DGTI: Transfusion doctors find cause of cerebral vein thrombosis
26.03.2021 11:03
When vaccinated against the SARS-CoV-2 virus, the immune system reacts. In very rare cases, complications can arise, such as thrombosis. However, experts from the German Society for Transfusion Medicine and Immunohematology (DGTI) have now found out why such reactions occur and how they can be treated. The specialist society sees these results as a milestone in overcoming the corona pandemic.
Cerebral vein thrombosis can occur in very rare cases in connection with vaccination with the AstraZeneca vaccine. This leads to the blockage of a vein in the brain - triggered by a blood clot. Transfusion physicians led by the Greifswald researcher Professor Dr. med. Andreas Greinacher have discovered what triggers these thromboses and how they can be treated. “This is real progress because people can now be vaccinated with this vaccine without hesitation,” said Greinacher about the importance of the research results. The complications only occur in extremely rare cases. “If cerebral vein thromboses occur in the future, we can treat them successfully,” says the expert, who is head of the transfusion medicine department at the Institute for Immunology and Transfusion Medicine at Greifswald University Medical Center.
After a vaccination, the body produces antibodies. In very rare cases, vaccinated people produce special antibodies that bind to thrombocytes, also known as platelets. The blood platelets are activated by the binding. Normally, these platelets seal damage to vessels during wound healing so that bleeding can be stopped. If platelets are activated without bleeding, clots can form in the blood, which can block the vessels. A so-called thrombosis occurs. “It is still unclear what exactly triggers the formation of the special antibodies, but we are continuing to research it,” says Greinacher.
Transfusion doctors led by Professor Greinacher have now examined the blood of seven affected people in order to understand the development of the thrombosis. The researchers have also developed a test procedure that helps detect the antibodies that appear after vaccination. “This procedure tests whether the special antibodies are present in the blood. This test can be used if symptoms of thrombosis occur after vaccination,” says Greinacher. People who experience leg pain or an unusually severe headache after vaccination should seek medical attention immediately. The immune reaction that occurs one to two days after vaccination must be distinguished from complications that usually only become noticeable from day four after vaccination. “I therefore advise patients to see a doctor if they still have symptoms after three days or if they appear again after a short break,” says the transfusion doctor. Since it is very unlikely that thrombosis will form after a vaccination, the expert emphasizes that there is no reason to start testing for thrombosis one to two days after vaccination if there are mild immune reactions.
The researchers have also found a treatment method. The blood platelets can be blocked by an intravenous immunoglobulin (ivIgG), so that the mechanism is inhibited. The blood clots can then be dissolved using anticoagulant medication. The diagnosis is made by the treating doctor on site; the therapy should be available in every medium-sized hospital.
“The research results are of great importance for the further management of the pandemic, as the AstraZeneca vaccine can continue to be used and there are now treatment options for the very rare thromboses,” said Professor Dr. med. Hubert Schrezenmeier, 1st Chairman of the DGTI. From the expert's point of view, this shows once again what an important role transfusion medicine has in research and treatment during the corona pandemic.