Neuro chapter 11 Syncope Flashcards
Syncope
Partial or complete LOC with interruption of self-awareness and awareness of surroundings. The LOC is temporary, and recovery occurs spontaneously. Associated with inability to maintain postural tone.
Vasovagal
Due to decreased CO from peripheral vasodilation and bradycardia
Orthostatic hypotension
Due to medications, hypovolemia, autonomic dysfunction
Situational syncope
due to coughing, micturition, or defecation
Cardiac
due to suddent decrease in CO:
aortic stenosis
arrhythmias (heart blocks, V-tach, A-fib/flutter)
SSS
carotid sinus syncope
due to manual pressure/stimulation of the carotid arteries
cerebrovascular disease
due to decreased perfusion of the vertebrobasilar system
other causes
depression, alcohol ingestion, drug abuse, psychogenic, subclavian steal syndrome, cardiomyopathy
neurological
seizures, TIA
Incidence
6% in people older than 75
more common in older adults
unidentifiable cause in 48% of patients
Risk Factors
- underlying cardiac disease
- patients taking antihypertensive agents, antiarrhythmics, antidepressants, diuretics, phenothiazines, vasodilators
- malfunctioning pacemaker
- dehydration
Assessment findings
GENERAL
- feelings of lightheadedness, weakness, nausea, vomiting, diaphoresis
- LOC
- loss of postural tone
- spontaneous recovery
Assessment findings
Vasovagal
Fear, anxiety, or sudden emotion may precipitate syncopal episode
- sudden onset of weakness, sweating, nausea
Assessment
Orthostatic hypotension
- occurs with standing
Assessment
Situational syncope
may be precipitated by swallowing, coughing, micturition, defecation
Assessment
Cardiac arrhythmias
abrupt onset without warning is typical
- related to physical activity
- may be precipitated by electrolyte imbalance (especially potassium, calcium, or magnesium), malfunction of prosthetic heart valve or pacemaker, hypoxia, coronary artery disease
assessment
carotid sinus syncope
- bradycardia often precipitates syncope
- turning of neck may precipitate syncope
assessment
cerebrovascular disease
- may experience auditory, visual, or vestibular symptoms prior to syncope
- may have history of previous transient ischemic attack
Differential diagnosis
vertigo seizure activity cerebellar disease space-occupying lesion in the cranial cavity psychological stress cardiac vs. noncardiac syncope
Diagnostic studies
Goal is to identify….
life-threatening conditions or those associated with significant risk of injury.
Diagnostic studies
- detailed H&P
- ECG
- CMP
- 24-hour ECG monitoring
- BP lying and standing
- flexion/extension of neck 10 times to stimulate vertebrobasilar insufficiency
- complete neuro exam
- carotid auscultation/studies for suspected carotid artery disease: bruit indicates probable blockage.
- ECG if valvular or cardiomyopathy is suspected
- Tilt testing
Prevention
- Rise slowly from lying or sitting to standing.
Nonpharmacologic therapy
- maintain good hydration and normal salt intake
- educate about premonitory signs
- elevate legs if due to vasovagal cause or hypotension
- compression stockings to prevent orthostatic hypotension
- change positions slowly
- teach safety measures (standing on stools, operating heavy machinery)
- increased sodium intake to help expand volume
Pharmacologic therapy
- Targeted toward specific underlying cardiac or neurologic abnormalities
- beta-blockers may prevent recurrent vasovagal symptoms
- antiarrhythmic drugs for documented arrhythmias
- alpha-adrenergic agonists (midodrine) for orthostatic hypotension
Pregnancy/lactation considerations
- vasovagal syncope may present in pregnant women due to compression of the vena cava and aorta
- positioning the pregnany woman on her left side should relieve the compression and the symptoms.
Consultation / referral
- refer to cardiologist or neurologist, depending on etiology
Possible complications
- head injury from falls during episode
- sudden death (more common if cardiac etiology)
