How to diagnose syncope(faint)?

Question

I know that syncope can happen because of various factors but is there a way to clarify the causes of faint?

And why someone standing under the scorching sun for a while tends to faint?

Can someone explain how decrease in blood glucose will lead to faint?

Answer 1

Here's a full description of the condition, sources and treatments.

http://www.annals.org/cgi/content/full/126/12/989


More info:
http://www.wrongdiagnosis.com/s/syncope/misdiag.htm

Answer 2

To be honest, you can't diagnose a syncopal episode in the field because you can't perform and electroencephlogram to determine this diagnosis. Because someone blacks out doesn't rule out a possible hemorrahgic stroke or acute seizure activity.

The sun dehydrates the human body of its electrolytes. Without these fluids, the body can't maintain its core temperature of 37 degrees. If our bodies get to hyperthermic, the heat can begin to denature the protein in out body which unravels the hemoglobin in our body. Therefore, the hemoglobin can't carry oxygen to the body tissues and the person becomes hypoxic.

Glucose, next to fat, is the number one source of energy used by the body. Glucose is what produces ATP and allows our body to function. Fainting is a exaggerated immune response to shut down the body as to conserve energy while it tries to remedy the situation.

Answer 3

heat syncope is because of dehydration and vasodilatation of the blood vessels because of heat, causing reduced cerebral perfusion - and thus fainting

hypoglycaemia causes reduced substrate for the brain to metabolise and cells shut down, again causing fainting

Answer 4

Urrrrrrrrrr Umm when somebody drops??!!

Answer 5

Definition of Fainting (syncope)

Fainting (syncope): Partial or complete loss of consciousness with interruption of awareness of oneself and ones surroundings. When the loss of consciousness is temporary and there is spontaneous recovery, it is referred to as syncope or, in nonmedical quarters, fainting. Syncope accounts for one in every 30 visits to an emergency room. It is pronounced sin-ko-pea.

Syncope is due to a temporary reduction in blood flow and therefore a shortage of oxygen to the brain. This leads to lightheadedness or a "black out" episode, a loss of consciousness. Temporary impairment of the blood supply to the brain can be caused by heart conditions and by conditions that do not directly involve the heart:

Non-cardiac causes: Syncope is most commonly caused by conditions that do not directly involve the heart. These conditions include:

Postural (orthostatic) hypotension: Drop in blood pressure due to changing body position to a more vertical position after lying or sitting;
Dehydration causing a decrease in blood volume.
Blood pressure medications leading to low blood pressure.
Diseases of the nerves to the legs in older people (especially with diabetes or Parkinson's disease) when poor tone of the nerves of the legs draws blood into the legs from the brain.
High altitude.
Brain stroke or "near-stroke" (transient ischemic attack).
A migraine attack.
Fainting after certain situations (situational syncope) such as:
Blood drawing,
Urinating (micturition syncope),
Defecating (defecation syncope),
Swallowing (swallowing syncope), or
Coughing (cough syncope)
that trigger a reflex of the involuntary nervous system (the vasovagal reaction) that slows the heart and dilates blood vessels in the legs and cause one to feel nausea, sweating, or weakness just before losing fainting.
Cardiac causes: Heart conditions that can cause syncope or fainting due to temporary loss of consciousness include:

Abnormal heart rhythms (heart beating too fast or too slow).
Abnormalities of the heart valves (aortic stenosis or pulmonic valve stenosis).
High blood pressure in the arteries supplying the lungs (pulmonary artery hypertension).
Tears in the aorta (aortic dissection).
Widespread disease of the heart muscle (cardiomyopathy).
To be sure, many of the causes of temporary loss of consciousness can be detected by a careful history. Dizziness after standing up in an older person suggests postural hypotension. Temporary loss of consciousness after urinating, defecating, or coughing suggests situational syncope. Cardiac causes of temporary loss of consciousness such as aortic stenosis or cardiomyopathy are suggested by the occurrence of the event during exercise. Signs of weakness localized to certain areas of the body with temporary loss of consciousness suggest stroke.

