Vasovagal reaction: A reflex of the involuntary nervous system that causes the heart to slow down (bradycardia) and that, at the same time, affects the nerves to the blood vessels in the legs permitting those vessels to dilate (widen). As a result the heart puts out less blood, the blood pressure drops, and what blood is circulating tends to go into the legs rather than to the head. The brain is deprived of oxygen and the fainting episode occurs. The resultant fainting is synonymous with situational syncope (pronounced sin-ko-pea)...I saw one of these reactions today - in my youngest son. It scared the h*ll out of me. We'd received a note from his school advising us that he needed his Measle/Mump/Rubella booster. (He's 16 - apparently you need to get them from time to get even after they're babies.) So today I'd taken him to the doctor to get that done, as well as our annual flu shots. The doctor did all the usual check ups - height (6'1"), weight (137 lbs - wow I'm jealous), everything appeared fine.
Time for the 'situation' that caused the syncope. The shot.
Now Curly is not afraid of needles - we've had flu shots every year since he was little, he had his HepB shots in grade 7 ... it's never bothered him, he's never had a reaction. He didn't appear nervous, shrugs off any questions regarding anxiety - even now.
The doctor gave him the shot, asked if that hurt ... "nope, not at all," answered Curly with a grin. Two minutes later he's pale, sweating and announcing he's not feeling well, that he's going to be sick. The doctor rushed over to him, told him to lie down but before he can move, Curly slumps in the chair.
Now, all those stories I've read that tell of eyes rolling up in the head when someone faints? Or eyelids fluttering closed? Nope, that didn't happen. What I did see was this blank dead stare - like the stereotypical 'light went off but nobody's home' cliche, and his eyes stayed open the whole time. It was eerie as heck. And as his mother, absolutely frightening.
The doctor tipped the chair over so Curly was lying down. And then Curly jerked like he was having a mini-seizure (This I've seen before when Curly went into convulsions when he was in grade 5 as a reaction to a medication, but I'm not sure if it was a true seizure today or just the blood getting back to the brain and the synapses firing up.)
Less than a minute later, that 'light' came back into his eyes like someone had flicked a switch. He stared up at me. And started giggling.
He says he doesn't remember that - I figure it was the lightheadedness that was doing it. We spent the next half hour with him lying down in an examination room, and the doctor giving him milk and cookies to bring his blood pressure back up. For scientific/writing purposes, a good blood pressure is 120 (systolic) over 80 (diastolic). [the systolic rate (the higher number) is the force the heart uses to pump the blood through the arteries, the diastolic (lower number) is the resting rate.] Curly's systolic after he regained consciousness was less than 80 so the doctor wouldn't let him leave until his systolic reached 115.
How is he now? Just fine, though embarrassed. I've told him not to be, but try telling that to a 16 year old who's just found himself flat on the floor in a doctor's office. Yeah, I probably would be too.
But the awful part of it was that the whole time it was going on, a part of my brain was thinking "I've got to remember this so if I ever have to write about someone fainting ..."