Types of Syncope: What Are They, Symptoms, and Causes

Write short note on Syncope.

Answer. Syncope is a transient loss or impairment of consciousness with inability to maintain postural tone due to acute decrease in cerebral blood flow.

Syncope Causes

Due to decreased cerebral perfusion

1. Inadequate vasoconstrictive mechanisms

• Vasovagal
• Postural hypotension
• Carotid sinus syncope
• Antihypertensive drugs, i.e., hydralazine, etc.

2. Hypovolemia

• Hemorrhage (blood loss)
• Addison’s disease

3. Reduction of venous return

• Cough
• Micturition
• Mediastinal compression
• Straining at stool evacuation (defecation)

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4. Reduced cardiac output

• Aortic stenosis or hypertrophic subaortic stenosis
• Myocardial infarction
• Cardiac temponade due to pericardial effsion
• Pulmonary embolism

5. Arrhythmias

• AV blocks (2nd degree and 3rd degree or complete
  AV block)
• Ventricular asystole
• Ventricular tachycardia and firillation
• Supraventricular tachycardia

6. Cerebrovascular disturbance

• Transitory ischemic attck
• Hypertension
• Vertebrobasilar insuffiency

Noncirculatory causes

• Hypoxia
• Anaemia
• Prolonged bed rest
• Anxiety neurosis

Types Of Syncope

Vasovagal Syncope

• This is the most common syncope.
• It tends to occur at the time of emotional stress or after an injury or accident or severe pain.
• It involves cardiac slowing because of vagal stimulation and sudden reduction in systemic peripheral resistance due to withdrawal of sympathetic tone.

Postural Hypotension with syncope

• It occurs in patients who have chronic illness or instability of vasomotor reflxes.
• Fall in blood pressure is present in erect posture due to loss of vasoconstrictive reflxes leading to pooling of blood in capacitance vessels of lower limbs.
• It usually occurs on sudden arising from supine position or in the standing position.

Micturition syncope

• It is seen in elder patients during or after urination mainly after arising from sittng position.
• It occurs due to the release of intravesical pressure at the time of micturition which leads to sudden vasodilatation which become augmented by standing causing syncope.

Cardiac syncope

• It occurs due to reduction in sudden cardiac output.
• It occurs due to abnormal decrease or increase in the heart rate.
• Supraventricular tachycardias, cerebrovascular disease,valvular heart disease can cause syncope.

Carotid Sinus Syncope

• It is due to vagal mediated cardiac slowing or due to fall in blood pressure due to depressor response.
• Carotid sinus is sensitive to stretch, so it is induced in sensitive patient by turning head to one side or by tight fitng cervical collar.
• It last for few seconds to few minutes.

Cough Syncope

• It occurs in patients with chronic bronchitis or chronic obstructive pulmonary disease.
  It happens due to the decrease venous return to heart due to rise in intra­thoracic pressure at the time of coughing.

Syncope Of Cerebrovascular Disease

• It occurs due to narrowing of large arteries.
• This is the manifestation of vertebrobasilar insuffiency.
• Excessive physical activity or exercise decreases blood flw to upper part of brainstem leading ot syncope.

Syncope Clinical Features

• Tingling or numbness in the limbs, sudden darkness before eyes and patient has feeling of *blacking out.
• The patient is cold and sweating and fall suddenly to ground and become unconsciousness.
• Patient’s respiration is *sighing.
• Pulse of the patient is slow and limbs are cold and clammy.
• Pupils may retract to light.

Syncope Management

• All the medical/dental procedure or treatment is stopped.
• Remove instruments from oral cavity such as rubber dam,gauze, cottn etc.
• Patient is kept in Trendelenburg position, i.e. patient is kept in a head low and feet up position.
• Loose tighten clothing of patient.
• Aromatic fumes inhalation is given or sprinkle cold water on face of patient for reflx stimulation.
• If recovery is gained escort patient home.
• If recovery is not gained Injection Atropine 0.6 mg IM or I.V. is given.
• If still recovery is not gained look for hypoglycemia and Addison’s crisis
• Start basic life support
• Summon medical help.