The blood pressure and pulse are tested in the lying, sitting, and standing positions. Unequal blood pressures in each arm is a sign of aortic dissection. The heart is examined with a stethoscope to listen for sounds that can indicate valve abnormalities. The nervous system is tested for sensation, reflexes, and motor function to detect conditions of the nerves and brain. An EKG is done to check for abnormal heart rhythms. Other tests may include echocardiograms, rhythm monitoring tests (heart event recorders), and electrophysiologic testing for abnormalities of the heart's electrical system.

When heart conditions are not suspected, tilt-table testing can be used to detect causes of temporary loss of consciousness. Tilt-table testing involves placing the patient on a table with a foot-support. The table is tilted upward and blood pressure and pulse is measured while symptoms are recorded in various positions.

No treatment is needed for many non-cardiac causes of syncope (such as postural hypotension, vasovagal reaction, and situational syncope). The person regains consciousness by simply sitting or lying down. The person is thereafter advised to avoid trigger situations, to not strain while eliminating, to sit when coughing, to lie down for blood drawing, etc.

Older people should have their medications reviewed and caution is advised to slow the process of changing positions from lying to standing. This simple technique can allow the body to adjust to the new position (as the nerves to circulation of the legs adjust slower
Heat and Sun Illnesses Beat the Heat!

There are between 175 and 1250 heat deaths each year in the United States. Most of these deaths result from a general lack of knowledge about how and when heat injuries occur and how they should be treated.

The heat is on
Our bodies produce and maintain heat, even in excessively hot conditions. Our natural method for cooling off is sweat, which is best evaporated by low humidity and wind. But stagnant, humid air makes sweating (cooling) less effective. As our cooling sytem begins to fail, our body (much like a car) begins to overheat, which can lead to heat stroke or heat exhaustion.

What is heat stroke?
Heat stroke is the most serious of heat illnesses and is caused by a body temperature of 105° F or more, where your bodily cooling process fails; mental impairment and death can result. Most cases occur without warning, and a few cases progress from lesser heat injuries, such as heat exhaustion. The classic signs (fever, sluggishness, confusion, and hot and dry skin) may not be present. Heat stroke can damage vital organs, such as the liver, kidneys, and brain.

There are two categories of heat stroke: classic heat stroke and exertional heat stroke. Classic heat stroke mostly affects the elderly, chronically ill, those who do not exercise, and people taking certain medications (such as psychiatric drugs, decongestants, some blood pressure pills, diuretics, and antihistamines). This type of heat stroke is seen during heat waves in unaccustomed areas.

Exertional heat stroke occurs mostly in younger individuals who are strenuously exercising or working in hot conditions. This type of heat stroke results from increased heat production and may cause organ damage.

How do I treat heat stroke?
Treatment of heat stroke involves rapid cooling of body temperature to less than 102.2° F. Evaporative cooling is best: a large fan blows while lukewarm water is sprayed or sponged over the victim. Immersion in an ice-water bath is an alternate. If the victim is far from a health care facility, he or she should be removed from the hot environment and placed in shade or a cool shelter. Unnecessary clothing is removed, and the victim is sprayed with lukewarm water and fanned. If available, ice packs may be placed in the groin and armpits, where large blood vessels act as cooling radiators.

Preventing heat injuries
Most heat injuries can be prevented by knowing the risk factors. They include dehydration, heavy clothing, prolonged exertion (athletics, military exercises, outdoor work), poor conditioning, lack of adaptation, obesity, sleep deprivation, alcohol, poor living conditions, aging, chronic (long-lasting) disease, saunas, and some medications. A major risk factor is a prior heat stroke, which makes you more susceptible to having another one.

Dehydration is avoided by drinking cool water before and during heat exposure (11/2 to 2 cups before, then 1 cup every 20 minutes during heat exposure). Sports drinks that are too sweet, which can interfere with fluid absorption, may be diluted to half strength by adding water. Work and rest cycles can prevent overexertion. During summer sport training programs, the hydration of athletes should be monitored with practice weigh-ins and weigh-outs; athletes who have lost excess water weight (2-3% of body weight) are at higher risk for a heat injury. Despite popular belief, salt tablets should be avoided. Clothing should be loose, breathable, and light in color, and activities should be planned for cooler morning or evening hours whenever possible.

