It may result in a bit of a tremble or shake. Sometimes it looks like a shudder; sometimes it looks like a seizure albeit very short. Ever felt an involuntary jerk in your arms or legs just as you fall asleep? That is called a myoclonic contraction, and it's exactly the same type of twitch some fainting patients exhibit. While a myoclonic contraction is not a seizure, true seizures can also cause a sudden loss of consciousness.
Once the person goes from vertical to horizontal, blood starts flowing back into the brain and they begin to wake up. It can be quick or it can take a while; everybody's different. Some of the more common symptoms that can occur after fainting:.
Most fainting is triggered by the vagus nerve. When food enters the system, the vagus nerve directs blood to the stomach and intestines, pulling it from other body tissues, including the brain. Unfortunately, the vagus nerve can get a little too excited and pull too much blood from the brain. Some things make it work harder, such as bearing down to have a bowel movement or vomiting.
Medical conditions that drop blood pressure amplify the effects of the vagus nerve—even extreme pain from menstrual cramps. Too little water in the bloodstream lowers blood pressure, and stimulating the vagus nerve when the system is already low can lead to dizziness and fainting.
There are many causes of dehydration—vomiting or diarrhea , heat exhaustion , burns, and more. Vomiting and diarrhea, specifically, also stimulate the vagus nerve. Not all losses of consciousness are related to the vagus nerve.
Shock is a condition characterized by low blood pressure that often leads to a loss of consciousness. As a society, we are very aware of the long-term consequences of high blood pressure , but very low blood pressure is much more immediately dangerous.
Shock is a life-threatening emergency that usually comes from bleeding, but can also come from severe allergy anaphylaxis or severe infection. People with shock will most likely become confused, then lose consciousness as their condition gets worse. It can all happen very quickly, and although it's not fainting, per se, we can't really tell unless the patient wakes up. Taking a wait-and-see attitude may be dangerous.
Plenty of people lose consciousness due to alcohol use, and we don't call it fainting although passing out still seems appropriate. Besides its obvious sedation effect, alcohol makes you urinate, which will eventually lead to dehydration. It also dilates blood vessels, which decreases blood pressure. Like shock, losing consciousness due to alcohol is not technically considered fainting, but it may or may not be cause for concern.
It is possible to die from alcohol poisoning , and passing out is a sign of serious intoxication. Other drugs—legal as well as illegal—can knock you out for a variety of reasons:. Your heart is the pump that forces blood through your veins and arteries.
It takes a certain amount of pressure in the bloodstream to keep it flowing. A correctly functioning heart is essential to maintaining adequate blood pressure. If the heart beats too fast or too slow, it can't keep the blood pressure up as high as it needs to be.
Fainting often results when blood flow to the brain is temporarily inadequate. This can happen as a result of stress, grief, overheating, dehydration, exhaustion, or illness; fainting may also occur after taking certain medications. Standing for an extended period in very hot weather -- especially with locked knees -- can also make people pass out.
Inactivity can cause blood to settle in the lower parts of the body, reducing the amount of blood flowing into the brain. Soldiers standing at attention for long periods are prone to fainting, for example. Certain medications can lower blood pressure to a level that will trigger fainting. People with diabetes can sometimes lose consciousness if their blood sugar levels are too high or too low. Many people recover very quickly from a brief loss of consciousness without any harmful consequences.
However, on some occasions, fainting can signal a medical emergency. Don't treat fainting as minor unless you're certain there is no serious underlying cause. When these signs appear, it is important to lie down or to sit down and put your head between your legs. That's usually enough to restore adequate blood flow to the brain. If it is very hot, try to move to a cooler location. Loss of consciousness that lasts for more than a minute or two can be serious, however.
Often it is a sign of a serious medical problem, such as seizure, serious blow to the head, concussion, heart attack, diabetic coma, epilepsy, or another condition.
It is important to treat someone who has fainted or lost consciousness with care to avoid injury. If someone remains unconscious for more than a minute, get help as quickly as possible. If you suspect that the cause is excessive heat, move the person to a cooler place. Lay the person on her back, elevating the legs eight to 12 inches. This usually refers to a trauma, pain, emotional stress, or seeing something disturbing like when people pass out if they see blood.
You've seen those videos of groomsmen falling over during wedding ceremonies because they are locking their knees? That's a vasovagal cause of syncope. This can sometimes be a dangerous one - you ever get to the point when you are working outside or exercising in the heat, and you start seeing those dots floating around? You're dehydrated, and you've gotten too hot. If you don't stop, cool off, and drink a good bit of water and keep going, you're very likely to pass out.
High blood pressure medicines that dilate blood vessels or affect the rate the heart pumps blood - if they limit blood flow too much, there's that possibility where not enough will get to the brain every once in awhile. If it doesn't beat often enough, or maybe beats fast but weakly.
Heart block, supraventricular tachycardias, ventricular tachycardias are examples of an irregular heartbeat. Warning signs of syncope:. There can be a few symptoms prior to a spell of syncope. And remember what's going on here - your brain isn't getting enough blood, so it's struggling. The brain is the command center of your body, and when it struggles, things start to go on the fritz. We have received your information. Check your inbox, in a few moments you will receive a confirmation email.
Accept cookies. This link opens in a new tab. Loss of Consciousness Causes. What is it? Joint project with. Causes a Loss of Consciousness Reading time: 2 min. Non-cardiac causes. A migraine attack. The lowering of sugar in the blood, or hypoglycaemia.
Alcohol consumption and abuse of other drugs. Cardiac causes.
0コメント