What is syncope?
The medical term syncope or collapse or fainting informally describes a brief and self-passing unconsciousness caused by decreased blood flow to the brains. Syncope is a form of 'wegraking', defined as' short-term, self ringing unconsciousness due to a concussion. The loss of consciousness leads to loss of posture due to the loss of muscle tone.
Mechanisms
There are four main groups of causes that result in the blood supply to the brains is temporarily insufficient:
The heart rhythm via either or structural heart disease
- When the arrhythmias usually involves an acceleration or deceleration of the heart rate to increase to a standstill, so that the blood circulation quite abrupt stagnant. Syncope by an arrhythmia can occur under all kinds of circumstances, both at rest and during exercise. Possible additional symptoms are chest pain and palpitations, many are tired and persistent headache, which may result in a collapse.
Inadequate fluid in the body (hypovolemia)
Hypovolemia usually occurs with other disorders, and is also characterized as dehydration. It is rarely an isolated causes of syncope. The risk of syncope by hypovolemia is highest standing. A rare cause, usually the dehydration will also be obvious.
Autonomic failure
If the autonomic nervous system fails, blood vessels in the legs sufficiently squeezed into a standing position, allowing blood drops to the legs. Blood pressure drops from the moment of standing up (orthostatic hypotension) and can within seconds to many minutes, reach a level where the brains no longer function. It occurs in teenagers just after the growth spurt so common that it can be called almost normal. In this case, treatment is hardly ever necessary; advice to sit up straight before getting up is usually sufficient. After a few years the problem is over. Autonomic failure also be caused by medication, then by diseases such as kidney disease and diabetes, and sometimes neurological degenerative diseases.
Reflex
The body has a reflex reducing blood pressure drops and the heart beats more slowly; this reflex works by stimulation of the autonomic nervous system (n. vagus). By stimulating the vagus nerve, there arises a peripheral vasodilatation and bradycardia, which may lead to a syncope. The reflex can be triggered in many ways, the most famous of which concerns the vasovagal syncope, with anxiety, sometimes a slight physical pain stimulus, such as by a blood test or by injection, or the sight of blood, triggering the reflex. Reflex is by far the most common but also the most innocent form of syncope.
All four main types can be divided in various other forms. All forms have some common characteristics, namely those related to decreased blood flow of brains and eyes. These phenomena are seen dark (not always), the unconsciousness itself (always), shocks during the unconsciousness (not always), urinary incontinence (not always), and overturn. In all forms enters the recovery of consciousness at fairly quickly, and the person concerned is good at quickly, which characteristics can help to differentiate with epilepsy, which can also lead to a wegraking.
What is not syncope?
The terminology of syncope, and related disorders has been one of the most confusing throughout the medical world. In the Netherlands, is also used, the word 'collapse', but which is used in practice for all kinds of disorders that are associated with a trap, including even attacks that are not accompanied by loss of consciousness. States where the consciousness is not lost, no wegraking and thus not syncope. This concerns for example the so-called. Hyperventilation syndrome and anxiety disorders. Anxiety itself can indeed provoke syncope, but then there is both fear and syncope; an anxiety attack alone is not syncope. TIA or stroke rarely cause unconsciousness, and there seem to be a physician therefore inappropriate. Other forms of fainting may seem to syncope, but are not. This includes tonic-clonic seizures, and the so-called. "Steal' syndrome.