Acclimatization through gradual, daily exposure to heat reduces most forms of heat illness. This natural adaptation takes 10 to 14 days and allows your body to cool off more efficiently. The effects are not permanent, however, and modest continued exposure is needed to maintain them.

Minor heat illnesses, such as heat cramps (cramps in large working muscles), heat edema (swollen feet or ankles), and heat syncope (fainting), do not cause lasting effects and are usually avoided by limiting exposure and becoming acclimatized.

Heat exhaustion
Heat exhaustion, although not as dangerous as heat stroke, is a serious injury. It can progress to heat stroke if not treated immediately. Heat exhaustion itself does not cause damage to vital organs, nor does it cause mental impairment. The body temperature of someone suffering from heat exhaustion is less than 102°F. Symptoms include sweating, headache, dizziness, nausea and vomiting, muscle weakness, cramps, and blurry vision. Dehydration and chronic salt depletion can cause this illness.

How do I treat heat exhaustion?
First, the victim is removed from the hot environment. Then, the victim is cooled off, as with heat stroke. Finally, fluids must be replenished.

Sun illnesses
Our sun emits radiation, and fortunately most harmful radiation is absorbed by the atmosphere. Of the remaining radiation, ultraviolet radiation (UVR) causes the most problems. UVR levels are highest during summer months, especially between 9:00 a.m. and 3:00 p.m. UVR passes through clouds, even causing sunburn on a cloudy day. Environmental factors such as snow, sand, and water reflect UVR and can increase exposure.

There are two main types of UVR: UV A and UV B. UV A causes tanning and had been regarded as safe; however, recent studies suggest that prolonged exposure can lead to cataracts. UV B is more harmful and is responsible for most skin injuries.

How does UVR affect me?
Sunburn is the most common reaction to UVR exposure, resulting in reddened, painful, and blistered skin. The skin cells suffer short-term damage, but repeated exposures can also lead to skin thickening, discoloration, wrinkles, and cancer. Sunburn can occur after just 20 minutes of exposure in peak conditions. Individuals with different skin types have different responses to UVR. Light-skinned persons tend to burn easily, while dark-skinned persons do not.

Snow blindness (photokeratitis) is sunburn of the eye. This painful condition is caused by the heightened exposure from the reflective surface of snow, sand, or water. It usually occurs at higher altitudes, but can affect people who live near a body of water. Snow blindness is temporary, but sun exposure over the years can lead to a cataract (hardening of the eye's lens). Intense light conditions (such as staring at an eclipse) can irreversibly damage the retina (back part) of the eye and cause vision loss.

How can I limit UVR exposure?
Protective clothing (such as long-sleeve shirts and hats) and avoiding peak sunlight hours of 9:00 a.m. to 3:00 p.m. are recommended. Sunscreens help by absorbing UVR before it penetrates into the skin to cause damage. Sun Protection Factor (SPF) is a scale that rates effectiveness; the higher the number, the more protection. Various products resist sweat and water to different degrees. Sunscreen of at least SPF 15 should be worn on exposed areas and reapplied according to the instructions. Sun damage begins in childhood and is cumulative; therefore, children should always be protected. Although sunscreen does offer some protection, you should not spend endless time in the sun.

The best way to protect your eyes is to wear polarized sunglasses. Polarized sunglasses filter out UVR and should be worn for most outdoor activities (including driving). These glasses may reduce the long-term risk of cataracts. "Glacier" glasses with side shields are recommended for high-intensity snow or sea conditions. Non-polarized glasses are dangerous; they trick the eye into an illusion of less light, but do not block harmful radiation.

Heat and sun illnesses are serious. By taking a few preventive measures, however, you can continue to enjoy the outdoors and cut down on the risk of injury.

Matthew McQueen, M.D.
New Orleans, Louisiana