Syncope is a temporary loss of consciousness caused by a reduced bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood flow to the brain.
A Drop in Blood Pressure
When bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure falls below a certain threshold, the brain temporarily stops functioning, leading to a loss of consciousness, often resulting in a fall.
Once the person is lying down, bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood circulation naturally rebalances. The bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood that had pooled in the legs due to gravity returns to the heart, allowing the brain to be properly supplied again. The person then regains consciousness. This type of fainting episode typically lasts less than two minutes.
Warning Signs: Pre-Syncope
Before losing consciousness, certain signs may appear. This is known as pre-syncope or near-fainting. These signs include dizziness, blurred vision, or a brief memory lapse. However, their presence and intensity vary from person to person and depend on the cause of the syncope. Some individuals may not experience any symptoms before fainting.
Other Causes of Loss of Consciousness
It is important to differentiate syncope from other potential causes of fainting, such as:
- Seizures, caused by abnormal and excessive electrical activity in the brain.
- Coma, which refers to prolonged unconsciousness due to brain dysfunction.
- Pulmonary embolism, caused by a bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood clot obstructing an artery in the lungs.
A Common Reason for Medical Consultation
Syncope is a frequent reason for medical visits, accounting for about 1% of emergency department evaluations each year. However, this figure likely underestimates the actual frequency of syncope, as many individuals who experience it do not necessarily seek medical attention.
Different Types of Syncope
Various conditions can lead to a drop in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure and cause syncope. The main categories include:
- Reflex syncope, triggered by an excessive response of the autonomic nervous system, often due to strong emotions, pain, or stress.
- Orthostatic syncope, occurring when moving from a lying or seated position to standing, leading to a sudden drop in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure.
- Cardiac syncope, caused by an underlying heart issue, such as an arrhythmia or an obstruction in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood flow.
Reflex Syncope
Reflex syncope is the most common type of syncope, more frequent than cardiac or orthostatic syncope.
It is named as such because it results from an abnormal brain reflex in response to a stimulus. This reflex alters the autonomic nervous system, affecting circulation and heart rate.
–A Drop in Heart Rate and BloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood Pressure
This reflex causes:
- Bradycardia, meaning a slowing of the heart rate, or even asystole, a temporary pause in heartbeats.
- Dilation of bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood vessels, leading to a drop in bloodBlood is composed of red blood cells, white blood cells, platelets, and plasma. Red blood cells are responsible for transporting oxygen and carbon dioxide. White blood cells make up our immune defense system. Platelets contribute to blood pressure.
When these two phenomena combine, brain perfusion becomes insufficient, causing a loss of consciousness.
Different Types of Reflex Syncope
Reflex syncopes are categorized into several types:
- Vasovagal syncope, often triggered by strong emotions, pain, heat, or prolonged standing.
- Situational syncope, caused by a specific effort (e.g., coughing, urination, swallowing) or a particular stressor.
- Carotid sinus syncope, resulting from hypersensitivity of receptors in the neck arteries, which can be triggered by pressure on the neck (e.g., wearing a tight collar, head rotation).
General Overview of Syncope Causes
The following sections will explore each type of syncope in more detail, including the different forms of reflex syncope.
The distribution of syncope varies with age. In older adults, cardiac and orthostatic causes are more common. The selection of tests and treatments depends on the suspected or identified cause during medical evaluation.
The Importance of Medical History
When a person seeks medical attention for a loss of consciousness, the medical history is a crucial step. The doctor aims to reconstruct the events leading up to the syncope with precision.
Every detail, even if it seems insignificant, can help guide the diagnosis and determine whether additional investigations are necessary.
Conclusion
Syncope is a broad topic due to the variety of possible causes.
In most cases, it is benign and does not increase the risk of cardiovascular disease or mortality. However, it can lead to injuries due to falls. Adjusting lifestyle habits according to the type of syncope often helps reduce its frequency.
Cardiac syncope, on the other hand, requires a more specific approach, as it may indicate an underlying condition that needs treatment.
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