Syncope Flashcards
What is Syncope?
A transient sudden loss of consciousness and postural tone
due to acute decrease in cerebral blood flow
Causes of syncope
Neural causes
Cardiac syncope
Due to metabolic
Hysterical Syncope
Orthostatic Syncope
Subtypes of Neural Syncope
Neural syncope= due to decreased cerebral flow
.Vasomotor syncope
.Postural Syncope
.Cerebral Syncope
.Situational Syncope.
Subtypes of Vasomotor Syncope
Vasovagal Syncope
Carotid Sinus Syndrome
What is Vasovagal Syncope
(Common faint)
Which individuals most susceptible to vasovagal syncope
susceptible
individuals emotional and physical stimuli such as
fright, pain and unpleasant sights, exhaustion, hot
atmosphere, long period of standing in same position
may produce syncope
Symptoms of vasovagal syncope
pale, there
is usually
slow pulse
, low blood pressure and
dilated
pupils
Main cause of carotid sinus syndrome
hypersensitivity of carotid sinus
Susceptible individuals in carotid sinus syndrome
Elderly people in assc. with htn and arteriosclerosis
eg: Tight neck collar +head turning
Symptoms of carotid sinus syndrome
Bradycardia,hypotension,occas. asystole for 10-15 secs
Main cause of postural syncope
failure of baroreceptors which normally adjust heart rate and peripheral
resistance in response to change of posture.
Causes of postural syncope
Arising abruptly from a prolonged period in recumbent position often causes giddiness and syncope particularly in presence of cerebral vascular insufficiency.
(b) Following strenuous physical exercise.
(c) Chronic
orthostatic hypotension may result in giddiness or syncope or both following a decline of systolic pressure
usually at least 30 mm Hg. when the patient remains
stationary in the upright position.
(d) In association
with neurologic disorders
Main cause of cerebral syncope
direct brain damage secondary to trauma or associated with carotid or vertebrobasilar disease
Recureent attacks most in which poture in cerebral syncope
erect posture
Other features in cerebral syncope
In subclavian steal syndrome exercise of the involved arm is
followed by syncope
Causes of situational syncope
Cough ,micturition,basilar artery migraine
Explain syncope due to cough
occur after paroxysms of cough especially in patients with bronchitis and emphysema
increase in
intrathoracic pressure which occurs with coughing
and impedes venous return to the heart.
Explain syncope due to micturition
in men with lower
urinary tract obstruction
excessive straining- to pass urine usually at night
Due to postural fall in
B.P., reflex vagal activity stimulated by a full bladder, and reduced venous return caused by straining
Susceptible people in basilar artery migraine
children with history of severe occipital headache.
Subtypes of cardiac syncope
CVS ,Reflex syncope
causes of cvs syncope
Obstrucn to LV outflow
Obstrucn to Pulm outflow
Cardiac tamponade
Aortic dissection
Arrythmias
What is reflex syncope?
– Cardiac standstill occurring from
reflex vagal activity,
eg:following distension of
viscera, fainting associated with irritation of pleura
or peritoneum, cardiac asystole associated with
oesophagoscopy or bronchoscopy, and in glossopharyngeal neuralgia and cardiospasm, and
pathological lesions in larynx and mediastinum
Subtypes of metabolic causes syncope
Hypoxia,hypoglycemia,hyperventilation
Syncope due to hypoxia in which places and which individuals
– Oxygen lack may occur at high altitudes
or at lower levels of altitude in patients with aortic stenosis, congenital heart disease, pulmonary
hypertension or anemia
C/F of hypoxia induced syncope
Cyanosis at onset
convulsions
Hypoglycemia syncope causes
diabetic patient, or spontaneous due to insulin secreting tumor
Commonly occrs due to (hypogycemia syncope)
Starvation
C/F of hypoglyc
profuse sweating relieved with gluocse
How does hyperventilation cause syncope
respiratory lkalosis
Hysterical Syncope
–Loss of consciousness of psychologic origin. No alteration of pulse or blood pressure.
Syncope managemetn
Management –
(a) Vasovagal attacks and syncope in
general – Immediate treatment is to place the patient at
once in recumbent position in order to restore sufficient
B.P. for cerebral perfusion to be resumed.
(b) Cough syncope – Vigorous treatment of chest condition with antibiotics and antitussive drugs.
(c) Micturition syncope – Patient
on waking at night must be advised to sit on edge of the
bed for a short period before going to lavatory. He should
be encouraged to micturate in the sitting position.
(d)
Carotid sinus syndrome – Anticholinergic drugs or if this
fails surgical denervation of carotid sinus (nerve of Herring).
(e) Postural hypotension – Elevation of foot of bed,
elasticated stockings. Mineralocorticoid fludrocortisone,
indomethacin, sympathomimetic drugs or cardiac pacing
may be indicated
What is Orthostatic syncope
Orthostatic syncope - defined as a reduction in systolic
blood pressure of at least 20 mm Hg or diastolic blood
pressure of at least 10 mm Hg within 3 min of standing
or head-up tilt on a tilt table, a manifestation of sympathetic vasoconstrictor (autonomic) failure
