases have been reported in patients with SARS-CoV-2 infection, especially in those presenting with a severe clinical displays [5]. Here we report the case of a patient who was admitted to our Internal Medicine Ward diagnosed with warm autoimmune haemolytic anaemia (wAIHA) and pulmonary embolism (PE) with a recent COVID-19 infection.