Fainting - Syncope Introduction Fainting, also known as syncope, is a temporary loss of consciousness. It is caused by a drop in blood flow to the brain. You may feel dizzy, lightheaded or nauseous before you faint. A person who has fainted usually regains consciousness in a few minutes and completely recovers. Fainting is usually nothing to worry about. But it can sometimes be a sign of a serious problem. If you faint, it is important to see your health care provider and find out why it happened. This reference summary explains fainting. It discusses the causes and treatment options for the condition. Fainting Fainting is a temporary loss of consciousness. If you are about to faint: You may feel dizzy, lightheaded or nauseous. Your field of vision may "white out" or "black out." Your skin may feel cold and clammy. You lose muscle control and you may fall down. A person who faints usually regains consciousness and alertness in a few minutes. Fainting usually happens when your blood pressure drops suddenly. This causes a decrease in blood flow to your brain. It is more common in older people. 1
Some causes of fainting include: Certain medicines. Drop in blood sugar. Emotional distress. Heart problems. Heat or dehydration. Standing up too quickly. About a third of people faint at least once during their lifetime. Many people never faint again after the first time. Fainting is usually nothing to worry about. But if you faint, it is important to see your health care provider and find out why it happened. Sometimes fainting can be a sign of a serious problem. Types of Fainting There are several types of fainting: Vasovagal syncope. Situational syncope. Postural syncope. Cardiac syncope. Neurologic syncope. Psychogenic syncope. Each of these types has different causes and symptoms. Vasovagal syncope is also known as the common faint. It is the most frequent cause of syncope. Vasovagal syncope happens when your heart pumps more forcefully and your blood vessels relax. But your heart rate does not keep up with the blood flow needs of the brain. Causes of vasovagal syncope include: Environmental factors, such as a hot or crowded setting. Emotional factors, such as stress or the sight or threat of injury. Illness, such as fatigue or dehydration. Physical factors, such as standing too long. 2
Vasovagal syncope causes a person to feel lightheaded and shaky. Their vision may be blurred, or they may see spots in front of their eyes. Other signs of vasovagal syncope include: Dilated pupils. Paleness. Sweating. While unconscious, a person experiencing vasovagal syncope also may have a low pulse rate. They should regain consciousness quickly. Situational syncope is a type of vasovagal syncope. It happens only in certain situations. Cough syncope is fainting that happens during intense coughing. Swallow syncope is fainting that can happen during swallowing if you have a throat or esophageal disease. Micturition syncope is fainting that happens after a person urinates. Carotid sinus hypersensitivity is fainting that happens when you turn your neck, shave or wear a tight collar. The carotid sinus is a cluster of nerves very close to the carotid artery in the neck. Postprandial fainting can happen in elderly people when their blood pressure falls about an hour after eating. Postural syncope happens when a person suddenly faints when they stand up after lying down because of a temporary decrease of blood flow. This sometimes happens in people who have recently started or changed certain cardiovascular medicines. Postural syncope can be caused by low circulating blood volume. This can be due to: Blood loss. Dehydration. Heat exhaustion. 3
Postural syncope can also be caused by impaired circulatory reflexes due to: Congenital problems. Congenital problems mean problems that have been present since birth. Medicines. Problems with the nervous system. Signs and symptoms of postural syncope include: Blood loss, such as a heavy menstrual period or blood in the stool. Dry lips and tongue. Lightheadedness. Paleness and sweating. Vomiting, diarrhea and fever. Heart disease can cause a person to faint. This is known as cardiac syncope. It can be life-threatening and may happen without warning. Cardiac syncope could be caused by: Arrhythmia, an abnormal heart rhythm. Heart disease. Heart failure. Heart valve problems. Symptoms of cardiac syncope include: A weak pulse. Chest pain. Paleness and sweating. Palpitations, which are pounding, fast or abnormal heart beats. Shortness of breath. Neurologic syncope can be caused by: Migraines. Seizures. Stroke. Transient ischemic attack, also known as TIA, or mini-stroke. 4
Seizures are a cause of unconsciousness but are different from fainting. With seizures, the blood flow to the brain does not decrease. Unconsciousness results from disordered electrical discharges within the brain. Symptoms of neurologic syncope include: A headache. Double vision. Loss of balance. Slurred speech. Vertigo, which is the feeling that the room is spinning. Hyperventilation from an anxiety disorder can also cause fainting. This is known as psychogenic syncope. Self Care At Home When someone faints, try to help them lay down gently on the ground. Try to wake the person up by yelling their name or tapping them on the shoulder. Call for medical help right away if they do not respond. Make sure that his or her airway is clear. Check to make sure they are breathing. Check for a pulse and perform CPR if needed. When a person who has fainted revives, ask them if they have: Abdominal pain. Back pain. Chest pain. Headache. Shortness of breath. Weakness or loss of function. These symptoms may mean that the cause of the fainting is life-threatening. Most people recover completely after fainting. Fainting is usually nothing to worry about. But it can sometimes be a sign of a serious problem. If you faint, it is important to see your health care provider and find out why it happened. 5
Diagnosis and Treatment The exact cause of fainting is determined in only about 60% of cases. To diagnose the cause, your health care provider will perform a physical exam. He or she will ask questions about your personal and family medical history. The treatment of fainting depends on the diagnosis. Most types of fainting do not require medical treatment. After fainting, you should: Sit up slowly and gradually and gently stretch for a few minutes. Drink plenty of water. Increase your salt intake. Avoid standing for too long. Medicines that cause fainting can be changed. The treatment for cardiac syncope is specific to the underlying illness. Heart disease often requires surgery, while an arrhythmia might require medicines, lifestyle changes or a pacemaker. If a cardiac cause is suspected, several tests are available. They are used to identify heart problems that can cause fainting. If the cause of fainting is not determined and the affected person is not hospitalized, he or she should see a health care provider within a few days. Prevention Fainting can sometimes be prevented by taking simple steps. To prevent fainting, avoid fainting triggers. If you faint in hot or crowded rooms, avoid these places when possible. If you faint while standing up from a lying down position, take care to move slowly when standing up. Move slowly to a sitting position and rest a few minutes. When you are ready, stand up slowly. Elderly people with low blood pressure after eating should avoid large meals or plan to lie down for a few hours after eating. This can prevent postural syncope. Cardiac syncope can cause death. People who experience cardiac syncope may be able to control the condition through diet and medicines. 6
Ask your health care provider if it is okay for you to drive. Depending on where you live, it may be illegal to drive if you have a history of fainting. Summary Fainting, also known as syncope, is a temporary loss of consciousness. It is caused by a drop in blood flow to the brain. You may feel dizzy, lightheaded or nauseous before you faint. A person who faints usually regains consciousness and alertness in a few minutes. Fainting usually happens when your blood pressure drops suddenly. This causes a decrease in blood flow to your brain. It is more common in older people. Some causes of fainting include: Certain medicines. Drop in blood sugar. Emotional distress. Heart problems. Heat or dehydration. Standing up too quickly. About a third of people faint at least once during their lifetime. Many people never faint again after the first time. When someone faints, try to help them lay down gently on the ground. Try to wake the person up by yelling their name or tapping them on the shoulder. Call for medical help right away if they do not respond. After fainting, you should: Sit up and gently stretch for a few minutes. Drink plenty of water. Increase your salt intake. Avoid standing for too long. Fainting can sometimes be prevented by taking simple steps. To prevent fainting, avoid fainting triggers. 7