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Fainting, also called syncope or passing out, is a symptom that occurs when there is inadequate blood flow to the brain. It is temporary, with a loss of consciousness that comes on quickly and can lead to falling. In true syncope, recovery is prompt and complete.
It is generally an uncommon occurrence for most people and for the most part, is not a sign of serious illness. But in some people, fainting can be the first and only sign before sudden cardiac death.
Unconsciousness due to seizures, heart attacks, head injury, stroke, intoxication, a blow to the head, diabetic hypoglycemia, or other emergency condition is not considered syncope.
The most common causes of fainting include:
- Reflex syncope (also called neurally mediated syncope, vasovagal syncope, vasodepressor syncope, the common faint)
- The most frequent cause of fainting
- Results from a reflex response to some trigger
- The heart slows or blood vessels dilate (widen) and blood pressure drops, so less blood flows to the brain and fainting (syncope) or near-fainting (pre-syncope) occurs
- Triggers for vasovagal syncope can include:
- Other types of reflex syncope include
- Situational syncope, a sudden reflex response to a trigger other than those listed above
- Triggers include:
- Coughing, sneezing, laughing, swallowing
- Eating a meal
- Sudden abdominal pain
- Defecating
- Urinating (post-micturition syncope: occurs in men while standing to urinate)
- Pressure on the chest after exertion or exercise
- Playing a brass instrument
- Weight lifting
- Carotid sinus syncope
- Occurs in older people when pressure is applied to the carotid artery in the neck such as by a hard twist of the neck, wearing a tight collar, and pressing on the artery
- Serious cardiovascular conditions (cardiac syncope), which may be caused by:
- Irregular heartbeat (arrhythmia) and abnormal heart rhythm
- Aortic dissection, a tear in the aorta; very rare but life-threatening
- Aortic valve stenosis, a narrowing of the valve between the heart and the aorta
- Orthostatic hypotension (low blood pressure when standing)
- A drop in systolic blood pressure (the top number) of 20 mmg Hg or more on standing
- Postural Orthostatic Tachycardia Syndrome (POTS) (increased heart rate when standing)
- Characterized by an increase in heart rate of at least 30 beats per minute on standing and orthostatic intolerance
- Rare, and occurs more often in young women
What Are Symptoms of Fainting (Syncope)?
Fainting (syncope) is a symptom of another condition, and characteristics may include:
- Lightheadedness
- Pale face
- Increased anxiety and restlessness
- Sweating
- Nausea
- Weakness
- Visual “gray out”
- Trouble hearing
- Collapse
- Unconsciousness/passing out for a few seconds
- Full recovery after a few minutes
See a doctor immediately if the above symptoms are accompanied by:
- Shortness of breath
- Chest pains
- Heart palpitations
- The pulse is faster or slower than expected
- Slurred speech
- Facial droop
- Weakness in any limbs
These may be signs of serious medical conditions such as heart problems or stroke.
How Is Fainting Syncope Diagnosed?
The cause of fainting (syncope) is diagnosed with a patient history and physical examination, and tests such as:
- Electrocardiogram (ECG or EKG)
- Exercise stress test
- Echocardiogram or transesophageal echocardiogram (ultrasound of the heart)
- Tilt table test
- Electrophysiology study (EP)
- In-home diagnostic monitors
- Holter monitor: a portable ECG worn continuously for one to seven days to record heart rhythms over time
- Event monitor: a portable ECG worn for one or two months that records only when triggered by an abnormal heart rhythm or manually activated
What Is the Treatment for Syncope?
If you feel faint, lie down and elevate your feet, if possible, to try to prevent loss of consciousness.
If fainting occurs, remain lying down for ten minutes and then sit up slowly.
First aid treatment for a person who has fainted includes:
- Help the person lie down
- If the person is unconscious, roll them on their side
- Check if they are breathing and they have a pulse
- Elevate the feet above the height of the head if possible
- If fainting occurred due to heat, remove or loosen clothes, and try to cool the person down by wiping them with a wet cloth or fanning them
- Check if the person was injured if they fell when they passed out
- In an emergency, call 911 if the person has not regained consciousness within a few seconds or recovered in a few minutes
Treatment for fainting (syncope) depends on the underlying cause and may include:
- Catheter ablation
- Pacemaker
- Implantable cardioverter-defibrillator (ICD)
- Avoiding known triggers
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https://www.hopkinsmedicine.org/health/conditions-and-diseases/syncope-fainting
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/fainting
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767616/