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Unconsciousness - Syncope

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Causes of unconsciousness

  1. Toxic
    • Endogenous toxicosis (Coma hepaticum)
    • Exogenous toxicosis (particularly alcohol, heroin, sedatives, anti-psychotic drugs)
  2. Cardiovascular
    • Collapse
    • Shock
    • Cardiac arrest
  3. Endocrine
    • Hypoglycaemia
    • Hyperglycaemia
    • Etc.
  4. Cerebral
    • Epilepsy
    • Apoplexy
    • Intracerebral bleeding
    • Etc.
  5. Psychical
    • Hysteria
  6. Anoxaemic
    • Asphyxia
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Definition of syncope

Sudden, spontaneously reversible loss of consciousness caused by reduced cerebral perfusion.

Cardiac syncope is more likely a problem in elderly patients with a history of other diseases.
Younger patients without known disorders rather react with syncope of different aetiology.

Vasovagal syncope

Vasovagal syncope is a neurogenic circulatory disorder triggered via neural pathways in the reflex arch. Therefore, the term "neurocardiogenic syncope" is also used. The lay term for syncope is "fainting" or "passing out".
It is the most common type of syncope in otherwise healthy patients.
Causes are anxiety, pain and stress.
These factors trigger a reflex cascade that induces a drop in sympathetic tone and an increase in parasympathetic activity.

Symptoms
of a beginning vasovagal syncope:

If nausea, cold sweat or a feeling of warmth, vomitus, yawning, muscular weakness, abdominal complaints, hyperventilation, impaired consciousness and vision (tunnel vision, grey vision) and hearing loss occur prior to the syncope, this is indicative of a vasovagal syncope.

  • Vertigo
  • Scotodinia
  • Pale skin
  • Palpitation
  • Sweating
  • Nausea
These symptoms are followed by:
  • Drop in blood pressure
  • Bradycardia
  • Loss of consciousness (sudden short fainting)


A vasovagal mechanism is probable if the syncope occurs in a crowded place, after long standing, under strong psychic strain, with fear, insufficient sleep, with fasting, or if medical devices are used or blood is taken.

Treatment
  • Discontinue the treatment
  • Lay the patient flat
  • Lift the patient's legs
  • Supply fresh air
  • Monitor vital signs (pulse, blood pressure, responsiveness)
  • Treat with etilefrin (e.g. Effortil®), an α and β sympathicomimetic drug
    Contraindications: cardiac arrhythmia and coronary heart disease, among others
  • Administer oxygen via a nasal tube, if needed
In case of persistant unconsciousness:
  • Keep airways open
  • Obtain intravenous access
  • Have somebody call an ambulance
  • Keep the patient warm
  • Monitor the patient

Orthostatic syncope

  • Occurs within seconds to minutes of standing up after reclining/sitting, or after standing for long periods of time

Orthostatic syncope is caused by orthostatic hypotension.
Orthostatic hypotension is indicative of a disturbed blood pressure regulation. Typically, the patient does not experience any symptoms when reclining. Only when the patient changes position or stands/sits erect do symptoms occur. Within seconds to minutes of standing up, the disturbed blood pressure regulation results in a drop of the systolic pressure by at least 20 mmHg. Venous blood pools in the legs. Extended standing can also lead to a drop in systolic pressure.

Treatment
  • Stop treatment
  • Place patient in Trendelenburg position (head approx. 30° lower)
  • Raise the patient's legs
  • Provide fresh air
  • Monitor vital signs (pulse, blood pressure, responsiveness)
  • If necessary, treat with etilefrin (e.g. Effortil®), an α and β sympathicomimetic drug
    Contraindications: cardiac arrhythmia and coronary heart disease, among others
  • Administer oxygen via a nasal tube, if needed

Cardiac syncope

Cardiac syncope is more likely a problem in elderly patients with a history of other diseases.
Low-output syndrome
Cardiac syncope occurs either due to a reduction in cardiac output because of arrhythmia or due to the inability of the heart to adapt the heart's function to higher work loads because of heart disease. An acute decrease in cardiac output with secondary acute reduction of venous backflow can be induced by various causes.

Causes:
Myocardial infarction with insufficient pump function
(see: Myocardial infarction)
Pulmonary embolism
Pulmonary embolism is an occlusion of a lung artery by an embolus (detached thrombus).
The symptoms have an acute onset:
  • Abrupt, intensive dyspnoea/tachypnoea
  • Tachycardia
  • Thoracic pain (increased upon inspiration)
  • Cough
  • Anxiety, feeling of oppression
Cardiac arrhytmias
Cardiac arrhythmias are common.
They can occur in otherwise healthy patients, or are secondary to a disease.

Subjective complaints of the patient:
  • Palpitation
  • Extrasystole
Risks at treatment:
  • Occasional stress-induced dysrhythmias or syncope
  • These can induce haemodynamical disorders leading to cardiac arrest
Risk reduction:
  • Avoid circulatory overload
  • Pay attention to possibly increasing arrhytmia while monitoring the patient
Emergency treatment
  • Elevate the patient's upper body
  • Administer oxygen via a nasal tube
  • While taking measures, have somebody call the emergency service
  • Further treatment depending on the cause

Vena cava compression syndrome

In the last trimester of pregnancy, this type of syncope is induced by supine position of the patient in which the uterus compresses the cave vein.
The cava compression syndrome is characterized by a drop in blood pressure.

Treatment
Put the patient flat onto her left side or in a sitting position.