An adverse event after the administration of a vaccine does not imply that the drug is the cause, but it must always be studied.

Image of the Interterritorial Council of this Monday in which it has been decided to stop the vaccination with AstraZeneca.

This weekend took place in Spain a case of cerebral venous sinus thrombosis in a patient who had received the coronavirus vaccine developed by the AstraZeneca company, as reported this Monday by the director of the Spanish Medicines Agency, María Jesús Lamas.

This fact, and after learning that similar cases have also been detected in Norway and Germany, in total 11 cases, is the reason given by the Ministry for deciding temporarily and cautiously suspend the administration of this vaccine, until the Pharmacovigilance Risk Assessment Committee (PRAC) of the European Medicines Agency (EMA) issues a detailed assessment of all cases, which is expected to it happens this thursday.

However, as explained in this article by The Conversation, “When such a large number of people are vaccinated in a short period of time, including groups of patients at risk of certain diseases, it is unavoidable to observe a high number of adverse events without this meaning that they are due to the vaccine ”.

The author continues contextualizing: “As explained by the AEMPS, an adverse event is any undesirable event experienced by a patient, regardless of whether or not the drug administered is suspected. An example of an adverse event is a patient who suffers a traffic accident while on a specific drug treatment. On the other hand, an adverse reaction (ADR) is any undesirable event that has happened with the patient while he was using a medicine and there is a suspicion that it is caused by the medicine ”.

The text adds that until March 10 they had been notified thirty cases of thromboembolic events among about five million people vaccinated with the AstraZeneca vaccine in the European Union.

The number of thromboembolic events in vaccinated people would be within expected. That is, it is not greater than the number observed in the general population, since only pulmonary thromboembolism an annual incidence is estimated between 70 and 113 cases per 100,000 people of any age in the general population.

In Spain, in 2018, there were 11 hospital admissions for every 100,000 inhabitants aged 35 to 39 years for pulmonary embolism. This figure increases to 82 cases per 100,000 people aged 65 to 69 and is higher in older people.

Beyond the fact that everything indicates that the vaccine will not be behind the episode suffered by a Spanish vaccinated, Lamas spoke of a specific type of thrombosis, that of cerebral venous sinuses. Do youWhat is this neurological condition??

According to the Spanish Society of Neurology, thrombosis is any situation in which the patient has a thrombus or a blood clot that prevents or hinders blood circulation. And in the case of cerebral venous sinus thrombosis, it is so named because this thrombus is located in the venous system of the brain.

Cerebral venous sinus thrombosis is a rare cerebrovascular disease (It represents less than 0.5% of the total cases of cerebrovascular diseases that occur in Spain). Its incidence is considered to be around 1 – 1.3 cases / 100. 000 inhabitants per year.

It can affect any age group, although it is slightly more common in women and young patients. Among the sex-specific risk factors are oral contraceptives, pregnancy, and the use of hormonal therapies. Diagnosis is made by neuroimaging tests (CT and Magnetic Resonance).

“The most frequent symptom of cerebral venous sinus thrombosis is headache, a symptom that occurs in nine out of ten people suffering from cerebral venous sinus thrombosis. But also, in the vast majority of patients, this headache is accompanied by other stroke-like symptoms (such as focal deficits, loss of strength or sustained sensitivity, gait disturbance or language or speech disturbance, confusional episodes, loss of vision,…) that helps to differentiate this headache from a conventional headache. It can also be accompanied by other symptoms such as vomiting, epileptic seizures, or cervical stiffness ”, explains José Miguel Láinez, President of the Spanish Society of Neurology.

In any case, the headache caused by a cerebral venous sinus thrombosis is very characteristic: it may have a sudden onset, may be located on one side of the head only, worsens when the patient is lying down or exercising, interrupts the night’s rest and, in addition to not responding to the usual treatments for headache, it progressively worsens.

As with all cerebrovascular diseases, it involves a neurological emergencyTherefore, the sooner the patient is treated, the fewer the consequences. The treatment of choice is usually antithrombotic drugs, although in more severe cases, endovascular thrombectomy and thrombolysis are also very useful options for removing the thrombus.

“Generally and, especially if it is treated in time, patients suffering from cerebral venous sinus thrombosis have a favorable prognosis. Only in severe cases where treatment is delayed can it lead to disability or a fatal outcome. In addition, in recent years, thanks also in part to the fact that most cases of cerebral venous sinus thrombosis reach hospitals through the Stroke Code, the speed in the care of these patients is increasingly rapid and the prognosis This disease is becoming more favorable ”, highlights Dr. José Miguel Láinez.

In Spain, recovery after cerebral venous sinus thrombosis is complete in approximately 80% of patients and only 5% develop some type of severe sequel. Therefore, the prognosis of this disease is much more favorable than in other types of cerebrovascular diseases.