Uzroci trombocitopenije u COVID-19 bolesnika

master's thesis

• Title (english): Causes of thrombocytopenia in COVID-19 patients
• Author: Dora Bežovan
• Mentor: Zdravko Mitrović (mentor)
• Committee member: Rajko Kušec (predsjednik povjerenstva)
• Committee member: Jasenka Markeljević (član povjerenstva)
• Committee member: Zdravko Mitrović (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; (Department of Internal Medicine); Zagreb
• Defense date and country: 2021-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences; Internal Medicine

Abstract

Trombociti su mali stanični fragmenti čija je primarna funkcija regulacija hemostaze, a imaju funkciju i u imunološkom sustavu. Pad njihovog broja ispod 150 × 109/L definira trombocitopeniju, a ispod 100 × 109/L klinički značajnu trombocitopeniju. Trombocitopenija je česta u virusnim infekcijama i najčešći je hemostatski poremećaj u pacijenata koji se nalaze na odjelima za intenzivnu skrb. Trombocitopenija je prisutna u prosječno 18% oboljelih od bolesti COVID-19, obično je blaga, a komplikacije u smislu krvarenja su rijetke. Zastupljenija je među teže oboljelima i predstavlja neovisan čimbenik rizika za loš ishod i mortalitet. Mnogobrojni uzroci mogu dovesti do trombocitopenije u oboljelih od bolesti COVID-19, a uključuju smanjenu proizvodnju trombocita, njihovo povećano uništavanje i potrošnju te trombocitopeniju uzrokovanu lijekovima. Smanjenje proizvodnje trombocita može nastati zbog oštećenja hematopoetskih progenitora izravnim djelovanjem virusom ili štetnim učinkom citokinske oluje te zbog oštećenja kapilarne mreže pluća čime se onemogućuje fragmentacija megakariocita u plućima. Nadalje, u sklopu bolesti COVID-19 može se razviti imuna trombocitopenija čime se povećava uništavanje trombocita. Može doći i do hiperaktivacije trombocita potaknute mnogim uzrocima koja također vodi povećanom uništavanju trombocita, ali i njihovoj povećanoj potrošnji u stvaranju ugrušaka. Do povećane potrošnje u stvaranju ugrušaka može doći i zbog trombotske mikroangiopatije koja se može očitovati kao trombotska trombocitopenična purpura te kao komplementom posredovan hemolitičko-uremični sindrom. Trombocitopenija može biti izazvana heparinom koji se koristi za tromboprofilaksu oboljelih od bolesti COVID-19, ali i drugim brojnim lijekovima koji pacijenti mogu imati u svojoj terapiji. Specifično liječenje trombocitopenije moguće je kod imune trombocitopenije, trombotske mikroangiopatije i trombocitopenije uzrokovane lijekovima, a kod drugih uzroka terapija je liječenje bolesti COVID-19 i njenih komplikacija. U ovom diplomskom radu težište je stavljeno na analizu mehanizama koji dovode do trombocitopenije u oboljelih od bolesti COVID-19.

Abstract (english)

Platelets are small cell fragments whose primary function is the regulation of hemostasis, but they also have a function in the immune system. A decrease in their number below 150 × 109/L defines thrombocytopenia and below 100 × 109/L a clinically significant thrombocytopenia. Thrombocytopenia is frequent in virus infections and is the most common hemostatic disorder in patients at intensive care unit. Thrombocytopenia is present in approximately 18% of COVID-19 patients. It is usually mild and bleeding complications are rare. It is more represented among severely ill whereby it is an independent risk factor for poor outcome and mortality. Numerous causes can lead to thrombocytopenia in COVID-19 patients. Basic classification refers to decreased platelet production, their increased destruction and consumption, and drug-induced thrombocytopenia. Decreased platelet production may occur due to a damage to hematopoietic progenitors by direct impact of the virus or the detrimental effect of a cytokine storm and due to damage to the capillary network of the lungs, which prevents the fragmentation of megakaryocytes in the lungs. Furthermore, immune thrombocytopenia can develop in COVID-19 thereby increasing platelet destruction. Platelet hyperactivation can occur due to many causes, which also leads to an increased destruction of platelets, but also to their increased consumption in the formation of clots. The increased consumption in clot formation may also be due to thrombotic microangiopathy, that may present as thrombotic thrombocytopenic purpura and as a complement-mediated hemolytic-uremic syndrome. Thrombocytopenia can be caused by heparin, which is used for thromboprophylaxis in patients with COVID-19, but also by many other drugs used for treatment. The specific treatment of thrombocytopenia is possible in immune thrombocytopenia, thrombotic microangiopathy, and drug-induced thrombocytopenia. In other causes the therapy is the treatment of COVID-19 and its complications. In this thesis, the focus is on the analysis of the mechanisms leading to thrombocytopenia in COVID-19 patients.

• Keywords: trombocitopenija; COVID-19; SARS-CoV-2
• Keywords (english): thrombocytopenia; COVID-19; SARS-CoV-2
• Language: croatian
• URN:NBN: urn:nbn:hr:105:002711
• Study programme: Title: Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-01-21 10:40:11