This presentation is an overview of syncope, its causes and types

1. ‫الرحیم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬

2. Differential Diagnosis of Syncope

3. Syncope (Fainting)
Comprises generalized weakness of muscles, loss of postural
tone, inability to stand upright and a loss of consciousness

4. Faintness (Pre-Syncope)
 Refers to lack of strength with sensation of impending loss of
consciousness.
 "Faintness" reflects the prodromal phase of "fainting" (syncope). The
sequence of symptoms includes increasing light headedness, blurring of
vision proceeding to blackout, heaviness in the lower limbs progressing
to swaying and loss of consciousness.

5. Mechanism
 Fainting (syncope) is a sudden and brief loss of consciousness and postural tone
secondary to hypo perfusion of the brain.
 Cerebral ischemia may be due to sudden vasodilatation, to a sudden fall in cardiac
output or to both simultaneously.

6. Common Precipitating Causes of Syncope
• Warm environment, hot bath
• Post-exercise
• Prolonged motionless standing
• Large meals (carbohydrate load)
• Volume depletion
• Rising after prolonged bed rest
• Rapid postural change
• Valsalva
• Alcohol
• Medications

7. Types
Major types
Vasovagal Syncope Cardiac Syncope
Orthostatic
(Postural Syncope)

8. Vasovagal Syncope
 Mechanisms include reflex slowing of heart mediated through vagus, and marked fall in arterial
pressure and peripheral vascular resistance.
 Causes include emotional stress, warm overcrowded room, sudden pain, mild blood loss, anemia,
fever and fasting.
 Clinical features include a "prodromal phase" characterized by nausea, sweating, yawning,
epigastric distress, tachypnea, weakness and confusion. This is followed by faintness, pallor,
coldness of hand and feet, and eventually loss of consciousness. Physical examination reveals
tachycardia during prodromal phase and bradycardia later with low blood pressure and weak
pulse. Consciousness is regained rapidly without confusion, headache or focal neurologic
symptoms, though fatigue is frequent. Convulsions can result if recumbency is prevented.
 • Vasovagal syncope is common in the young people.

9. Cardiac Syncope
 Cardiac syncope is due to a sudden reduction in cardiac output. This can occur when the heart is
beating too fast or too slow or when it is not beating at all. It can also occur when there is
obstruction to outflow of blood from the heart or cardiac contractility is reduced markedly.
• Complete heart block (Stokes-Adams
Morgagni syndrome)
• Paroxysmal tachycardias (supraventricular
or ventricular)
• Sick sinus syndrome
• Acute massive myocardial infarction
• Aortic stenosis (exertional syncope)
Hypertrophic cardiomyopathy (exertional
syncope)
• Primary pulmonary hypertension
• Pulmonary embolism
• Left atrial ball valve thrombus or myxoma
• Tetralogy of Fallot
• Long QT syndrome
• Brugada syndrome

10. Orthostatic Syncope (Postural Syncope)
 This occurs when the person suddenly gets up from a lying down position or stands still for a long
time. Basic mechanism is postural hypotension resulting from loss of vasoconstrictor reflexes in the
lower limb vessels.
 Common causes of orthostatic hypotension are:
 Physiological
 Idiopathic orthostatic hypotension
 Drugs including antihypertensive drugs

11. Drug-Induced Syncope
Vasodilators/volume depletion
Angiotensin-converting enzyme inhibitors
(ACE inhibitors)
Quinidine
Beta-blockers Amiodarone
Calcium channel blockers Tricyclic antidepressants
Diuretics

12. Syncope Associated with Cerebrovascular
Disease
 Caused by occlusion in the large arteries in the neck.

13. Miscellaneous Causes of Syncope
 Carotid sinus syncope (hypersensitive carotid sinus) is common in elderly patients. It follows some
form of compression on the carotid sinus as in turning the head to one side, tight collar or
shaving over the region of carotid sinus.
 Vagal and glossopharyngeal neuralgia.
 Micturition syncope is seen in elderly patients during or after micturition, particularly after arising
from the bed.
 Cough syncope follows paroxysms of cough in elderly patients with chronic bronchitis. During
coughing, intrathoracic pressure is elevated, resulting in decreased venous return to the heart, in
turn resulting in diminished cardiac output.
 Diaphragm contraction further impedes venous return by vena cava compression.
 Hyperventilation and hysterical fainting.

14. Investigations
 Metabolic parameters, particularly blood sugar, sodium and urea
 Electrocardiogram
 Echocardiography
 Holter monitoring (ambulatory ECG)
 Carotid sinus massage
 Electroencephalogram
 Tilt-table test
 CT head