"Introduction
TMA [thrombotic microangiopathy] is a syndrome characterized by clinical and pathological features. It can be further classified into hereditary and acquired. Clinical features include microangiopathic hemolytic anemia, thrombocytopenia, and organ injury, while pathological features suggest vascular damage as evident by arteriolar and capillary thrombosis.
Here, we describe two patients, both young men, who were treated at our institution in 2021. Both patients presented with a full-blown picture of TMA following COVID-19 vaccination...
Discussion
It has been established that the ChAdOx1 nCoV-19 adenoviral vector vaccine against SARS-CoV-2 is associated with vaccine-induced immune thrombocytopenia and thrombosis (VITT) and other possible hematological phenomena, such as development of de novo complement mediated hemolytic or an exacerbation of pre-existing complement mediated hemolytic anemia.
TMA are a group of disorders characterized by the presence of MAHA [microangiopathic hemolytic anemia], thrombocytopenia, and end-organ capillary thromboses. TMAs are a syndrome of capillary and arteriolar thrombosis that can have a variety of causes. There are few suggestive mechanisms on how the COVID-19 virus can cause TMAs such as direct viral toxicity to vascular endothelium, microvascular thrombosis, and complement-mediated disorder...
As the number of available vaccines increased throughout the world, serious adverse effects were observed following immunization. These include TMA, TTS [thrombocytopenia syndrome], and VITT...
Our first patient presented within a week of COVID-19 vaccination, in concordance with average timeline reported in the literature, i.e., 5-30 days (median of 4-16 days), post-SARS-CoV-2 immunization. The initial abnormalities of acute kidney injury and MAHA evident by the presence of schistocytes and thrombocytopenia were suggestive of a picture of aHUS [atypical hemolytic uremic syndrome] ..
In our second patient, SARS-CoV-2 vaccination was the most likely trigger of TMA... which occurred seven days after receiving the first dose of ChAdOx1 nCoV-19 adenoviral vector vaccine...
Although our patients have not fully made a recovery of their renal function in the short-term follow-up we have had, other patients might regain function fully and lead normal lives if acted upon early in their treatment course...
Conclusions
... TMA post-COVID-19 vaccination is a well-recognized complication and carries a drastic sequela if not identified early."
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Salem et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.