Cerebral vein sinus thrombosis – what is it? [WE EXPLAIN]

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Cerebral vein sinus thrombosis is not a common disease. The clots that block the blood flow usually happen elsewhere. However, after COVID-19 vaccines, thrombosis is noticed in unusual places – in the brain and visceral veins. This applies not only to the AstraZeneka and Johnson & Johnson vaccines. Very rare cases have also been reported after the administration of Pfizer and Moderna preparations.

1. Last week, the European Medicines Agency (EMA) issued a communication regarding the link between AstraZeneki and thrombosis. Disease is a very rare side effect after administration of the preparation
2. On Tuesday, the US FDA and CDC called for the suspension of vaccination with Johnson & Johnson in the US. After its use, there were 6 cases of thrombosis in women
3. Thrombosis has also occurred following the administration of the Pfizer and Moderna vaccines
4. You can find more such stories on the TvoiLokony home page

Cerebral vein sinus thrombosis (CVST) – what is it?

In a healthy organism, blood flows freely through blood vessels, oxygenating individual organs. Thrombosis occurs when this free blood flow is blocked. This happens when platelets stick to the endothelium to form a clot. When this happens, the vein can become clogged – blood cannot flow freely.

Cerebral venous sinus thrombosis (CVST) occurs when this blockage occurs in a large vein in the brain. The formation of a blood clot in this area can lead to hypoxia and disruption of the nervous system.

Thrombosis following COVID-19 vaccines

Last week, the European Medicines Agency issued a communication about the very rare cases of thrombosis in people who received AstraZeneki. The EMA acknowledged that this could be a side effect of using an anti-COVID-19 preparation. At the same time, the agency assured that thrombosis is extremely rare, and that the benefits of using the AstraZeneki vaccine outweigh the potential risks.

In turn, on Tuesday, the US Food and Drug Administration (FDA) together with the Centers for Disease Control (CDC, a leading global organization fighting epidemics) called for the suspension of vaccination with Johnson & Johnson in the US. This is because of the subsequent cases of thrombosis in people who received the vaccine. So far, there are six cases, all of which affect women between 18 and 48 years of age. They developed thrombosis 6 to 13 days after receiving Johnson & Johnson.

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The data correspond to those for the AstraZeneki vaccine. There, blood clots were more common in women under the age of 60. Symptoms lasted up to 14 days after vaccination (other sources said it could be up to 21 days). However, thrombosis has also been reported after the Pfizer or Moderna vaccine.

– According to the EMA, 35 cases of cerebral venous thrombosis have been reported for the Pfizer vaccine per 54 million doses administered. In the case of the Moderna vaccine, this is 5 cases out of 4 million vaccinations – said Dr. Bartosz Hudzik, MD, specialist in internal medicine and cardiologist.

Dr hab. Hudzik also noted the location of blood clots that appear after COVID-19 vaccination. They mainly occur in the venous sinuses of the brain and visceral veins. In these locations, the disease is very rare in the general population, but after vaccination it affects all the above-mentioned preparations.

– Thrombosis in atypical places, such as the portal vein, the retinal vein or the central artery of the retina, outside of vaccinations, most often occurs in people with congenital or acquired thrombophilias. HIT itself (heparin thrombocytopenia) is also thrombophilia. It all adds up and explains the mechanism to some extent – explained Dr. Hudzik.

Where does thrombosis come from after the COVID-19 vaccine?

Thrombosis can occur in different places. There are, among others, thrombosis of the veins of the lower extremities, pulmonary embolism, thrombosis of the visceral veins or the sinuses of the cerebral veins. After vaccination against COVID-19, the last two are primarily noted.

– EMA at the conference on April 7 reported that 22 cases of thrombosis were diagnosed on March 86, of which 62 cases concerned venous sinus thrombosis of the brain, and 24 – visceral vein thrombosis – quoted Dr. Hudzik. – Of these 86 cases, 18 were fatal. In turn, the analysis carried out on April 4 shows that 169 cases of thrombosis of the venous sinuses of the brain and 53 cases of thrombosis of visceral veins were identified in the European Union and the United Kingdom. This is roughly equivalent to 1 in 1 million people vaccinated. It is estimated that, depending on the country, this rate varies from 4 to 10 cases per 1 million people vaccinated.

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At the moment, it is not certain why COVID-19 vaccines cause thrombosis, but scientists see a pattern here.

– We already have some clues about what can cause a thrombotic event after receiving the AstraZeneki vaccine. It turned out that in some patients with thrombosis in atypical location, thrombocytopenia was also observed. In the general population, thrombocytopenia is most commonly associated with a bleeding tendency. After vaccination, we are dealing with thrombocytopenia and thrombosis. A similar mechanism is sometimes observed in patients given heparin – an anticoagulant drug (heparin-induced thrombocytopenia – HIT). When the patient’s body begins to produce antibodies against the combination of heparin and platelet factor, thrombocytopenia, platelet activation and thrombosis also occur – explained Dr. Hudzik.

Symptoms of thrombosis after vaccination for COVID-19. This is what you need to pay attention to

EMA and the Polish Society of Hematologists and Transfusion Medicine have developed a list of symptoms that may indicate thrombosis after receiving the COVID-19 vaccine. They include:

1. shortness of breath or shortness of breath
2. chest pain
3. swelling or asymmetrical pain in the leg
4. persistent abdominal pain
5. neurological symptoms, including severe and persistent headaches, blurred vision, and seizures
6. small spots of blood under the skin other than where the injection is given

These symptoms could indicate a different location for the clot.

– The symptoms listed by the EMA indicate three areas of thrombosis. Headache, blurred vision and convulsions is a possible symptom of cerebral venous sinus thrombosis. Persistent abdominal pain indicates thrombosis of the visceral veins. Shortness of breath and chest pain is a symptom of a pulmonary embolism. All these conditions can be life-threatening. On the other hand swelling of the leg (possibly accompanied by leg pain) may indicate lower limb venous thrombosis, which may also lead to pulmonary embolism. These symptoms need attention, and not only after the AstraZeneki vaccine.

The cardiologist emphasized that in the event of symptoms, a quick reaction on the part of the patient is necessary.

– The longer the delay after the onset of symptoms, the worse the condition the patient can go to hospital. This, in turn, reduces the chances of healing him and saving his life. Experts of the Polish Society of Hematologists and Transfusion Medicine have also prepared a diagnostic and therapeutic algorithm for these patients.

Also read:

1. “Am I to receive the sick and put them on the blankets on the floor?”. A doctor about the situation in the “non-covid” ward
2. New question in the pre-vaccination questionnaire for COVID-19. Binds to AstraZeneka
3. These drugs can reduce the effectiveness of COVID-19 vaccines
4. Cardiologist about the AstraZeneki vaccine. Who shouldn’t take and why are blood clots more common in women?

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