What happens in our body during an anaphylactic shock?
How many stories have we heard from people who suddenly developed allergies to something they had never had before? Or allergic reactions so severe that they made the patient stop in the hospital? How does all this happen, and what is this anaphylactic shock about?
Well, do you remember the antigens, T lymphocytes and lymph nodes from the time of biology classes? These are the elements involved in the body's response to foreign bodies, which leads to an eventual allergic reaction.
The allergic reaction
When they identify an antigen, that is, an agent foreign to the body, immune cells communicate with T lymphocytes located in the lymph nodes, creating a kind of warning to the body that something different is happening.
This causes the T lymphocytes to prepare a cell called TH2, capable of releasing interleukins, which are the body's first major defense. They produce antibodies that function to attach to the mast cells and release a fighting substance next to the antigens. Another function of interleukins is to activate eosinophils, the white blood cell that triggers toxic substances to destroy antigens.
It's a process similar to a video game: when you see an enemy coming, plant a mine and shoot it until you destroy it. With cells, however, the process is so sophisticated that they can know if the type of antigen is resistant to this attack and change the procedure so that from that attempt it can be labeled as an allergen - something the body reads as being a more powerful enemy.
From the moment this happens, however, the body is constantly on the alert to combat this element and, at the slightest sign of entry, begins to react. This is what explains the allergies that appear only when we are adults.
According to Stanford University researcher Tina Sindher, the allergic reaction is nothing more than a mast cell releasing inflammatory mediators composed of substances such as histamine and interlucines.
From there, it is a feast of released substances, with activation of more eosinophils, more TH2 cells and basophilic white blood cells, and leukotrienes, which are responsible for accelerating the reaction and displacing more cells from the immune system to the region. This all generates beneficial inflammation aimed at preventing possible infection, but does not mean that the whole process is not painful for the body.
Thanks to the release of histamine, blood vessels dilate, the bronchi contract, and blood flows better through the spaces between cells, but this causes swelling and itching in a process that lasts for several hours, usually between 8 and 12.
If a person has a more severe allergy, however, all of this can be more intense. In this case, if the bronchi contract too much and the vessels dilate inappropriately, blood pressure drops and the heart does not access enough blood, which prevents the organs from receiving the oxygen they need. This is how the body goes into anaphylactic shock.
To counteract the reaction, an injection of epinephrine, which contains adrenaline, the hormone of the adrenal glands that helps to constrict blood vessels, is needed. At this point, the reaction can occur in minutes, and an antihistamine no longer solves the problem.
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