Syncope is extremely common occurring in about 30% of patients at some point in their lives. About 37% of patients who faint will suffer injury. About 75% of non- elderly adults who faint do so in the absence of an associated medical problem.
Any person who faints should seek medical attention.
Neurocardiogenic syncope - the “common faint” - also is called “vasovagal syncope.” It usually (but not always) occurs when a person who is lying or sitting down moves to a standing position.
From 25 percent to 40 percent of fainting disorders are due to neurocardiogenic syncope. Classically, patients with neurocardiogenic syncope or NCS, experience weakness, fatigue, pallor, sweats often described as cold sweats, nausea and a sensation of impending doom (feel like you are going to die). The episode is usually self- limited and after it passes you may be let feeling weak.
Conditions that may cause or increase the likelihood of a faint are pain, sleepiness, hunger pangs, defecation, urination, blood drawing, and prolonged standing particularly in the heat.
This type of syncope often affects young, healthy people who have no history of heart disease or neurological problems. Frequently it is seen in families. It is generally thought to result from a exaggeration of a normal reflex.
When we stand up, our brains send signals telling the blood vessels in our legs to dilate, or open wider. Often, a signal also is sent that slows the heartbeat. When the blood vessels suddenly dilate, blood may pool in the legs so that a normal volume of blood does not return to the heart. If the heart does not pump enough blood to supply the brain’s need for oxygen, we become lightheaded or faint.
Sometimes, the heart tries to raise the blood pressure by increasing the force and rate of its muscle contractions. This makes the problem worse:
As the heart beats faster and stronger, it sends a wrong message that tells receptors in the heart’s chambers that the ventricle is filled with blood.
The rereceptors send a message telling the nervous system that blood pressure is too high. In fact, the ventricle is not full and the blood pressure is too low.
When the brain receives the faulty message, it slows the heart rate and further dilates the blood vessels.
The blood pressure drops even lower, less blood is pumped to the brain and the risk of fainting increases.
Neurocardiogenic syncope is the most common cause of fainting in young people. Some adolescents have frequent fainting spells, but many cardiologists who treat syncope report that most of their young patients have “grown out” of the condition by the time they reach their mid-twenties.
The diagnosis is commonly made on the basis of the clinical history. If the diagnosis is unclear, or the risk of a recurrent attack places the patient at increased risk of injury, a test known as a HUT or head up tilt table test is done to either establish the diagnosis or assess the adequacy of treatment.
Treatment of NCS is to avoid the precipitating cause, such as dehydration, pain, lack of sleep or a combination of these. Patients who continue to have symptoms or loose consciousness despite avoiding noxious stimuli are treated by a variety of measure including salt loading, medications called beta blockers or SSRI’s (medications used to treat depression). Additionally, a medication called midrodine is occasionally used. Maneuvers such as “body compression” can be taught by your physician to terminate or decrease the severity of attacks. Orthostatic training can also be taught to the patient to decondition the response and avoid episodes. In rare instances insertion of a pacemaker is used in addition to medications to treat extreme cases.
Patients can be reassured that this is a benign condition that while very unpleasant, is rarely serious.
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